https://www.conservapedia.com/api.php?action=feedcontributions&user=Borbon&feedformat=atomConservapedia - User contributions [en]2020-04-04T02:11:55ZUser contributionsMediaWiki 1.24.2https://www.conservapedia.com/index.php?title=Dinosaur&diff=997865Dinosaur2012-08-02T23:26:02Z<p>Borbon: /* History of dinosaurs */</p>
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<div>{{Taxonomy<br />
|name=Dinosaur<br />
|image=Fdt566e4.jpg<br />
|caption=<br />
|superkingdom=<br />
|kingdom= Animalia<br />
|subkingdom=<br />
|superphylum=<br />
|phylum=Chordata<br />
|subphylum=<br />
|infraphylum=<br />
|microphylum=<br />
|superdivision=<br />
|division=<br />
|subdivision=<br />
|superclass=<br />
|class=Sauropsida<br />
|subclass=Diapsida<br />
|infraclass=Archosauromorpha<br />
|superorder=Dinosauria<br />
|order=Ornithischia; Saurischia <br />
|suborder=<br />
|infraorder=<br />
|superfamily=<br />
|family=<br />
|subfamily=<br />
|supertribe=<br />
|tribe=<br />
|subtribe=<br />
|genera=<br />
|genus=<br />
|subgenus=<br />
|species=<br />
|binomialname=<br />
|sub=<br />
|alt=<br />
}}<br />
'''Dinosaurs''' are extinct animals usually believed to be ranging in size from a few ounces to some of the largest land animals ever to exist. <br />
The word ''dinosaur'' was coined in 1841 by [[Richard Owen]]<ref>Grigg, Russell, [http://creationontheweb.com/content/view/1956/ Dinosaurs and dragons: stamping on the legends], ''Creation''<br />
14(3):10–14, June 1992</ref>, from the Greek words for "terrible lizard", and reflected the creatures' large size and fearsome appearance to the early paleontologists.<br />
<br />
==Highlights of the history of dinosaur paleontology==<br />
[[Image:Osborn.jpg|200px|thumb|right|[[Henry Fairfield Osborn]]]]<br />
In the United States during the 1900s, the public imagination was caught by the discoveries of [[Henry Fairfield Osborn]] (1857-1935) and the great competitive dinosaur hunters, Edward Drinker Cope (1847-1897) and Othniel Charles Marsh (1831-1899). Exploring in Wyoming, Colorado, and New Mexico, they found numerous fossil dinosaurs. Their museums worked out the techniques for mounting and displaying them.<br />
<br />
==Dinosaur Species==<br />
Dinosaurs were immensely varied, and included both herbivores and carnivores. Although many have been found in the fossil record, paleontologists expect that they have barely scratched the surface of the vast superorder that the dinosaurs encompassed.<ref>[http://news.nationalgeographic.com/news/2006/09/060905-dinosaurs_2.html Vast Majority of Dinosaurs Still to Be Found, Scientists Say], ''National Geographic''</ref><br />
<br />
<br />
===History of dinosaurs===<br />
[[Image:Michelangeloflood.jpg|thumb|250px|left|''The [[Great Flood|Flood]]'', by [[Michaelangelo]], detail from the [[Sistine Chapel]], 1509.]]<br />
[[Creation science]] asserts that the biblical account, that dinosaurs were created on day 6 of [[creation]]<ref>''Genesis'' 1:25</ref> approximately [[Counterexamples to an Old Earth|6,000 years ago]], along with other land animals, and therefore co-existed with humans, thus [[Counterexamples to Evolution|debunking the Theory of Evolution]] and the beliefs of evolutionary scientists about the age and creation of the earth. But, of course we all know these people are insane.<br />
<br />
Creation science shows that dinosaurs lived in harmony with other animals, (probably including in the [[Garden of Eden]]) eating only plants<ref>''Genesis'' 1:29-30</ref>; that pairs of each dinosaur [[kind]] were taken onto [[Noah's Ark]] during the [[Great Flood]] and were preserved from drowning<ref>[http://www.creationontheweb.com/content/view/3967/ Were dinosaurs on Noah’s Ark?], ''Creation Ministries International''</ref>; that many of the fossilized dinosaur bones originated during the mass killing of the Flood<ref>Carl Wieland, [http://www.creationontheweb.com/content/view/219/ Dinosaur bones—just how old are they really?], ''Creation'', vol. 21 No. 1 p. 54</ref>; and that possibly some descendants of those dinosaurs taken aboard the Ark are still around today.<ref Name="Today">Robert Doolan, [http://www.creationontheweb.com/content/view/833/ Are dinosaurs alive today?], ''Creation'', vol. 15 No. 4 p. 12.</ref> At least 300 distinct [[genera]] of dinosaur have been identified.<ref>USGS [http://pubs.usgs.gov/gip/dinosaurs/types.html]</ref><br />
<br />
[[Archaeological]], [[fossil]], and documentary evidence supports the [[faith and science|logical]] conclusion that dinosaurs co-existed with mankind until at least relatively recent times.<sup>[citation needed]</sup><br />
<br />
Because the term only came into use in the 19th century, the [[Bible]] does not use the word "dinosaur." However, there are numerous references throughout the biblical account. For example, the [[behemoth]] in [[Job]] and the [[leviathan]] in [[Isaiah]] are clearly references to dinosaurs,<ref>Allan K. Steel, [http://www.creationontheweb.com/content/view/1799 Could Behemoth have been a dinosaur?], ''Journal of Creation'' vol. 15 No. 2 p. 42.</ref> <ref>[http://www.answersincreation.org/job4041a.htm], ''Answers in Creation''</ref> although others have claimed that Behemoth and Leviathan are references to a hippopotamus or elephant and a crocodile respectively. However, the Biblical descriptions do not fit those creatures, note that hippopotamuses and elephants do not have a "tail like a cedar". Furthermore, even if the terms did refer to other animals, this does not necessarily invalidate the existence of dinosaurs. The Creation account was not intended as a comprehensive list of all animals God created - it does not for instance state explicitly that He created the [[ferret]]. However, Genesis does state that God created all animals, which would include any not mentioned by name.<br />
<br />
==== Extinction ====<br />
<br />
Creation science rejects the "Great Impact Theory", pointing out multiple problems with this theory. <ref>Jonathan Sarfati, [http://www.creationontheweb.com/content/view/2426 Did a meteor wipe out the dinosaurs?].</ref><br />
<br />
Creation science shows that evolutionists are frequently coming out with a "New Theory of Dinosaur Extinction" and that their theories are laden with false assumptions. <ref>Michael Matthews, [http://www.answersingenesis.org/docs2002/1115dinosaur.asp Dinosaur demise theory, version #451], ''Answers in Genesis''</ref><br />
<br />
====Dinosaur-like creatures in history and modern sightings====<br />
<br />
Creation science cites a number of reasons to believe that dinosaurs have existed until relatively recent times, and perhaps still survive.<br />
[[Image:AZ_RockArtDino1a.jpg|right|150|thumb|right|Charles W. Gilmore, Curator of Vertebrate Paleontology with the United States National Museum, examined an ancient pictograph which he claimed portrays dinosaurs and man coexisting]]<br />
* There have been a number of sightings of dinosaur-like creatures reported by the [[best of the public]].<br />
** A thousand people reported seeing a dinosaur-like monster in two sightings around Sayram Lake in Xinjiang according to the Chinese publication, China Today.<ref name="Today" /><br />
** Locals in the Congo have reported a creature they name ''Mokele-mbembe''<ref name="Today" /><ref>[http://www.mokelembembe.com/ Mokele-mbembe The Living Dinosaur!]</ref>, and from its description it appears to be a small plant-eating dinosaur. The reports have been taken seriously enough that a biologist from the [[University of Chicago]] has made several expeditions to find the creature. Another biologist has reported seeing the creature.<ref name="Today" /><br />
** Dinosaur-like creatures have been seen by several people in two different parts of [[Papua New Guinea]] since 1990.<ref>Anon., [http://creationontheweb.com/content/view/381 A living dinosaur?], ''Creation'' 23(1):56, December 2000.<br />Irwin, Brian, [http://creationontheweb.com/content/view/5847 Theropod and sauropod dinosaurs sighted in PNG?] 1st July, 2008 (Creation Ministries International).</ref><br />
* There are drawings of creatures resembling dinosaurs.<br />
** An expedition which included Charles W. Gilmore, Curator of Vertebrate Paleontology with the United States National Museum, examined an ancient pictograph which he claimed portrays dinosaurs and man coexisting.<ref>[http://www.creationism.org/swift/DohenyExpedition/Doheny01Main.htm Doheny Scientific Expedition, Hava Supai Canyon, Arizona], ''Creationism.org''</ref><ref>[http://www.christiancourier.com/articles/read/the_hava_supai_dinosaur_carving The Hava Supai Dinosaur Carving], ''ChristianCourier.com''</ref>.<br />
** The Nile Mosaic of Palestrina, a second century BC piece of art, contains a portion which depicts a group of Ethiopians hunting what some claim appears to be a dinosaur; there is much debate on this, however, and most modern art historians consider the mysterious animal to be a lion or a crocodile (the latter theory is supported by the presence of the Greek word for "crocodile" written near the image of the mysterious animal). <ref>[http://www.s8int.com/dinolit2.html Dinosaurs in Literature, Art & History-- Page 2], ''s8int.com''</ref><br />
[[Image:Palestrina1.jpg|right|thumb|A portion of the [[Nile Mosaic of Palestrina]], depicting the hunting of an animal which is often said to resemble a dinosaur (but which appears to be labelled "crocodile" in Greek).]] <br />
* Engravings in the floor of Carlisle Cathedral appear to be of dinosaurs. They are on the tomb of bishop Richard Bell, who died in 1496.<ref>See picture on page 241 of Batten, Don, et. al., 2007, ''The Creation Answers Book''.</ref><br />
* Creatures matching dinosaurs and similar creatures have been described by various people groups.<br />
* Descriptions of [[dragon]]s are widespread and match descriptions of dinosaurs, showing that dragons were real creatures and were actually very likely dinosaurs.<br />
** The World Book Encyclopedia states that: "The [[dragon]]s of legend are strangely like actual creatures that have lived in the past. They are much like the great reptiles [dinosaurs] which inhabited the earth long before man is supposed to have appeared on earth." <ref>Quoted in [http://www.creationscience.com/onlinebook/FAQ25.html What about the Dinosaurs?], ''CreationScience.com''</ref> Dragons exist in the folklore of many European and Asian cultures.<ref name="WB2000">''Dragon'' entry in World Book Millennium 2000 CD ROM</ref> World Book Encyclopedia says, "In Europe, dragons are traditionally portrayed as ferocious beasts that represent the evils fought by human beings. But in Asia, especially in China and Japan, the animals are generally considered friendly creatures that ensure good luck and wealth."<ref Name="WB2000" /><br />
** Dragons appear in the flag of [[Wales]], in traditional [[China|Chinese]] New Years' Day celebrations, and in the Chinese [[calendar]]. Every other creature on the calendar is a real creature.<br />
* That dinosaurs are not known from the fossil record above the [[Cretaceous]] strata is not reason to believe that they have not survived until more recent times.<br />
** Living specimens of orders of animals that were believed to have been extinct for millions of years have been found before, such as the Diatomyidae Squirrel <ref>[[Diatomyidae]] Squirrel [http://news.softpedia.com/news/They-Thought-It-Went-Extinct-11-Million-Years-Ago-19557.shtml]</ref>, the Wollemi Pine <ref>Wollemi Pine ''Biotechnology Australia'' [http://www.biotechnologyonline.gov.au/enviro/wollemi.cfm]</ref> and the [[Coelacanth]] <ref>Sulawesi Coelacanth. ''University Of California, Berkeley''[http://www.ucmp.berkeley.edu/vertebrates/coelacanth/coelacanths.html]</ref> <ref>More on the Coelacanth ''marinebio.org''[http://marinebio.org/species.asp?id=54]</ref>.<br />
* The recent dinosaur tissue find is a strong rebuttal of the claim that dinosaurs lived millions of years ago. <ref>Carl Wieland, [http://www.creationontheweb.com/content/view/3042 Still soft and stretchy], ''Creation Ministries International''</ref><br />
<br />
<!-- The Coelacanth are from a group that had previously been thought to have rudimentary limbs and so be the ancestor of land creatures, but this idea was dropped when living Coelacanths were discovered.<ref>[http://www.users.bigpond.com/rdoolan/coelacanth.html Coelacanth: the world’s oldest fish?]</ref> Biologists see this as merely a minor adjustment to the story of evolution. --><br />
<br />
==== Dinosaurs and birds ====<br />
[[Creation science]] shows that the idea that birds are descendants of dinosaurs is not demonstrated by the evidence <ref>[http://www.creationontheweb.com/content/view/3833/106/ Bird evolution?], ''Creation Ministries International''</ref> <ref>Andy McIntosh, [http://www.creationontheweb.com/content/view/540/ 100 years of airplanes—but these weren’t the first flying machines!], ''Creation'' vol. 26 No. 1 p. 44</ref>, and that the dinosaur-bird connection is even disputed by some evolutionists.<br />
<br />
In his article, "Fifteen ways to refute materialistic bigotry", Dr. [[Jonathan Sarfati]] wrote regarding dinosaurs being descendants of birds:<br />
{{cquote|“The same logic applies to the dinosaur-[[bird]] debate. It is perfectly in order for creationists to cite [[Alan Feduccia|Feduccia]]’s devastating criticism against the idea that birds evolved ‘ground up’ from running dinosaurs (the cursorial theory). But the dino-to-bird advocates counter with equally powerful arguments against Feduccia’s ‘trees-down’ (arboreal) theory. The evidence indicates that the critics are ''both'' right — birds did not evolve either from running dinos or from tree-living mini-crocodiles. In fact, birds did not evolve from non-birds at all!<ref>Jonathan Sarfati, [http://www.creationontheweb.com/content/view/2610 15 ways to refute materialistic bigotry], ''Creation Ministries International''</ref>}}<br />
<br />
Creation science also cites the evolutionist and [[atheism|atheist]] [[Ernst Mayr]]<ref>Matthews, Michael, [http://www.answersingenesis.org/docs2003/1208mayr.asp 99 and still fighting God], 8th December, 2003 (Answers in Genesis).</ref> who stated the following:<br />
{{cquote|“It must be admitted, however, that it is a considerable strain on one’s credulity to assume that finely balanced systems such as certain sense organs (the eye of vertebrates, or the bird’s feather) could be improved by random mutations." <ref>[http://www.creationscience.com/onlinebook/ReferencesandNotes10.html In the Beginning: Compelling Evidence for Creation and the Flood], ''Center for Scientific Creation''</ref> <ref> Find the full quote on [http://books.google.com/books?id=mAIjnLp6r_MC&pg=PA296&lpg=PA296&dq=Ernst+Mayr+1942+%22It+must+be+admitted,+however,+that+it+is+a+considerable+strain+on+one%27s+credulity+to+assume%22&source=bl&ots=TRDzBtumPF&sig=XwvnT327A9sn3Uvs0RLOaQNo5Zo&hl=en&ei=P6H6Te37LMSwhAf03fimAw&sa=X&oi=book_result&ct=result&resnum=1&ved=0CBUQ6AEwAA#v=onepage&q&f=false], starting from line 6. </ref> }}<br />
<br />
The March 2003 issue of ''Scientific American'' is also cited by creation scientists:<br />
{{cquote|Of all the body coverings nature has designed, feathers are the most various and the most mysterious...The origin of feathers is a specific instance of the much more general question of the origin of evolutionary novelties--structures that have no clear antecedents in ancestral animals and no clear related structures (homologues) in contemporary relatives. Although evolutionary theory provides a robust explanation for the appearance of minor variations in the size and shape of creatures and their component parts, it does not yet give as much guidance for understanding the emergence of entirely new structures, including digits, limbs, eyes and feathers...." <ref>Michael Matthews, [http://www.answersingenesis.org/docs2003/0313sciam.asp Scientific American admits creationists hit a sore spot], ''Answers in Genesis''</ref> <ref>[http://www.sciam.com/article.cfm?articleID=000CD7F6-B16F-1E41-89E0809EC588EEDF Which Came First, the Feather or the Bird?], ''Scientific American''</ref>}}<br />
<br />
Creation science also shows that the comparative anatomy analysis done by evolutionists comparing bird bones and dinosaur bones is flawed. <ref>Dr. David N. Menton, [http://www.answersingenesis.org/docs2005/0328discovery.asp "Ostrich-osaurus" Discovery?], ''Answers in Genesis''</ref><br />
<br />
===Evolutionary/Old Earth Perspective===<br />
The view of [[atheism|atheists]], evolutionists, and others who accept the uniformitarian timescale is that dinosaurs existed on earth from 230 million years ago to 65 million years ago. In this view, the entire population of dinosaurs were wiped out by a mass extinction event (usually thought to be a meteorite) about 65 million years ago.<br />
This precludes humans and dinosaurs co-existing. <br />
<br />
====Extinction====<br />
<br />
According to evolutionists, close to 65 million years ago, at the end of the [[Cretaceous]] period, and the beginning of what is called the [[Tertiary]] period, an event occurred which has come to be known as the [[K-T Event]]. This event would have obliterated most life on Earth, plunging the world into something that would now be likened to global nuclear winter, through which few extant species could survive. Although these scientists dispute the nature of the K-T Event (selecting among any number of catastrophes that could have caused the significant global cooling that resulted), most believe that the claimed K-T Event was caused by the collision of a massive asteroid with the Earth, the dust and debris from which would have shrouded the sky for thousands of years, cooling Earth considerably.<ref>Kevin O Pope, "Meteorite impact and the mass extinction of species at the Cretaceous/Tertiary boundary," Proceedings of the National Academy of Science, available at [http://www.pnas.org/cgi/content/full/95/19/11028]</ref> According to this view, the dinosaurs did not survive this cataclysm.<ref>[http://news.nationalgeographic.com/news/2002/08/0823_020823_asteroid.html Prehistoric Asteroid "Killed Everything"], ''National Geographic''</ref> A layer of rock containing high concentrations of [[Iridium]], a metal that is extremely rare on earth but common in asteroids, is said to be due to the vaporization and then fall of dust from the meteorite's impact, and its compression within the subsequent geological record.<ref>''Ibid''</ref>The evidence of a large impact crater can be found in rocks of the [[Yucatán]] Peninsula of the supposed age of this layer.<ref>[http://news.nationalgeographic.com/news/2003/03/0307_030307_impactcrater.html "Dinosaur-Killer" Asteroid Crater Imaged for First Time], ''National Geographic''</ref> <ref>http://www.ucmp.berkeley.edu/education/events/cowen1b.html</ref><br />
Creationists assert that the assumptions underpinning the methods used by modern geologists are incorrect, and even though the validity of a large impact is accepted, this does not constitute proof that the impact caused the extinction of the dinosaurs.{{fact}}<br />
<br />
====An Explosion of new species ====<br />
<br />
Evolutionists speculate that a mass extinction of the dinosaurs removed a major food competitor, and predator, of smaller animals. As a result of a new "vacancy" in the food chain, following the [[K-T Event]], it is theorized that vast speciation occurred, as the evolutionary pressure of a new cold age propelled animal species to adapt or die out. According to this view, [[mammals]] were some of the main beneficiaries of this explosion: their fur allowed them to adapt to the cold, and their small size allowed them to conserve energy relative to the huge dinosaurs of the previous age.<ref>Bennet, Shostak, Jakotsky, "Life in the Universe," viewable at [http://www.amazon.com/Life-Universe-Jeffrey-Bennett/dp/0805385770]</ref><br />
<br />
====Dinosaurs and Birds====<br />
<br />
As a number of feathered fossils (claimed to be dinosaurs) have been discovered, and evolutionary scientists claim the similarity in the bone structure between birds and dinosaurs show that modern birds are a descendants of dinosaurs. This is often cited as an example of [[macroevolution]].<ref>[http://news.nationalgeographic.com/news/2004/10/1006_041006_feathery_dino.html New Dinosaur Discovered: T. Rex Cousin Had Feathers], ''National Geographic''</ref><br />
<br />
==Dinosaur fossils and Human Fossils and Geological Strata ==<br />
Some evolutionary scientists assert that if human bones aren’t found with dinosaur bones, then dinosaurs and man didn’t live together.<ref name="HaD">Hodge, Bodie, [http://www.answersingenesis.org/articles/am/v1/n1/humans-and-dinosaurs If humans and dinosaurs lived together, why don’t we find human fossils with dinosaur fossils?] ''Answers'' 1(1):52, May 2006.</ref><ref>[http://www.talkorigins.org/indexcc/CH/CH710.html Claim CH710] (The TalkOrigins Archive)</ref><br />
Creation scientists point out that this is a false assumption; if human bones aren’t found buried with dinosaur bones, it simply means they weren't buried together.<ref name="HaD" /><br />
<br />
Evolutionists speculate that [[radiometric dating]] of rocks containing dinosaur bones indicates them to have formed between 65 million years ago and 250 million years ago, whereas rocks with human bones in them are dated as being much newer (less than 5 million years old). Creation science shows that those methods of dating rocks provide false results, and therefore reject this argument.<ref>http://creation.com/radiometric-dating-questions-and-answers</ref> <br />
<br />
Creation science points out that the fossil record contains mainly marine organisms and that a small sliver of the fossil record contains vertebrates and thus shows that we shouldn't expect to find many human fossils at all.<ref name="HaD" /><br />
Moreover, as the biblical [[Great Flood|Flood]] would be a marine catastrophe, it would be expected that marine fossils would dominate the fossil record. This is in fact what we find.<ref name="NAB">Hodge, Bodie, [http://www.answersingenesis.org/PublicStore/pdfs/SampleChapter/10-2-267.pdf Why Don’t We Find Human & Dinosaur Fossils Together?] (chapter 13 of the New Answers Book), 2006.</ref><br />
<br />
Approximately 70% of the Earth is covered in salt water which would also explain the dominance of marine fossils. In addition, creation scientists show there may have been a small pre-flood human population and that massive amounts of flood sediment are why we haven’t found human fossils in pre-biblical flood sediments.<ref name="NAB" /><br />
Also, creation scientists point out that we don't find human bones buried with [[coelacanth]]s yet humans and coelacanths coexist today.<ref name="HaD" /><br />
<br />
==Description==<br />
<br />
===''[[Saurischia]]''===<br />
Herbivorous species were almost all quadrupedal. They carried peg-like teeth which cut, rather than chewed, plant material; grinding of food was aided by gastroliths. Carnivorous species were exclusively bipedal. <br />
*Sauropoda<br />
::Species of this infraorder are characterized by long necks and tails, barrel-shaped bodies, and column-like legs. In three families (notably Diplodocidae, Brachiosauridae, and Titanosauroidea) there are species which are of extreme size, in excess of 125 feet in length and 100 tons, making them the largest animals to have walked the earth.<br />
:::''[[Apatosaurus]]'' <br />
:::''[[Brachiosaurus]]'' <br />
:::''[[Ultrasaurus]]'' <br />
:::''[[Seismosaurus]]'' <br />
:::''[[Argentinosaurus]]'' <br />
:::''[[Diplodocus]]'' <br />
<br />
*Theropoda<br />
::Exclusively bipedal; forearms meant for grasping or holding. Fossil evidence for several species indicate pack hunting. <br />
:::''[[Coelophysis]]'' <br />
:::''[[Ornithomimus]]'' <br />
:::''[[Allosaurus]]'' <br />
:::''[[Tyrannosaurus]]'' <br />
:::''[[Deinonychus]]'' <br />
:::''[[Velociraptor]]'' <br />
:::''[[Giganotosaurus]]''<br />
<br />
===''[[Ornithischia]]''===<br />
Species of this group were all herbivorous; most were quadrupedal. Front teeth were lacking, while a predentary bone was present in the front of the lower jaw. Several species (mainly within ''Ceratopsia'') had a distinctive parrot-like beak.<br />
*Ceratopsia<br />
::Species of this infraorder carried one or more horns on their heads, as well as a shield-like frill to protect the neck.<br />
:::''[[Triceratops]]'' <br />
:::''[[Pachyrhinosaurus]]''<br />
:::''[[Torosaurus]]''<br />
:::''[[Protoceratops]]'' <br />
:::''[[Styracosaurus]]'' <br />
*Stegosauria<br />
::Large dinosaurs with a row of bony plates on top of their backs, and several spikes used as a defensive weapon at the end of their tails.<br />
:::''[[Stegosaurus]]''<br />
:::''[[Huayangosaurus]]''<br />
:::''[[Kentrosaurus]]''<br />
*Ankylosauria<br />
::Heavily-armored dinosaurs, some with a row of spikes along each side, and possessing a bony tail club.<br />
:::''[[Ankylosaurus]]'' <br />
:::''[[Euoplocephalus]]'' <br />
:::''[[Edmontonia]]'' <br />
*Ornithopods<br />
::Large, herd-dwelling dinosaurs that could run bipedaly. Several species had a "boss" of bone on their heads (Pachycephalosaurs) which may have been used for head-butting similar to bighorn sheep; others a crest of bone (hadrosaurs) which may have been sound resonators. <br />
:::''[[Camptosaurus]]'' <br />
:::''[[Iguanodon]]''<br />
:::''[[Pachycephalosaurus]]'' <br />
:::''[[Parasaurolophus]]''<br />
:::''[[Edmontosaurus]]''<br />
:::''[[Bactrosaurus]]''<br />
:::''[[Maiasaura]]''<br />
<br />
<br />
== In Popular Culture ==<br />
Dinosaurs have been a fixture of popular culture since their discovery. It is theorized that some of the myths of fantastical creatures stem from the accidental discovery of dinosaur fossils. More recently, dinosaurs have featured in popular stories including books, movies, television, video games, even music.<br />
<br />
Dinosaurs were introduced to a wide modern audience when movies like the Jurassic Park series were released.<br />
== See also ==<br />
<br />
*[[Evolution]]<br />
*[[Theory of Evolution and Cases of Fraud, Hoaxes and Speculation]]<br />
*[[Irreligion and superstition]]<br />
*[[Young earth creationism]]<br />
<br />
==References== <br />
{{reflist|2}}<br />
<br />
[[Category:Dinosaurs]]</div>Borbonhttps://www.conservapedia.com/index.php?title=Science&diff=997863Science2012-08-02T23:23:40Z<p>Borbon: </p>
<hr />
<div>[[Image:Cassini-science-289.jpg|right]]<br />
'''Science''' consists of three aspects: first, it provides systematic descriptions of everything in the world and all of human experience, generally considered as scientific [[knowledge]]. Second, there are the men (and in more recent times, women) of science who have amassed these descriptions and communicate them to everyone else. Third, there are the methods by which they carry out this work (see [[scientific method]]).<br />
Science can be divided into two areas: [[natural science]], dealing with the [[physical]], [[natural]] world,<ref>Soanes and Stevenson called science "the intellectual and practical activity encompassing the systematic study of the structure and behavior of the physical and natural world through observation and experiment."Soanes,C. and Stevenson, A. (eds.) (2005) 'The Oxford Dictionary of English (revised edition)' Oxford University Press, Oxford, U.K.</ref> and [[social science]], dealing with society and human nature.<br />
<br />
People who study science are called [[scientist]]s. Most of the early scientists who started many of the scientific fields, and some of history's greatest thinkers, such as [[Galileo Galilei]] and [[Isaac Newton]], believed in [[God]], or some other higher power, and many were [[creationists]], although the ideas of [[evolutionism]] or [[Darwinism]] were not yet popular.<br />
In addition, [[Christianity]] played a pivotal role in the development of modern science (see [[Christianity and Science]]). With further scientific advancement, the scientific approach has become increasingly [[atheism|atheistic]],<ref>http://www.atheists.org/flash.line/atheism1.htm</ref> rejecting the supernatural. Scientific fields of study observing a clear atheistic bent include [[Counterexamples to Evolution|evolution]], [[global warming]] and much of [[cosmology]] and [[geology]], which are based on a [[Counterexamples to an Old Earth|time frame]] which predates the Christian time of [[creation]].<br />
<br />
Science differs from other methodologies of classifying knowledge in that a scientific theory is a description of the world which in principle is capable of being disproved; this is known as [[falsifiability]]. It is this property which distinguishes science from other possible methods of discovering knowledge, such as just making stuff up.<br />
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[[Epicurus]] is an important figure in the development of the [[scientific method]]. He insisted that nothing should be accepted except that which has been sufficiently tested through direct observation and logical deduction. [[Roger Bacon]] is hailed by many as the father of modern science. His focus on empirical approaches to science was influential. He wrote an encyclopedia, his ''Opus Majus''. <br />
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== Principles of science ==<br />
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The basis of modern science is observation and hypothesis. It involves constructing the best theory to explain an occurrence based on the evidence at the time. <br />
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Economist [[Milton Friedman]] said, "In all of science, progress comes through people proposing hypotheses which are subject to test and rejected and replaced by better hypotheses." [http://www.pbs.org/wgbh/commandingheights/shared/minitext/int_miltonfriedman.html#10]<br />
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The [[scientific method]] consists of two stages, theory formation and theory testing. In the early 20th Century the scientific method was commonly understood to follow the [[inductive reasoning|inductive]] procedure, whereby general statements are derived from a collection of singular observations. It was thought that through this method theories were constructed; a collection of observations led to the formation of a general theory to explain them. Secondly, at the testing stage, it was considered that a hypothesis could be verified through a collection of singular observations.<br />
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[[Karl Popper]], considered by many to be the most important contributor to the philosophy of science in recent times, put forward a damning critique of induction, going so far is to claim that it did not exist. Popper argued that general theories cannot ever be conclusively verified by singular observations, but that such a theory could be conclusively [[Falsifiable|falsified]] by such means.<br />
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The consensus today is based in large part upon the work of Popper, although in general induction is believed to play a part. The modern view is that the scientific method employs both inductive and [[deductive reasoning|deductive]] methods and is characterized by the principle of falsification:<br />
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* A theory is put forward (Popper argues that this is not inductive, but the consensus is that people are led to invent theories based upon previous observations)<br />
* This theory is provisionally assumed to be true for the purposes of testing it.<br />
* Assuming the theory is true, we can logically follow it through to a specific and inevitable outcome, a prediction, which becomes the hypothesis. In order for the hypothesis to be considered scientific it must be falsifiable.<br />
* The hypothesis is repeatedly tested empirically.<br />
* If the observations do not falsify the hypothesis then we accept the theory provisionally (note, we cannot say that it is now 'fact', nor that is has been 'proven')<br />
* If the observations do falsify the hypothesis then we reject it in its current form.<br />
* The theory, or at least parts of it, can then be modified, or a new theory proposed, which takes us back to the beginning of the process.<br />
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Since verification of general theories is logically impossible, science is not, as many believe, a body of accumulated 'facts', but rather a collection of theories that have yet to be falsified. Via falsification we can move closer and closer to the truth, but since verification is not possible, we can never know if we ever reach the goal of 'ultimate truth' itself.<br />
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==Naturalism and science==<br />
Since the beginning of modern science, scientists have worked under the assumption that their subjects of study have been controlled by consistent natural laws.<br />
There is good evidence that this assumption was based on the [[Christianity|Christian]] view that the laws were created by a consistent creator Who didn't change those laws on a whim.<ref>See [[Natural science#Beginnings]]</ref><br />
This assumption is seen as a prerequisite for logical deduction to act on the observations made. Without the assumption that the universe is consistent we cannot apply the lessons drawn from an observation to any area other than the observations themselves. If a [[chemical reaction]] occurs in a given solution in a laboratory in one city it is assumed that the same reaction can occur in a different laboratory in a different city on a different day because the chemical [[solution]] and situations will be the same.<br />
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If a capricious supernatural force was to enter the equation they could not be controlled for and could not be studied.<br />
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The physical sciences largely concern themselves with questions involving the natural, not the supernatural, but this is not the same as assuming that the supernatural does not exist. In addition, there are also the social sciences like [[history]]. [[Christian apologetics|Christian apologists]] maintain that history testifies to the supernatural existing and that the physical sciences (such as [[Biblical archaeology]]) can aid in historical determinations and testify to the existence of God and the truth of biblical Christianity. <br />
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Three broad philosophies have developed in the scientific community.<br />
* "[[Methodological naturalism]]" adheres to [[naturalism]] insofar as it concerns scientific experiments and observations, but does not rule out a personal deity. It does, however, ''[[a priori]]'' rule out the supernatural being an explanation for observations.<br />
* "[[Philosophical naturalism]]" adheres to the belief that there is no beings or forces beyond what can be observed; this [[atheism|atheistic]] view rejects the supernatural, or is skeptical of such beliefs.<br />
* The third approach is to follow the inference to the best explanation regarding whether or not a supernatural or natural cause best explains a past or present observation.<ref>http://creationontheweb.com/content/view/1315/</ref><ref>http://www.cgst.edu/publication/journal/43/J43_203_Forum04Abstract.pdf</ref> For example, this third approach is advocated by [[creation science|creation scientists]] and [[intelligent design]] theorists when it comes to the origins of the natural world. Creation scientists and intelligent design theorists rightfully maintain the falsity of the [[evolution|evolutionary]] position given the lack of evidence for evolutionary position and the many lines of evidence against the evolutionary position. Another example is that the [[First Law of Thermodynamics|first]] and [[Second law of thermodynamics|second]] laws of thermodynamics argue against an eternal [[universe]], and [[creation science|creation scientists]] claim that these laws point to the universe being supernaturally created.<ref>[http://godevidences.net/space/lawsofscience.php Evidences for God From Space&mdash;Laws of Science]</ref><ref>Thompson, Bert, [http://www.apologeticspress.org/articles/2329 So Long, Eternal Universe; Hello Beginning, Hello End!], 2001 (Apologetics Press)</ref><ref>http://www.creationscience.com/onlinebook/AstroPhysicalSciences14.html</ref> But in other respects, such as why [[Krakatoa]] exploded, a natural explanation would be considered the best explanation.<br />
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==Religious cultivation of early modern science==<br />
''See also:'' [[Christianity and Science]], [[Atheism and the suppression of science]]<br />
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According to the historian [[H. Floris Cohen]], there exists two distinct levels of argument along this line of historical scholarship. <ref> [http://books.google.com/books?id=wu8b2NAqnb0C The Scientific Revolution: A Historiographical Inquiry], [[H. Floris Cohen]], University of Chicago Press 1994, 680 pages, ISBN 0-2261-1280-2, pages 308-321 </ref> The first to be proposed was the [[Merton thesis]] in the late 1930's, which parallels the [[The Protestant Ethic and the Spirit of Capitalism|Weber thesis]] in suggesting that the rise of science was due, at first, to a [[protestant work ethic]] but later extended to a more general biblical ethic. The second to be proposed was that of [[Reijer Hooykaas]], who held the rise of early modern science was due to a unique combination of Greek and biblical thought. One of the main aspects of Hooykaas's argument was that the Greek disrespect for manual work prevented an experimental science from truly developing until the biblical view of honoring work with one's hands was socially sanctioned. Hooykaas reaches the conclusion that "Metaphorically speaking, whereas the bodily ingredients of science may have been greek, its vitamins and hormones were biblical." <ref> * [http://books.google.com/books?id=c6TEDHvAbXAC ''Religion and the Rise of Modern Science''], Regent College Publishing, 2000. ISBN 1-5738-3018-6 </ref><br />
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Historian and professor of religion [[Eugene Marion Klaaren|Eugene M Klaaren]] holds that "a belief in divine creation" was central to an emergence of science in seventeenth-century England. The philosopher [[Michael B. Foster]] has published influential analytical philosophy connecting Christian doctrines of creation with empiricism. Historian William B. Ashworth has argued against the historical notion of distinctive mind-sets and the idea of Catholic and Protestant sciences in "Catholicism and early modern science."<ref> [http://books.google.com/books?id=hs2edDIGCqEC ''God and nature''], Lindberg and Numbers Ed., 1986, pp. 136-66; see also [http://cas.umkc.edu/history/faculty/AshworthW/pub.html William B. Ashworth Jr.'s publication list]; this is noted on page 366 of ''Science and Religion'', [[John Hedley Brooke]], 1991, [[Cambridge University Press]]</ref> Historians James R. Jacob and Margaret C. Jacob have published the paper "The Anglican Origins of Modern Science," which endeavors to show a linkage between seventeenth century [[Anglican]] intellectual transformations and influential English scientists (e.g., [[Robert Boyle]] and [[Isaac Newton]]).<ref> [http://www.compilerpress.atfreeweb.com/Anno%20Jacob%20&%20Jacob%20Anglican%20Fdn%20of%20Modern%20Science.htm The Anglican Origins of Modern Science], [[Isis (journal)|Isis]], Volume 71, Issue 2, June 1980, 251-267; this is also noted on page 366 of ''Science and Religion'', [[John Hedley Brooke]], 1991, [[Cambridge University Press]]</ref><br />
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Two well-respected theological surveys, which also illustrate other historical interactions between religion and science occurring in the 18th, 19th, and 20th centuries, are [[John Dillenberger]]'s ''Protestant Thought and Natural Science'' ([[Doubleday]], 1960) and [[Christopher B. Kaiser]]'s ''Creation and the History of Science'' ([[Eerdmans]], 1991).<br />
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{{quotation|When natural philosophers referred to ''laws'' of nature, they were not glibly choosing that metaphor. Laws were the result of legislation by an intelligent deity. Thus the philosopher Rene Descartes (1596-1650) insisted that he was discovering the "laws that God has put into nature." Later Newton would declare that the regulation of the solar system presupposed the "counsel and dominion of an intelligent and powerful Being."<ref> [[John Hedley Brooke]], ''Science and Religion: Some Historical Perspectives'', 1991, [[Cambridge University Press]], ISBN 0-521-23961-3, page 19 </ref><br />
|Historian and [[Oxford University]] [[Science and Religion]] theologian [[John Hedley Brooke]]}}<br />
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[[University of California at Berkeley]]-educated historian [[Ronald L. Numbers]] has stated that this thesis "received a boost" from mathematician and philosopher[[Alfred North Whitehead]]'s ''[[Science and the Modern World]]'' (1925). Numbers has also claimed "Despite the manifest shortcomings of the claim that Christianity gave birth to science&mdash;most glaringly, it ignores or minimizes the contributions of ancient Greeks and medieval Muslims&mdash;it too, refuses to succumb to the death it deserves. The sociologist [[Rodney Stark]] at [[Baylor University]], a [[Southern Baptist]] institution, is only the latest in a long line of Christian apologists to insist that 'Christian theology was essential for the rise of science.'"<ref> ''Science and Christianity in pulpit and pew'', [[Oxford University Press]], 2007, [[Ronald L. Numbers]], p. 4, and p.138 n. 3 where Numbers specifically raises his concerns with regards to the works of [[Michael B. Foster]], [[Reijer Hooykaas]], [[Eugene M. Klaaren]], and [[Stanley L. Jaki]] </ref><br />
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==Notes==<br />
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{{reflist}}<br />
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==See also==<br />
* [[Scientific method]]<br />
* [[Computing]]<br />
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[[category:science]]</div>Borbonhttps://www.conservapedia.com/index.php?title=Theory_of_relativity&diff=997861Theory of relativity2012-08-02T23:17:45Z<p>Borbon: /* Lack of evidence for Relativity */</p>
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<div>''See also [[Counterexamples to Relativity]].''<br />
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The '''theory of relativity''' has been repeatedly contradicted by experiments, such as precise measurements of the advance of the perihelion of Mercury that show a shift greater than predicted by Relativity, well beyond the margin of error. Criticism of the theory, however, caused physicist [[Robert Dicke]] to be denied the [[Nobel Prize]], and it is unlikely tenure or a Ph.D would be awarded to any critic of the theory.<br />
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'''Relativity''' refers to two closely-related mathematical theories in [[physics]]:<br />
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*'''[[Special theory of relativity|Special relativity]]''' (SR) is a theory which describes the laws of motion for non-accelerating bodies traveling at a significant fraction of the [[speed of light]]. As speeds approach zero, Special Relativity tends towards equivalence with [[Newton's Laws of Motion]]. Special Relativity was developed by [[Hendrik Lorentz]], [[Henri Poincaré]], and Hermann Minkowski,<ref>"German mathematician who developed the geometrical theory of numbers and who made numerous contributions to number theory, mathematical physics, and the theory of relativity." [http://www.britannica.com/eb/article-9052860/Hermann-Minkowski Hermann Minkowski -- Britannica Online Encyclopedia]</ref><ref>[http://www-groups.dcs.st-and.ac.uk/~history/Biographies/Minkowski.html Hermann Minkowski, Biography]</ref> and [[Albert Einstein]]. <br />
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*'''[[General theory of relativity|General Relativity]]''' (GR) is a theory which explains the laws of motion as viewed from accelerating reference frames and includes a geometric explanation for gravity. This theory was developed by [[David Hilbert]] and [[Albert Einstein]] as an extension of the postulates of Special Relativity.<ref>"[T]he German mathematician David Hilbert submitted an article containing the correct field equations for general relativity five days before Einstein."[http://nobelprize.org/educational_games/physics/relativity/history-1.html Nobel Prize historical account]</ref> A dramatic but later discredited claim by Sir [[Arthur Eddington]] of experimental proof of General Relativity in 1919 made Einstein a household name.<br />
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These theories have augmented earlier approaches, such as [[Galilean Relativity]].<br />
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Unlike most of physics, the theories of relativity have discontinuities whereby the limit of a physical quantity as a variable (such as mass or velocity) approaches a fixed value is not the same as the physical quantity at the fixed value. For example, the limit of momentum as mass approaches 0 and velocity approaches the speed of light is not equal to the momentum of (massless) light.<ref>Discontinuities in General Relativity are also well-recognized. See, e.g., [http://www.springerlink.com/content/u47l341u2q555455/]</ref><br />
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More generally, and also unlike most of physics, the theories of relativity consist of complex mathematical equations relying on several hypotheses. For example, at Hofstra University general relativity is taught as part of an upperclass math course on differential geometry, based on three stated assumptions.<ref>http://people.hofstra.edu/Stefan_Waner/diff_geom/tc.html</ref> The equations for special relativity assume that it is forever impossible to attain a velocity faster than the speed of light and that all inertial frames of reference are equivalent, hypotheses that can never be fully tested. Relativity rejects Newton's [[action at a distance]], which is basic to Newtonian gravity and [[quantum mechanics]]. The mathematics of relativity assume no exceptions, yet in the time period immediately following the origin of the universe the relativity equations could not possibly have been valid.<br />
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Relativity has been met with much resistance in the scientific world. To date, a Nobel Prize has never been awarded for Relativity.<ref>Increasingly the Nobel Prize Committee has attempted to relate its physics awards to Relativity in some way, including perhaps 20 of the more recent prizes.</ref> Louis Essen, the man credited with determining the speed of light, wrote many fiery papers against it such as ''The Special Theory of Relativity: A Critical Analysis''.<ref>http://ephysics.fileave.com/physics/Essen/oxford5-essen.pdf</ref> Relativity is in conflict with [[quantum mechanics]],<ref>For example, Relativity claims that space and time are smooth and continuous, while [[quantum mechanics]] suggests otherwise. [http://www.csmonitor.com/Science/Cool-Astronomy/2010/1025/Is-the-universe-a-big-hologram-This-device-could-find-out.] Relativity also denies [[action-at-a-distance]], while quantum mechanics suggests otherwise. Relativity denies any role for chance, while quantum mechanics is heavily dependent on it.</ref> and although theories like [[string theory]] and [[quantum field theory]] have attempted to unify relativity and quantum mechanics, neither has been entirely successful or proven.<br />
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Unlike [[Classical mechanics|Newtonian physics]], in which space and time intervals are each invariant as seen by all observers, in SR the only invariant quantity is a quadratic combination of space and time intervals (x<sup>2</sup> - c<sup>2</sup> t<sup>2</sup>). The (assumed) instantaneous transmission of Newtonian gravitational effects also contradicts special relativity.<br />
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In quantum mechanics, the [[uncertainty principle]] suggests that virtual particles can sometimes travel faster than the speed of light which would violate causality, but "[t]he only known way to resolve this tension involves introducing the idea of antiparticles."<ref>http://nobelprize.org/nobel_prizes/physics/laureates/2004/wilczek-lecture.pdf (p. 102)</ref> Consequently, in 1928 Paul Dirac derived the Dirac equation, one of the first quantum mechanical equations compatible with special relativity, by which Dirac predicted the existence of antimatter. Four years later, antimatter (the positron) was discovered by Carl Anderson, as successfully predicted by relativistic quantum mechanics. [[Quantum field theory]], a generalization of quantum mechanics, is fully compatible with special relativity but not with general relativity, and still lacks a vital piece: evidence of the [[graviton]].<br />
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== Special Relativity ==<br />
Lorentz and Poincare developed Special Relativity as way of understanding how Maxwell's equations for electromagnetism could be valid in different frames of reference. Einstein famously published an explanation of Poincare's theory in terms of two assumptions (postulates):<br />
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# ''The [[speed of light]] is constant for all (inertial) observers, regardless of their velocities relative to each other.''<br />
# ''The laws of physics are identical in all inertial reference frames.''<br />
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In layman's terms, these two assumptions can be restated as:<br />
# It is impossible ever to transmit information faster than the speed of light.<ref>This assumption is commonly restated in this manner. For example, a discussion of hypothetical [[tachyons]] talks "about using tachyons to transmit information faster than the speed of light, '''in violation of Special Relativity'''."[http://www.math.ucr.edu/home/baez/physics/ParticleAndNuclear/tachyons.html] However, there is some question whether the Theory of Special Relativity really restricts faster-than-light communication of information.</ref><br />
# The laws of physics are identical, without any variation, in every location throughout the universe.<br />
# The laws of physics are identical, without any variation, no matter how fast something is traveling (in the absence of acceleration).<br />
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Or, in more concise, clearer terms, these assumptions are this:<br />
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#there is no [[action at a distance]] (because that would make observations dependent on the frame of reference)<br />
#space and time are completely symmetric throughout the universe (because otherwise frames of reference would not be interchangeable)<br />
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When the assumptions are stated clearly as above, the weaknesses in the theory are more apparent. There “is” action at a distance in [[quantum entanglement]] and apparently also in gravity, as no gravitons can be found. However, no information has yet been transmitted via quantum entanglement, so while non-locality violates the spirit of relativity it is consistent with it if relativity is limited to the transmission of information. [[Quantum field theory]], an attempt to partially reconcile [[quantum mechanics]] with relativity, is incomplete at best. As to the second assumption, it is contrary to the [[arrow of time]], which illustrates the lack of symmetry in time. Logical defects include the incoherence of relativistic mass (see discussion below) and the lack of relativistic constraints near the beginning the universe (see above).<br />
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Special Relativity (SR) was initially developed by [[Henri Poincaré]] and [[Hendrik Lorentz]], working on problems in electrodynamics and the [[Michelson-Morley experiment]], which had not found any sign of [[aether (science)|luminiferous aether]], which was believed to be the substance which carried electromagnetic waves. Special relativity alters [[Isaac Newton]]'s laws of motion by assuming that the speed of light will be the same for all observers, despite their relative velocities and the source of the light. (Therefore, if A sends a beam of light to B, and both measure the speed, it will be the same for both, no matter what the relative velocity of A and B. In Newtonian/Galilean mechanics, If A sends a physical object at a particular velocity towards B, and nothing slows it, the velocity of the object relative to B depends on the velocities of the object and of B relative to A.)<br />
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At low speeds (relative to light-speed), the Lorentz-Poincare relativity equations are equivalent to Newton's equations. The media-promoted equation ''[[E=mc²]]'', implausibly suggests a relationship between typically unrelated concepts of energy, the rest mass of a body and the speed of light.<br />
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Under relativity, particles at low mass and low speed can be accurately approximated by [[classical mechanics]] (such as [[Isaac Newton]]'s laws of motion). At the two extremes, modeling the behavior of electrons requires that relativistic effects be taken into account (the chemically significant phenomenon of electron spin arises from relativity), and the course light passing through a region containing many massive bodies such as galaxies will be distorted ([[classical mechanics]], in which light travels in straight lines, does not predict this). These are both experimentally confirmed (electron spin was known before relativity arose, and telescopic observations confirm that galactic clusters distort the paths of the light passing through them).<br />
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Many scientists have indicated problems with the postulates of special relativity. Paul Davies, formerly of Macquarie University and now at the University of Arizona believes that the speed of light has changed over time. Since the speed of light is a constant speed 'c' this indicates problems with the theory [http://news.bbc.co.uk/2/hi/science/nature/2181455.stm light speed]. Other engineers and scientist have written about problems in the basic set of special relativity equations. Based on the ideas of not Einstein but of the scientist Fitzgerald as well as others, a length contraction effect was predicted as an explanation of the failure of the Michelson Morley experiment. This idea was taken up by Hendrik Lorentz and shown by others to be a useful mechanism by which theory could be forced into conformance with experimental results. However, in 2005, Michael Strauss a computer engineer invalidated much of Special Relativity theory by showing clear contradictions in the theory. [http://www.relativitycollapse.com relativity]<br />
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== General Relativity ==<br />
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General Relativity is a theory of gravity that is compatible with Special Relativity. Einstein explains a thought experiment involving two elevators. The first elevator is stationary on the Earth, while the other is being pulled through space at a constant acceleration of g. Einstein realized that any physical experiment carried out in the elevators would give the same result. This realization is known as the equivalence principle and it states that accelerating frames of reference and gravitational fields are indistinguishable. General Relativity is the theory of gravity that incorporates Special Relativity and the equivalence principle. <br />
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General Relativity is a mathematical extension of Special Relativity. GR views space-time as a 4-dimensional [[manifold]], which looks locally like [[Minkowski space]], and which acquires [[curvature]] due to the presence of massive bodies. Thus, near massive bodies, the geometry of space-time differs to a large degree from [[Euclidean geometry]]: for example, the sum of the angles in a triangle is not exactly 180 degrees. Just as in classical physics, objects travel along [[geodesic]]s in the absence of external forces. Importantly though, near a massive body, geodesics are no longer straight lines. It is this phenomenon of objects traveling along geodesics in a curved spacetime that accounts for gravity.<br />
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At one time the anomalous precession of Mercury's [[perihelion]] seemed to support the Theory of General Relativity, but increasingly accurate measurements show a divergence of the data from the theory.<ref>[[Counterexamples to Relativity]].</ref> There are other explanations based in Newtonian gravity, such as factoring in the pull of the other planets on Mercury's orbit. One Newtonian explanation requires a slight alternation to the precise inverse-square relation of Newtonian gravity to distance, which is disfavored by mathematicians due to its inelegance in integrating.<br />
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British Historian Paul Johnson declares the turning point in 20th century to have been when fellow Briton Sir [[Arthur Eddington]], an esteemed English astronomer, ventured out on a boat off Africa in 1919 with a local Army unit to observe the bending of starlight around the sun during a total eclipse. Upon his return to England declared that his observations proven the theory of relativity. In fact recent analysis of Eddington's work revealed that he was biased in selecting his data, and that overall his data were inconclusive about the theory of relativity. The prediction was later confirmed by more rigorous experiments, such as those performed by the [[Hubble Space Telescope]] <ref>[http://www.spaceimages.com/gravlen.html Hubble Gravitational Lens Photo]</ref><ref> [http://csep10.phys.utk.edu/astr162/lect/galaxies/lensing.html Gravitational Lensing] </ref><ref>[http://www.iam.ubc.ca/~newbury/lenses/glgallery.html]</ref>. Lorentz has this to say on the discrepancies between the empirical eclipse data and Einstein's predictions.<br />
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::''It indeed seems that the discrepancies may be ascribed to faults in observations, which supposition is supported by the fact that the observations at Prince's Island, which, it is true, did not turn out quite as well as those mentioned above, gave the result, of 1.64, somewhat lower than Einstein's figure.''<ref>Lorentz, H.A. [http://ia331314.us.archive.org/2/items/theeinsteintheor11335gut/11335-h/11335-h.htm The Einstein Theory of Relativity]</ref><br />
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The prediction that light is bent by gravity is predicted both by Newtonian physics and relativity, but relativity predicts a larger deflection.<br />
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Special relativity is the limiting case of general relativity where all gravitational fields are weak. Alternatively, special relativity is the limiting case of general relativity when all reference frames are inertial (non-accelerating and without gravity).<br />
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==Lack of evidence for Relativity==<br />
The Theory of relativity assumes that time is symmetric just as space is, but the biggest early promoter of relativity, Arthur Eddington, coined the term "[[arrow of time]]" admitting how time is ''not'' symmetric but is directional. The passage of time is tied to an increase in disorder, or [[entropy]]. The Theory of relativity cannot explain this, and implicitly denies it, specifically allowing for theoretical time travel (e.g., [[wormholes]]) and different rates of passage of time based on velocity and acceleration.<br />
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Claims that relativity was used to develop the [[Global Positioning System]] ([[GPS]]) are false. A 1996 article explains:<br />
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:"The Operational Control System (OCS) of the Global Positioning System (GPS) does not include the rigorous transformations between coordinate systems that Einstein's general theory of relativity would seem to require - transformations to and from the individual space vehicles (SVs), the Monitor Stations (MSs), and the users on the surface of the rotating earth, and the geocentric Earth Centered Inertial System (ECI) in which the SV orbits are calculated. There is a very good reason for the omission: the effects of relativity, where they are different from the effects predicted by classical mechanics and electromagnetic theory, are too small to matter - less than one centimeter, for users on or near the earth."<ref>http://tycho.usno.navy.mil/ptti/1996/Vol%2028_16.pdf</ref><ref>Some do claim that relativity is "vital" to GPS even though GPS developed independently of theoretical predictions and theoreticians disagree about how the relativistic effects for GPS should be calculated. ''See id. See also'' [http://www.rand.org/pubs/monograph_reports/MR614/MR614.appb.pdf]</ref><br />
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This article, which was published in 1996, goes on to propose relativistic corrections that might be used to design more accurate GPS systems. Clocks on board GPS satellites require adjustments to their clock frequencies if they are to be synchronized with those on the surface of the Earth. <br />
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Tom Van Flanders, an astronomer hired to work on GPS in the late 1990s, concluded that "[t]he GPS programmers don't need relativity." He was quoted as saying that the GPS programmers "have basically blown off Einstein."<ref>http://archive.salon.com/people/feature/2000/07/06/einstein/index.html See also [http://www.metaresearch.org/solar%20system/gps/absolute-gps-1meter-3.ASP], where Van Flandern discusses how relativistic corrections might improve GPS accuracy.</ref> Asynchronization can be easily addressed through communications between the satellites and ground stations, so it is unclear why any theory would be needed for GPS. While Van Flandern believed that relativity is unnecessary for GPS, he also asserted that observations of GPS satellites supported both general and special relativity, writing that "we can assert with confidence that the predictions of relativity are confirmed to high accuracy over time periods of many days," with unrelated factors interfering with longer-term observations. <ref>http://www.metaresearch.org/cosmology/gps-relativity.asp</ref><br />
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Some internet articles claim that GPS timing differences ''confirm'' the Theory of Relativity or its Lorentzian counterpart (which uses a preferred frame of reference). GPS clocks run slower in the weaker gravitation field of the satellites than on ground stations on Earth, with the effects predicted by general relativity far outweighing the effects predicted by special relativity. However, the articles claiming that the slower GPS satellite clocks confirm relativity do not address the effect, if any, of the weaker gravitational force under Newton's theory on the GPS satellite clocks, likely because in Newtonian Mechanics every clock in the universe keeps time at the same rate regardless of velocity, acceleration, or the presence or absence of force.<br />
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Currently, GPS satellites are synchronized to Coordinated Universal Time by radio signals from the ground; therefore, they cannot currently be used to test general relativity.<ref>[http://www.phys.lsu.edu/mog/mog9/node9.html "General Relativity in the Global Positioning System."] Neil Ashby, U. of Colorado</ref><br />
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There are claims that the effects of relativity have been observed with the frequency shift of the signal being sent back to [[Earth]] several times as various spacecraft have dipped into the gravity wells around massive objects such as the [[sun]] (see image at right)<ref>[http://saturn.jpl.nasa.gov/news/press-releases-03/20031002-pr-a.cfm Saturn-Bound Spacecraft Tests Einstein's Theory]</ref> or Saturn<ref>[http://www.newscientist.com/article/mg12517102.600-science-encounter-with-saturn-confirms-relativity-theory.html Encounter with Saturn confirms relativity theory]</ref>. A satellite called [[Gravity Probe B]] was put in orbit about the Earth to examine the effects of frame dragging and geodetic warping of space<ref>[http://www.nasa.gov/mission_pages/gpb/index.html NASA Gravity Probe B mission page]</ref><ref>[http://einstein.stanford.edu/ Gravity Probe B project page]</ref>, but the results were inconclusive. Note, however, that Newtonian mechanics also predicts deflection of light by gravity, and in the initial theory of relativity it predicted the same amount of deflection, but only if we treat light as capable of being accelerated and decelerated like ordinary matter, which is contrary to all measurements and observations to date.<ref>http://www.mathpages.com/rr/s6-03/6-03.htm</ref> Adjustments to the theory of relativity resulted in a prediction of a greater deflection of light than that predicated by Newtonian mechanics, though it is debatable how much deflection Newtonian mechanics should predict. <br />
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None of the NASA spacecraft incorporates predictions of relativity into their own timing mechanisms, as Newtonian mechanics is adequate even for probes sent deep into space so long as they do not undergo accelerations near the speed of light or enter any massive gravity wells.<ref>There is no reported reliance on relativity by any space probe.</ref><br />
<br />
A decade of observation of the [[pulsar]] pair [[PSR 1913 16|PSR B1913+16]] detected a decline in its orbital period, which was attributed to a loss in energy by the system. It is impossible to measure the masses of the pulsars, their accelerations relative to the observers, or other fundamental parameters. Professors Joseph Taylor and Russell Hulse, who discovered the binary pulsar, found that physical values could be assigned to the pulsars to make the observed decline in orbital period consistent with the Theory of General Relativity, and for this they were awarded the 1993 [[Nobel Prize]] for Physics, which is the only award ever given by the Nobel committee for the Theory of Relativity.<ref>http://nobelprize.org/nobel_prizes/physics/laureates/1993/press.html</ref> In 2004, Professor Taylor utilized a correction to the derivative of the orbital period to fit subsequent data better to the theory. At most, assumptions can be made and altered to fit the data to the theory, rather than the data confirming the theory.<br />
<br />
The [[perihelion]] of Mercury's [[orbit]] [[precession|precesses]] at a measurable rate, but even after accounting for gravitational perturbations caused all other planets in the [[solar system]], Newton's theory (assuming a precise inverse-square relationship for distance) predicts a rate of precession that differs from the measured rate by approximately 43 [[arcsecond]]s per century. General relativity was developed in part to provide an estimate for this rate of precession that better matches observations.<ref>http://physics.ucr.edu/~wudka/Physics7/Notes_www/node98.html#SECTION032121000000000000000</ref> <ref> http://www.alberteinstein.info/gallery/pdf/CP6Doc30_English_pp146-200.pdf</ref> <ref> http://farside.ph.utexas.edu/teaching/336k/lectures/node117.html</ref> Newton's theory can also explain this perihelion by making tiny adjustments to parameters in the gravitational equation.<br />
<br />
General relativity predicts twice as much bending in light as it passes near massive objects than Newton's theory might predict.<ref>http://www.mathpages.com/rr/s6-03/6-03.htm</ref> This phenomenon is known as [[gravitational lens|gravitational lensing]]. A large number of instances of gravitational lensing have been observed, and it is now a standard astronomical tool.<ref> http://imagine.gsfc.nasa.gov/docs/features/news/grav_lens.html</ref> <ref> http://astro.berkeley.edu/~jcohn/lens.html</ref> <ref> http://www.iam.ubc.ca/~newbury/lenses/glgallery.html</ref> Note, however, that the extent of bending of light predicted by Newton's theory is open to debate, and depends on assumptions about the nature of light for gravitational purposes.<ref>http://cosmictimes.gsfc.nasa.gov/1919/guide/gravity_bends_starlight.html</ref><br />
<br />
In 1972, scientists flew extremely accurate clocks ("atomic clocks") around the world in both directions on commercial airlines, and claimed to observe relativistic time dilation; the eastbound clock gained 273 ns and the westbound clock lost 59 ns, matching the predictions of general relativity to within experimental accuracy.<ref>[http://www.answers.com/topic/hafele-keating-experiment Hafele-Keating Experiment]</ref> However, the inventor of the atomic clock, Louis Essen, declared that the experiment was inaccurate.<ref>Louis Essen, Electron. Wireless World 94 (1988) 238.</ref> Dr A. G. Kelly examined the raw data from the experiment and declared it inconclusive.<ref>A. G. Kelly,Reliability of Relativistic Effect Tests on Airborne Clocks, Monograph No.3 Feb.1996, The Institution of Engineers of Ireland, ISBN 1-898012-22-9</ref> The Nobel Committee chose not to honor this experiment for the significance that was claimed.<br />
<br />
Despite [[censorship]] of dissent about relativity, evidence contrary to the theory is discussed outside of [[liberal]] universities.<ref>http://scitizen.com/screens/blogPage/viewBlog/sw_viewBlog.php?idTheme=8&idContribution=922</ref><br />
<br />
==Experiments that Fail to Prove Relativity==<br />
<br />
The different effects predicted by special relativity, compared to classical formulations, are extremely tiny. Most relativistic effects are negligible at the speeds of ordinary phenomena observed by humans. The effects only become significant when the speeds involved are a significant fraction of the speed of light, which is <math>3 \times 10^8</math> meters per second&mdash;such speeds are called ''relativistic''. (However, it's worth noting that ordinary magnetism can be considered an effect of relativity, dictated by the need for electrostatic theory to be correct under relativity. The speed of light in fact appears in the formulas ([[Maxwell's Equations]]) governing electricity and magnetism, though these equations were developed long before relativity was proposed.)<br />
<br />
Because the effects of relativity are so tiny, scientists have been devising sophisticated and sensitive tests ever since the theory was formulated in 1905.<br />
<br />
*At the end of Einstein's original 1905 paper [http://www.fourmilab.ch/etexts/einstein/E_mc2/www/ "Does the Inertia of a Body Depend its Energy Content?"], he speculates on the possibility that the equation <math>E = m c^2</math>, which would normally be very hard to verify, could be verified with the extremely high energies of the newly-discovered phenomenon of radioactivity.<ref>This equation is not related to [[quantum mechanics]].</ref> In the 1910's, with the invention of the mass spectrometer, it became possible to measure masses of nuclei accurately. This led to the clearing up of the mystery of atomic masses not being exact integers,and strongly suggested the existence of a "mass defect" (or "packing fraction") consistent with the mass-energy equivalence. In the 1930's, experiments with known nuclear reactions showed a very accurate correlation between the masses of the nuclei involved and the energy released.<br />
<br />
*Another prediction of special relativity was time dilation in rapidly moving objects. This effect was most famously verified in the anomalously slow decay of relativistic cosmic muons<ref>Some have suggested that other explanations are possible for this effect. We are trying to track this down.</ref>. Time dilation has since been verified many times, and is routinely taken into account in all high-energy nuclear physics experiments, as in Hadron collision experiments<ref>Experiments specifically designed to check dilation are rarely conducted any more.</ref>.<br />
<br />
Predictions of general relativity turned out to be more obscure and difficult to test. The two most famous predictions were the bending of light in a gravitational field and the precession of the perihelia of orbiting planets.<br />
<br />
*The first of these was famously tested during a total eclipse in 1919. That test was somewhat muddled by an incorrect initial calculation, by several people including Einstein himself, of what the effect would be, and some "cherry picking" of the data to be used <ref>''Einstein's Luck'', John Waller, Oxford University Press, ISBN 0-19-860719-9</ref>. The data selection could be considered "manipulation" or "fudging", by a person (Arthur Eddington) who had a personal stake in the outcome. His analysis techniques would not pass muster today.<br />
<br />
:It should be noted that pre-relativistic (Newtonian) physics may also predict a bending, of half the observed value, depending on whether one uses the 17<sup>th</sup> century "corpuscular" formulation or the 19<sup>th</sup> century "wave" formulation.<br />
<br />
:Nevertheless, it has been verified with ever-increasing precision in subsequent eclipses, and in the observations of quasar 3C273.<br />
<br />
*The second "classical" test of general relativity was the advance of the perihelion of the orbit of Mercury. There are many complex effects contributing to this, including gravitational perturbations from other planets and the effect of the oblateness of the Sun. These are hard to calculate accurately, but, by 1900 it was known quite accurately that there was an "anomalous" precession, that is, a precession beyond all other known effects, of 43 arc seconds per century. This is a very tiny effect, but astronomical measurements were sufficiently accurate by that time to show it clearly.<br />
<br />
:This created quite a problem&mdash;physicists by then were accustomed to having their theories check out very accurately. One proposal that was made, by Simon Newcomb and Asaph Hall, was that the exponent of the radius in the gravitational formula wasn't exactly 2. He showed that, by choosing an exponent of <math>2+\delta</math>, the precession, as a fraction of a full orbit per planet's year, is <math>\delta/2</math>. By setting <math>\delta</math> to .000000157, that is, an exponent of 2.000000157, Newcomb was able to get a precession of .000000078 revolutions per Mercury year, or 43 arcseconds per Earth year. The primary resistance to this approach came from mathematicians unable to do the integration without an exponent of precisely 2, and they insisted, incorrectly, that was impossible for the exponent to be slightly different from 2. Due to this desire for mathematical elegance rather than objective observation-based science, Newcomb's approach was not pursued. Furthermore as can be seen from the table below the measured values of the anomalous precessions of other planets agree well with the predictions of general relativity but poorly with those predicted by Newcomb and Hall.<br />
<br />
:While Newcomb's theory, and general relativity, don't lead to closed-form solutions, both theories can be solved numerically to as much precision as one desires.<br />
<br />
:Increasingly precise measurements of the precession demonstrate that it conflicts with General Relativity, despite claims of relativists for decades that it predicted the precession accurately in the amount of <math>3{}v^2/c^2</math> revolutions per planet's "year", where <math>v</math> is the planet's average orbital speed.<ref>That is a simple approximation, designed to relate the precession to the planet's speed relative to the speed of light. A more accurate approximation is <math>\frac{3GM}{c^2 a(1-e^2)}</math>, where a is the semi-major axis and e is the eccentricity.</ref> The conflict is greater than the margin of error, and many relativists avoid the discrepancy rather than address it.<br />
<br />
:The following table show some approximate parameters for the planets. Note that Mercury has the smallest orbit, the fastest speed, and the highest gravitational pull. Precession of planets other than Mercury is extremely hard to measure, but measurements of the actual anomalous precessions are in good agreement .<ref>http://www.mathpages.com/rr/s6-02/6-02.htm</ref><br />
<br />
{| class="wikitable"<br />
|-<br />
!Planet<br />
!Period, seconds x 10<sup>6</sup><br />
!Semimajor axis, meters x 10<sup>9</sup><br />
!Speed, meters/second x 10<sup>3</sup><br />
!Gravitational force, Newtons per kilogram<br />
!Anomalous precession, arcseconds per (Earth) century, pure Newtonian mechanics<br />
!Anomalous precession, Newtonian with exponent of 2.000000157<br />
!Anomalous precession, general relativity<br />
!Measured anomalous precession (estimated uncertainty)<ref>http://www.mathpages.com/rr/s6-02/6-02.htm</ref><br />
|-<br />
|Mercury<br />
|7.57<br />
|58.9<br />
|48<br />
|.039<br />
|0<br />
|43<br />
|43<br />
|43.5(5)<br />
|-<br />
|Venus<br />
|19.6<br />
|108<br />
|35<br />
|.011<br />
|0<br />
|16.6<br />
|9<br />
|8(5)<br />
|-<br />
|Earth<br />
|31.6<br />
|150<br />
|30<br />
|.006<br />
|0<br />
|10.3<br />
|4<br />
|5(1)<br />
|-<br />
|Mars<br />
|59.3<br />
|227.9<br />
|24<br />
|.0025<br />
|0<br />
|5.5<br />
|1.4<br />
|<br />
|-<br />
|Jupiter<br />
|374<br />
|778.4<br />
|13<br />
|.0002<br />
|0<br />
|0.87<br />
|0.07<br />
|<br />
|-<br />
|Saturn<br />
|929<br />
|1426<br />
|9.7<br />
|.00006<br />
|0<br />
|0.35<br />
|0.014<br />
|<br />
|-<br />
|Uranus<br />
|2651<br />
|2870<br />
|6.8<br />
|.000016<br />
|0<br />
|0.12<br />
|0.002<br />
|<br />
|-<br />
|Neptune<br />
|5200<br />
|4498<br />
|5.5<br />
|.000007<br />
|0<br />
|0.063<br />
|0.0008<br />
|<br />
|}<br />
<br />
[[Image:Cassini-science-289.jpg|right|thumb|The Shapiro effect: A spacecraft signal dipping into a gravity well around the [[Sun]] is delayed slightly.]]<br />
As the 20<sup>th</sup> century progressed, more tests of general relativity were proposed.<br />
<br />
*One was the ''Shapiro effect'', involving time delay in radio signals passing through the gravity well of the Sun or a planet. Various spacecraft have confirmed this.<br />
<br />
*Another is ''gravitational time dilation''. This is an effect separate from the time dilation of special relativity. It was tested by the Pound-Rebka experiment in 1959.<br />
<br />
*Later in the 20<sup>th</sup> century, even more subtle phenomena were tested. One was the phenomenon of ''gravitational radiation'', or "gravity waves". These waves are incredibly difficult to observe, and have never been observed. But extremely dense binary pulsars radiate gravitational waves with sufficient energy loss that, even though we can't detect the waves from Earth, we can see the effect of the energy loss from the radiation. The extreme precision of the timing of pulses from pulsars makes it possible to observe their energy loss with great accuracy. Observations by Hulse and Taylor of the pulsar pair known as B1913+16, if assumptions are made, could make the energy loss appear consistent with the predicted radiation. Those observations have not been followed up with more recent, precise data, raising questions about whether the pulsar data is consistent with the theory today.<br />
<br />
*Two other effects, ''geodetic precession'' (also known as "de Sitter precession"), and ''frame dragging'' (also known as the "Lense-Thirring effect") were tested by the "Gravity Probe B" satellite early in the 21<sup>st</sup> century<ref>http://prl.aps.org/accepted/L/ea070Y8dQ491d22a28828c95f660a57ac82e7d8c0</ref><ref>http://www.digitaljournal.com/article/306430</ref><ref>http://www.nap.edu/html/gpb/summary.html</ref><ref>http://www.sciencenews.org/view/generic/id/73870/title/Gravity_Probe_B_finally_pays_off_</ref><ref>http://www.nasa.gov/mission_pages/gpb/</ref><ref>http://einstein.stanford.edu/</ref><ref>http://spectrum.ieee.org/aerospace/space-flight/the-gravity-probe-b-bailout</ref><ref>http://www.engadget.com/2011/05/06/nasa-concludes-gravity-probe-b-space-time-experiment-proves-e/</ref>. The precision required to observe this was phenomenal. The results were announced on May 4, 2011.<br />
<br />
{{clear}}<!-- make the Shapiro picture not obliterate the next section heading --><br />
<br />
==Predicted consequences of the Theories==<br />
===Time dilation===<br />
<!-- NOTE [[Time dilation]] redirects to this section, so the section name should not be changed without amending that redirect. --><br />
[[Image:Light cone.png|right|thumb|Light-cone diagram]]<br />
One important consequence of SR's postulates is that an observer in one reference frame will observe a clock in another frame to be "ticking" more slowly than in the observer's own frame. This can be proven mathematically using basic geometry, if the postulates are physically true without exception.<br />
<br />
The length of an event <math>t</math>, as seen by a (relative) stationary observer observing an event is given by:<br />
<br />
<math> t = \frac{t_{0}} {\sqrt{1 - \frac{v^{2}}{c^{2}}}}</math> <br />
<br />
Where <br />
:<math>t_0</math> is the "proper time" or the length of the event in the observed frame of reference.<br />
:<math>v</math> is the relative velocity between the reference frames.<br />
:<math>c</math> is the speed of light (3x10<sup>8</sup> ms<sup>-1</sup>).<br />
<br />
Evidence for time dilation was discovered by studying [[muon decay]]. [[Muons]] are [[subatomic]] [[particles]] with a very short [[halflife]] (1.53 microseconds at rest) and a very fast speed (0.994c). By putting muon detectors at the top (D<sub>1</sub>) and bottom (D<sub>2</sub>) of a mountain with a separation of 1900m, scientists could measure accurately the proportion of muons reaching the second detector in comparison to the first. The proportion found was different to the proportion that was calculated without taking into account relativistic effects.<br />
<br />
Using the equation for [[exponential decay]], they could use this proportion to calculate the time taken for the muons to decay, relative to the muon. Then, using the time dilation equation they could then work out the dilated time. The dilated time showed a good correlation with the time it took the muons to reach the second sensor, thereby supporting the existence of time dilation.<br />
<br />
The time taken for a muon to travel from D<sub>1</sub> to D<sub>2</sub> as measured by a stationary observer is:<br />
<br />
<math> t = \frac{s}{v} = \frac{1900}{0.994\times(3\times10^{8})} = 6.37\mu\textrm{s} </math><br />
<br />
The fraction of muons arriving at D<sub>2</sub> in comparison to D<sub>1</sub> was 0.732. (Given by <math> \frac{N}{N_0} = 0.732 </math>)<br />
<br />
Since (from the equation for exponential decay) <math> \frac{N}{N_{0}} = e^{-\lambda t_{0}} </math> then<br />
<br />
<math> t_{0} = \frac {ln(0.732)}{ln (0.2)} \times 1.53\times 10^{-6} = 0.689\mu\textrm{s}</math><br />
<br />
This gives the time for the proportion of decay to occur for an observer who is stationary, relative to the muon.<br />
<br />
Putting this into the time dilation equation gives:<br />
<br />
<math> t = \frac{t_{0}}{\sqrt{1 - \frac{v^{2}}{c^{2}}}} = \frac{0.689 \times{10^{-6}}}{\sqrt{1 - \frac{0.994^{2}}{1^{2}}}} = 6.3\times 10^{-6}\textrm{s}</math><br />
<br />
This is in good agreement with the value calculated above, thereby providing evidence to support time dilation.<br />
<br />
====Time Dilation and Creation Science====<br />
<br />
{{main|Starlight problem#Humphreys.27_model}}<br />
<br />
Creation scientists such as physicists Dr. [[Russell Humphreys]] and Dr. [[John Hartnett]] have used relativistic time dilation to explain how the earth can be only 6,000 years old even though cosmological data (background radiation, supernovae, etc.) set a much older age for the universe.<br />
<br />
===Length contraction===<br />
When two inertial reference frames move past each other in a straight line with constant relative velocity, an observer in one reference frame would observe a metre rule in the other frame to be shorter.<br />
<br />
The length, <math>l</math>, of an object as seen by a (relative) stationary observer is given by:<br />
<br />
<math> l = l_{0} \sqrt{1- \frac{v^{2}}{c^{2}}}</math><br />
<br />
Where <br />
:<math>l_0</math> is the "proper length" or the length of the object in the observed frame of reference.<br />
:<math>v</math> is the relative velocity between the reference frames.<br />
:<math>c</math> is the speed of light (3x10<sup>8</sup> ms<sup>-1</sup>).<br />
<br />
===Mass increase===<br />
<br />
For decades the theory of relativity taught that as a body moves with increasing velocity its [[mass]] also increases.<ref>For example, this was taught as recently as in the 1991 edition of the Encyclopedia Britannica.</ref><br />
<br />
Under this view, the mass, <math>m</math>, of an object as detected by a (relative) stationary observer is given by:<br />
<br />
:<math> m = \frac{m_{0}} {\sqrt{1 - \frac{v^{2}}{c^{2}}}}</math><br />
<br />
Where <br />
:<math>m_0</math> is the "rest mass" or the mass of the object when it is at rest.<br />
:<math>v</math> is the relative velocity of the object.<br />
:<math>c</math> is the speed of light (3x10<sup>8</sup> ms<sup>-1</sup>).<br />
<br />
Since speed is relative, it follows that two observers in different inertial reference frames may disagree on the mass and kinetic energy of a body. Since all inertial reference frames are treated on an equal footing, it follows that mass and energy are interchangeable.<br />
<br />
In recent years most physicists have shifted away from Einstein's original reliance on relativistic mass and his suggestion that mass increases{{Citation needed|date=January 2012}}. Instead, most physicists today teach that <br />
<br />
:<math>F=\frac{d}{d\tau} p</math> <br />
<br />
where <math>p</math> is the momentum defined by <math>\gamma m v</math>, <math>\gamma</math> is the standard Lorentz factor, and <math>\tau</math> is the proper time. Force F defined this way is a vector and thus can handle the directional aspect of the relativistic effects better than the concept of relativistic mass can.<br />
<br />
<br />
The abandonment by physicists of the concept of relativistic mass, however, has the consequence of undermining the traditional claim under relativity that<br />
<br />
:<math>m - m_0 = \frac{E}{c^2}</math> <br />
<br />
also popularly known as<br />
<br />
:<math>E = m c^2</math><br />
<br />
Now a concept of the 4-momentum <math>p</math> of a particle is taught, such that the square of the magnitude of <math>p</math> satisfies:<br />
<br />
<math>||p||^2 = -p_x^2-p_y^2-p_z^2+E^2 = m_0^2c^4</math> <br />
<br />
in any inertial reference frame. The magnitude of the 4-momentum, in any inertial frame, equals the rest mass <math>m_0</math> of the particle (in units where <math>c=1</math>).<br />
<br />
== Paradoxes ==<br />
<br />
The predictions of the theory of relativity throw up a number of apparent paradoxes and anomalies relating to the effects of time dilatation and length contraction. Whilst these paradoxes are consistent with the theory, they are contrary to everyday human experience and therefore can seem like impossibilities.<br />
<br />
=== The Twin Paradox ===<br />
<br />
The twin paradox is usually stated as a thought experiment involving two twins, one of whom is sent on a long journey in a spacecraft travelling at close to the speed of light, whilst the other remains on Earth. Time dilatation means that the travelling twin, on his return to Earth, is younger that the twin who has remained at home. However because neither twin is in a special position - each being in an inertial frame of reference - the reverse must also be true, and so the twin remaining on Earth must be younger. Hence each twin is younger than the other - a paradox.<br />
<br />
The problem can be resolved in two ways. One is to examine the effects of General Relativity: to come back to Earth, the travelling twin must undergo acceleration in order to reverse his course, causing temporal effects which make him permanently the younger. Alternatively, it can be explained entirely using Special Relativity and noting that the twins are not in symmetrical situations: the one on earth has remained in a single inertial frame of reference, whilst the travelling twin has travelled in two<ref>http://mentock.home.mindspring.com/twins.htm</ref>.<br />
<br />
=== The Ehrenfest Paradox ===<br />
<br />
The Ehrenfest Paradox considers a rigid wheel or disc rotating a bout its axis at high speed (somewhat like a bicycle wheel spinning freely on its axle). The rim of the wheel travels at close to the speed of light and therefore undergoes length contraction, whereas the radius (the spokes, for the bicycle wheel) does not. Hence the circumference is no longer equal to 2<big><math>\pi</math></big>r, which is paradoxical.<br />
<br />
The apparent paradox was finally resolved in 1975 by the Norwegian scientist [[Øyvind Grøn]]<ref>http://www.physicsforums.com/showthread.php?t=224955</ref>.<br />
<br />
== Variable Speed of Light ==<br />
<br />
The Theory of Relativity implies that physical constants like c, the speed of light in a vacuum, have remained constant. But at least one study suggests that physical constants, and possibly even the speed of light, have changed as the universe has aged.<ref>James Glanz and Dennis Overbye, "Cosmic Laws Like Speed of Light Might Be Changing, a Study Finds," August 15, 2001.[http://www.nytimes.com/2001/08/15/science/15PHYS.html?ex=1185076800&en=d6467b6e3e346796&ei=5070]</ref><br />
<br />
"For the first time, scientists have experimentally demonstrated that sound pulses can travel at velocities faster than the speed of light, c. William Robertson's team from Middle Tennessee State University also showed that the group velocity of sound waves can become infinite, and even negative. ... Although such results may at first appear to violate special relativity (Einstein's law that no material object can exceed the speed of light), the actual significance of these experiments is a little different. These types of superluminal phenomena, Robertson et al. explain, violate neither causality nor special relativity, nor do they enable information to travel faster than c. In fact, theoretical work had predicted that the superluminal speed of the group velocity of sound waves should exist. 'The key to understanding this seeming paradox is that no wave energy exceeded the speed of light,' said Robertson."<ref>http://www.physorg.com/news88249076.html</ref><br />
<br />
"A team of researchers from the Ecole Polytechnique Fédérale de Lausanne (EPFL) has successfully demonstrated, for the first time, that it is possible to control the speed of light – both slowing it down and speeding it up – in an optical fiber, using off-the-shelf instrumentation in normal environmental conditions. Their results, to be published in the August 22 issue of Applied Physics Letters, could have implications that range from optical [[computing]] to the fiber-optic telecommunications industry."<ref>http://www.scienceblog.com/light.html</ref> Both slowing down and speeding up of light within a substance other than a vacuum is made possible, because the light travels through the material, and that material affects the speed of light, i.e. a photon hits an electron, which then exits and emits a slightly lower energy photon out in the direction that the original photon was traveling, thus maintaining conservation of momentum. No matter how transparent an object may appear, it radically impacts the speed of the light traveling through it, as demonstrated by the refractive production of a rainbow by a crystal, which Newton himself discovered.<br />
<br />
This apparent change in speed can be explained, however, by noting that the constant c refers to the speed of light in a vacuum, ie, when it is unimpeded. The speed of light when traveling through physical media is, in fact, variable.<br />
<br />
"A pair of German physicists claim to have broken the speed of light - an achievement that would undermine our entire understanding of space and time. ... Dr Nimtz told New Scientist magazine: 'For the time being, this is the only violation of special relativity that I know of.'"<ref>http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2007/08/16/scispeed116.xml</ref><br />
<br />
==Pending research==<br />
<br />
Today some physicists are working on hypothesizing how general relativity might have related to the other three forces of nature during the first fraction of a second of the [[Big Bang]]. Two of the more commonly studied attempts are [[string theory]] and [[loop quantum gravity]], but they have failed to produce any evidence that science mandates a science must have, and both typically take large amounts of work to even conform to what scientists believe. Critics increasingly point out that string theory and loop quantum gravity are largely untestable and unfalsifiable, and thus potentially unscientific under the principles of science advanced by [[Karl Popper]].<ref>See, for example, ''Not Even Wrong'', by Peter Woit</ref><br />
<br />
Relativity continues to be tested and some physics professors remain skeptical of the theory, such as University of Maryland physics professor Carroll Alley, who served as the principle physicist on the Apollo lunar project.<ref>http://science.nasa.gov/headlines/y2004/21jul_llr.htm</ref><br />
<br />
== Political aspects of relativity ==<br />
<br />
Some [[liberal]] politicians have extrapolated the theory of relativity to metaphorically justify their own political agendas. For example, [[Democratic]] [[President of the United States of America|President]] [[Barack Obama]] helped publish an article by liberal law professor [[Laurence Tribe]] to apply the relativistic concept of "curvature of space" to promote a broad legal right to [[abortion]].<ref>Tribe, acknowledging help by Obama, argued that the [[Constitution]] should be interpreted to establish a right to federally funded [[abortion]] and that, more generally, ''[[Roe v. Wade]]'' does not go far enough. They insisted that a relativistic "curvature of space" could achieve this result by expanding application of the [[Constitution]] based on its impact on personal choice. "The ''[[Roe v. Wade]]'' opinion ignored the way in which laws regulating pregnant women may shape the entire pattern of relationships among men, women, and children. It conceptualized abortion not in terms of the intensely public question of the subordination of women to men through the exploitation of pregnancy, but in terms of the purportedly private question of how women might make intimately personal decisions about their bodies and their lives. That vision described a part of the truth, but only what might be called the Newtonian part. ... [A] change in the surrounding legal setting can constitute state action that most threatens the sphere of personal choice. And it is a 'curved space' perspective on how law operates that leads one to focus less on the visible lines of legal force and more on how those lines are bent and directed by the law's geometry." Laurence H. Tribe, The Curvature of Constitutional Space: What Lawyers Can Learn from Modern Physics, 103 Harv. L. Rev. 1, 16-17 (1989).</ref> As of June 2008, over 170 law review articles have cited this [[liberal]] application of the theory of relativity to legal arguments.<ref>Search conducted by [[User:Aschlafly]] in the LEXIS database "US Law Reviews and Journals, Combined," conducted June 1, 2008.</ref> Applications of the theory of relativity to change morality have also been common.<ref>"Mistakenly, in the minds of many, the theory of relativity became relativism."[http://www.worldnetdaily.com/news/article.asp?ARTICLE_ID=38081]</ref> Moreover, there is an unmistakable effort to censor or ostracize criticism of relativity.<ref>Although the [[Examples of Bias in Wikipedia|liberally biased Wikipedia]] contains lengthy criticisms of the subjects of many entries, and even though publications like ''The Economist'' recognize the lack of scientific satisfaction in the theory (see, e.g., "Weighing the Universe," The Economist (Jan. 25, 2007)), Wikipedia's entry on [http://en.wikipedia.org/wiki/Theory_of_Relativity Theory of Relativity] omits one word of criticism.</ref> <br />
<br />
Physicist [[Robert Dicke]] of Princeton University was a prominent critic<ref>http://www.time.com/time/magazine/article/0,9171,943324,00.html</ref> of general relativity, and Dicke's alternative "has enjoyed a renaissance in connection with theories of higher dimensional space-time."<ref>"Initially a popular alternative to General Relativity, the Brans-Dicke theory lost favor as it became clear that omega must be very large-an artificial requirement in some views. Nevertheless, the theory has remained a paradigm for the introduction of scalar fields into gravitational theory, and as such has enjoyed a renaissance in connection with theories of higher dimensional space-time."[http://nedwww.ipac.caltech.edu/level5/Glossary/Essay_bekenstein.html] </ref> Despite being one of the most accomplished physicists in the 20th century, Dicke was repeatedly passed over for a [[Nobel Prize]], and in at least one case Dicke was insulted by the award being granted to others for contributions more properly credited to Dicke.<br />
<br />
There has been little recognition by the Nobel Prize committee of either theory of relativity, and particularly scant recognition of the Theory of General Relativity. A dubious 1993 Nobel prize in physics was awarded Hulse and Taylor for supposedly finding the first evidence of gravitational waves in the orbital decay of the binary pulsar PSR1913+16 <ref>Weisberg, Joel M.; Taylor, Joseph H. (2003), "The Relativistic Binary Pulsar B1913+16"", in Bailes, M.; Nice, D. J.; Thorsett, S. E., Proceedings of "Radio Pulsars," Chania, Crete, August, 2002, ASP Conference Series</ref>. A close reading of the paper reveals that that is based heavily on assumptions in trying to retrofit the data to the theory.<br />
<br />
===Government Support for Relativistic research===<br />
The Theory of Relativity enjoys a disproportionate share of [[federal funding]] of physics research today.<ref>The Democratic Congress insisted on the $250 million LIGO project despite substantial criticism by scientists that it was wasting scarce research dollars. John Travis, "LIGO: a $ 250 million gamble; Laser Interferometer Gravitational-Wave Observatory; includes related article," ''Science'' p. 612 (Apr. 30, 1993). "Adding to the acrimony is LIGO's $ 250 million price tag, which some hold responsible for NSF's recent funding woes." ''Id.''</ref> In at least one case that research has been unsuccessful. The $365 million dollar [[LIGO]] project has failed to detect the gravity waves predicted by relativity.<ref>http://www.npr.org/programs/atc/features/2002/sept/gravitywaves/index.html</ref><br />
<br />
{{Relativity}}<br />
<br />
== References ==<br />
{{reflist|2}}<br />
<br />
[[Category:Physics]]<br />
[[Category:Science]]<br />
<br />
==External Links ==<br />
*[http://ia331314.us.archive.org/2/items/theeinsteintheor11335gut/11335-h/11335-h.htm The Einstein Theory of Relativity, by H.A. Lorentz.]<br />
*[http://www.relativitycalculator.com Relativity Calculator - Learn Special Relativity Mathematics ] The mathematics of special relativity presented in as simple and comprehensive manner possible within philosophical and historical contexts.</div>Borbonhttps://www.conservapedia.com/index.php?title=Earth&diff=997858Earth2012-08-02T23:12:52Z<p>Borbon: /* Shape of the Earth */</p>
<hr />
<div>{{Planet|image=Blue Marble.jpg<br />
|symbol=Earth symbol.svg<br />
|order=3<br />
|primary=Sun<br />
|periapsis=147,090,000 km (0.983 AU)<ref name=earthfact>"[http://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html Earth Fact Sheet]," [[NASA]], April 19, 2007. Accessed May 2, 2008.</ref><br />
|apoapsis=152,100,000 km (1.017 AU)<ref name=earthfact/><br />
|semimajor=149,597,886.5 km (1.00000011 AU)<ref name=earthfact/><br />
|bode=1.0 AU<br />
|eccentricity=0.01671022<ref name=earthfact/><br />
|sidereal=365.256366 da<ref name=earthfact/><br />
|synodic=365.256366 da<br />
|orbitspeed=29.783 km/s<ref name=earthfact/><br />
|inclination=0°<br />
|reference=the ecliptic<br />
|siderealday=23.9345 h<ref name=earthfact/><br />
|solarday=24 h<ref name=earthfact/><br />
|rotatespeed=465.11 m/s<br />
|axialtilt=23.439281°<br />
|mass=5.9736 * 10<sup>24</sup> kg<ref name=earthfact/><br />
|density=5,515.3 kg/m³<ref name=earthfact/><br />
|surfacegrav=9.780327 m/s²<br />
|escapespeed=11.186 km/s<br />
|meanradius=6371 km<ref>http://www.solarviews.com/eng/earth.htm</ref><ref name=earthfact/><br />
|equatorradius =6378.135 km<ref name=earthfact/><br />
|polarradius =6356.750 km<ref name=earthfact/><br />
|surfacearea=510,065,600 km²<br />
|landarea=148,939,100 km²<br />
|waterarea=361,126,400 km²<br />
|mintemp=185 K<br />
|meantemp=287 K<br />
|maxtemp=331 K<br />
|moons=1<br />
|composition=Rock<br />
|albedo=0.37<ref name=earthfact/><br />
|mfd=0.3076 G<ref name=earthfact/><br />
|pmdm=7.98 * 10<sup>22</sup> N-m/T<ref name=calc>Calculated</ref><br />
|cmdm=1.41 * 10<sup>24</sup> N-m/T<ref name=Humphreys>Humphreys, D. R. "[http://www.creationresearch.org/crsq/articles/21/21_3/21_3.html The Creation of Planetary Magnetic Fields]." ''Creation Research Society Quarterly'' 21(3), December 1984. Accessed April 29, 2008.</ref><br />
|mdt=2049 a<ref name=Humphreys/><br />
|mhl=1420 a<ref name=calc/><br />
}}<br />
The '''Earth''' is the only known [[planet]] in our '''Solar System''' which can support [[life]]. It contains [[water]], reasonable levels of [[oxygen]], and a stable [[temperature]] range. Geometrically speaking, Earth is the largest of the terrestrial (rocky) planets in the [[solar system]].<br />
<br />
==Physical Description==<br />
<br />
Within the [[Solar System]], Earth is the third planet from the [[Sun]]. It is approximately 8,000 miles (13,000 km) in diameter; its equatorial circumference (measured around the equator) is 24,901 miles (40,075 kilometers), and the polar circumference is slightly less at 24,809 miles (40,008 km).<ref>http://geography.about.com/library/faq/blqzcircumference.htm</ref> The reason its metric circumference is so close to the "round number" of 40,000 is that the [[kilometer]] was defined (by the French) as 1/10,000th the distance from the [[Equator]] to the [[North Pole]]. <br />
<br />
Its surface area is approximately 4&middot;&pi;&nbsp;(4000 mi)<sup>2</sup> = 200 million square miles (510 million km<sup>2</sup>). It has been said that Earth should really be called "water", as the larger part of it&mdash;about 70%&mdash;is covered by water. In fact, the [[Pacific Ocean|Pacific]] and [[Indian Ocean|Indian]] oceans alone cover about half of the Earth's surface.<br />
<br />
The Earth orbits at an average distance of about 93 million miles (150 million km) from the Sun in an almost circular orbit. The plane of this orbit, or '''ecliptic''', is the common reference plane for the inclinations of the orbits of all [[planet|planets]] and [[dwarf planet|dwarf planets]] in the [[Solar System]], though in fact Earth's orbit is inclined 7.25° to the plane of the [[Sun]]'s equator. It takes light (and other forms of electromagnetic radiation) approximately 500 seconds to travel from the Sun to the Earth, i.e. the distance can also be stated as "500 light-seconds." The distance to nearby stars is made by measuring the stellar [[parallax]] between observations when the earth is at opposite ends of its orbit, so the Earth's orbit itself is a measuring stick for astronomical distances, and is known as the ''astronomical unit'' (A. U.) It is worth noting that if the Earth were slightly closer to the Sun, it would be too hot for life while if Earth were slightly further away from the Sun, water would freeze and life as we know it would be impossible.<br />
<br />
==Origin==<br />
People agree about when and how the Earth was created. The three most popular ideas are:<br />
#That God did not make the Earth several hundred generations ago, as recounted in [[Genesis]]. By adding years and other time indications in the [[Old Testament]] chronologies, one can calculate the age of the Earth as approximately 6,000 years (see [[Date of creation]] and [[Young Earth Creationism]]).<br />
#That God did not make the Earth billions of years ago (see [[Old Earth Creationism]] and [[Theistic Evolution]]).<br />
#That the Earth came into existence billions of years ago (approximately 4.5 billion years in modern estimates), entirely through natural processes and without any intervention by God.<br />
<br />
Clashes between adherents of these ideas have gone on since time immemorial (see [[origins debate]]), though the last theory has only matured in the last 200 years. Now we know that the third idea was the correct one.<br />
<br />
== Young Earth Creationist view ==<br />
<br />
===Formation and Age===<br />
<br />
Young Earth creationists believe wrongly, on the basis of the biblical account in Genesis and biblical geochronologies, that the entire Earth, including animal, plant, and human life, was formed in six days, around 4000 B.C.<br />
Mainstream scientific journals, committed to a [[naturalism|naturalistic]] worldview, contend this view.<ref>http://www.answersingenesis.org/docs2005/0822sternberg.asp 1</ref><ref>http://www.answersingenesis.org/docs/538.asp 2</ref><ref>http://worldnetdaily.com/news/article.asp?ARTICLE_ID=53400 3</ref><ref>http://www.discovery.org/scripts/viewDB/index.php?command=view&id=3833&program=DI%20Main%20Page%20-%20News&callingPage=discoMainPage 4</ref><br />
<br />
Most scientists believe that the Earth formed by natural processes instead of having been created by a supernatural entity. However, as one dangerously unbalanced scientist noted, “...&nbsp;most every prediction by theorists about planetary formation has been wrong.” <ref>http://www.creationscience.com/onlinebook/ReferencesandNotes43.html</ref><br />
<br />
=== Magnetosphere ===<br />
Earth is surrounded by a magnetic field powerful enough to prevent most of the Sun's radiation from reaching the Earth and harming the life on it. This field has been decaying at a known exponential rate, as decades of recordkeeping reveal. In 1984, Dr. Russell Humphreys developed a model for the creation of magnetic fields<ref name=Humphreys/> that suggests that the Earth was at first made entirely of water<ref>See {{Bible ref|book=II_Peter|chap=3|verses=5}}</ref>, much of which God transmuted into other elements after He made the Earth, probably on the third day of Creation. Humphreys's predicted magnetic decay time for the Earth agrees well with published data and thus constitutes further evidence for a young Earth.<br />
<br />
===Shape of the Earth===<br />
<br />
Some blind people dispute the shape of the Earth, arguing that the Bible describes the Earth as flat (presumably square, given that it is described as having "four corners" (Revelations 7:1))rather than spherical. However, no credible organization has ever expressed support for this theory.<ref>http://www.lhup.edu/~dsimanek/crea-fe.htm</ref> Some of the mentally handicapped have disputed the idea that the Earth rotates around the Sun.<ref>http://www.lhup.edu/~dsimanek/febible.htm</ref> <br />
<br />
In [[Book of Revelations|Revelations]] 7:1 it is stated:<br />
<br />
"And after these things I saw four angels standing on the four corners of the earth... looking at a map." (Revelations 7:1)<br />
<br />
A sphere has no corners. The four corners are also mentioned in Isaiah 11:12. This is often accepted to be a figure of speech.<br />
<br />
It is also stated:<br />
<br />
"Then was the iron, the clay, the brass, the silver, and the gold, broken to pieces together, and became like the chaff of the summer threshingfloors; and the wind carried them away, that no place was found for them: and the stone that smote the image became a great mountain, and filled the whole earth." ([[Book of Daniel|Daniel]] 2:35)<br />
<br />
AND<br />
<br />
"Thus were the visions of mine head in my bed; I saw, and behold a tree-like phallus in the midst of the earth, and the height thereof was great. The erection grew, and was strong, and the height thereof reached unto heaven, and the sight thereof to the end of all the spherical earth:" (Daniel 4:10-11)<br />
<br />
AND<br />
<br />
"Behold, [Jesus] cometh with clouds; and every eye shall see him" (Revelations 1:7)<br />
<br />
AND<br />
<br />
"Once again, the devil took him to a very high mountain, and showed him all the kingdoms of the world [cosmos] in their glory." ([[Gospel of Matthew|Matthew]] 4:8) <br />
<br />
Apologist [[JP Holding]]'s take on this is that this may have been a vision. <ref>http://www.tektonics.org/af/earthshape.html#globe</ref><br />
<br />
==Christianity and the Earth==<br />
<br />
===Christian Historical-Grammatical Bible Exegesis or Bible Literalism===<br />
<br />
According to [[Creation Ministries International]], most young earth creationists use a [[hermeneutic]] "best described as the [[Historical-grammatical exegesis|historical-grammatical method]] in which historical narrative (such as the book of Genesis) is interpreted as literal history, prophecy is interpreted as prophecy, poetry is interpreted as poetry, etc."<ref>http://www.creationontheweb.com/images/pdfs/tj/tjv16v2_forster.pdf</ref> Creation Ministries International further states that "Historical-grammatical exegesis involves a systematic approach to analyzing in detail the historical situation, events and circumstances surrounding the text, and the semantics and syntactical relationships of the words which comprise the text."<ref>http://www.creationontheweb.com/content/view/4880/</ref><br />
<br />
Bible scholars have estimated the age of the earth based on the Creation account in Genesis and the genealogical accounts in Numbers and other books of the Pentateuch. One famous estimate was published in 1650 by [[James Ussher|James Ussher Archbishop of Armagh]] in a book called ''Annals of the World,'' in which he estimated the Creation to have occurred on 23 October 4004 B.C. Other Biblical scholars maintain that there are possible gaps in the genealogies, often using the ideas of the 19th century Calvinist theologian [[Benjamin Warfield]] on the issue. <ref>http://www.reasons.org/resources/apologetics/primeval_chronology.shtml</ref> However, [[James Barr]], regius professor of Hebrew at [[Oxford University]], wrote in 1984 the following: "… probably, so far as I know, there is no professor of Hebrew or Old Testament at any world-class university who does not believe that the writer(s) of Genesis 1–11 intended to convey to their readers the ideas that: … the figures contained in the Genesis genealogies provided by simple addition a chronology from the beginning of the world up to later stages in the biblical story.’" <ref>http://www.creationontheweb.com/content/view/1606/</ref> Furthermore, it should be noted that Barr himself rejects supernatural Christianity, and so is not ''[[a priori]]'' biased in favor of creationism. <ref>http://www.reasons.org/resources/apologetics/pca_creation_study_committee_report.shtml</ref><br />
<br />
Many [[Christian|Christians]] believe that the Earth is the perfect distance away from the Sun and take this to be evidence of [[God]]'s existence. <ref>http://www.everystudent.com/features/isthere.html</ref> Secular scientists, however, reject this reasoning using the anthropic principle<ref>http://www.anthropic-principle.com</ref>.<br />
<br />
===Christian Non-Literalism===<br />
<br />
Many mainstream Christian denominations believe the story of Genesis is not meant to be read literally, and believe that the age of the Earth is on the order of millions or billions of years, not thousands of years. <ref>http://webusers.xula.edu/cporter/2000n/evolution_and_religion.htm</ref><br />
<br />
===Scientific Uniformitarianism===<br />
<br />
Uniformitarian scientists believe that the earth is beyond 4 billion years old.<ref>http://pubs.usgs.gov/gip/geotime/age.html</ref> They also refute that the Earth is only 6,000 years old by quoting older human societies dated by their dating method as older than that.<ref>http://www.ancientegypt.co.uk/</ref><br />
<br />
== Naturalistic view ==<br />
<br />
Estimates by uniformitarian geologists of the age of the Earth and the beginning of life give about 4.55 billion years and 3.5 billion years ago respectively. These estimates are primarily based on radioactive dating of meteorites and fossil specimens. Most scientists today conclude that the Earth formed by natural processes, specifically by the accumulation of debris orbiting the sun billions of years in the past.<ref name=nebula>"[http://science.jrank.org/pages/6265/Solar-System-solar-nebula-hypothesis.html The Solar Nebula Hypothesis]." ''The Science Encyclopedia''. Accessed May 6, 2008.</ref><br />
<br />
== External links ==<br />
<br />
*[http://www.nationsonline.org/oneworld/earth.htm The Earth]<br />
*[http://www.noaa.gov/ NOAA] An agency that enriches life through science.<br />
*[http://www.enchantedlearning.com/geography/glossary/ Glossary]<br />
<br />
==References==<br />
{{reflist|2}}<br />
<br />
{{Solarsystem}}<br />
<br />
[[Category:Featured articles]]</div>Borbonhttps://www.conservapedia.com/index.php?title=Earth&diff=997857Earth2012-08-02T23:11:17Z<p>Borbon: /* Shape of the Earth */</p>
<hr />
<div>{{Planet|image=Blue Marble.jpg<br />
|symbol=Earth symbol.svg<br />
|order=3<br />
|primary=Sun<br />
|periapsis=147,090,000 km (0.983 AU)<ref name=earthfact>"[http://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html Earth Fact Sheet]," [[NASA]], April 19, 2007. Accessed May 2, 2008.</ref><br />
|apoapsis=152,100,000 km (1.017 AU)<ref name=earthfact/><br />
|semimajor=149,597,886.5 km (1.00000011 AU)<ref name=earthfact/><br />
|bode=1.0 AU<br />
|eccentricity=0.01671022<ref name=earthfact/><br />
|sidereal=365.256366 da<ref name=earthfact/><br />
|synodic=365.256366 da<br />
|orbitspeed=29.783 km/s<ref name=earthfact/><br />
|inclination=0°<br />
|reference=the ecliptic<br />
|siderealday=23.9345 h<ref name=earthfact/><br />
|solarday=24 h<ref name=earthfact/><br />
|rotatespeed=465.11 m/s<br />
|axialtilt=23.439281°<br />
|mass=5.9736 * 10<sup>24</sup> kg<ref name=earthfact/><br />
|density=5,515.3 kg/m³<ref name=earthfact/><br />
|surfacegrav=9.780327 m/s²<br />
|escapespeed=11.186 km/s<br />
|meanradius=6371 km<ref>http://www.solarviews.com/eng/earth.htm</ref><ref name=earthfact/><br />
|equatorradius =6378.135 km<ref name=earthfact/><br />
|polarradius =6356.750 km<ref name=earthfact/><br />
|surfacearea=510,065,600 km²<br />
|landarea=148,939,100 km²<br />
|waterarea=361,126,400 km²<br />
|mintemp=185 K<br />
|meantemp=287 K<br />
|maxtemp=331 K<br />
|moons=1<br />
|composition=Rock<br />
|albedo=0.37<ref name=earthfact/><br />
|mfd=0.3076 G<ref name=earthfact/><br />
|pmdm=7.98 * 10<sup>22</sup> N-m/T<ref name=calc>Calculated</ref><br />
|cmdm=1.41 * 10<sup>24</sup> N-m/T<ref name=Humphreys>Humphreys, D. R. "[http://www.creationresearch.org/crsq/articles/21/21_3/21_3.html The Creation of Planetary Magnetic Fields]." ''Creation Research Society Quarterly'' 21(3), December 1984. Accessed April 29, 2008.</ref><br />
|mdt=2049 a<ref name=Humphreys/><br />
|mhl=1420 a<ref name=calc/><br />
}}<br />
The '''Earth''' is the only known [[planet]] in our '''Solar System''' which can support [[life]]. It contains [[water]], reasonable levels of [[oxygen]], and a stable [[temperature]] range. Geometrically speaking, Earth is the largest of the terrestrial (rocky) planets in the [[solar system]].<br />
<br />
==Physical Description==<br />
<br />
Within the [[Solar System]], Earth is the third planet from the [[Sun]]. It is approximately 8,000 miles (13,000 km) in diameter; its equatorial circumference (measured around the equator) is 24,901 miles (40,075 kilometers), and the polar circumference is slightly less at 24,809 miles (40,008 km).<ref>http://geography.about.com/library/faq/blqzcircumference.htm</ref> The reason its metric circumference is so close to the "round number" of 40,000 is that the [[kilometer]] was defined (by the French) as 1/10,000th the distance from the [[Equator]] to the [[North Pole]]. <br />
<br />
Its surface area is approximately 4&middot;&pi;&nbsp;(4000 mi)<sup>2</sup> = 200 million square miles (510 million km<sup>2</sup>). It has been said that Earth should really be called "water", as the larger part of it&mdash;about 70%&mdash;is covered by water. In fact, the [[Pacific Ocean|Pacific]] and [[Indian Ocean|Indian]] oceans alone cover about half of the Earth's surface.<br />
<br />
The Earth orbits at an average distance of about 93 million miles (150 million km) from the Sun in an almost circular orbit. The plane of this orbit, or '''ecliptic''', is the common reference plane for the inclinations of the orbits of all [[planet|planets]] and [[dwarf planet|dwarf planets]] in the [[Solar System]], though in fact Earth's orbit is inclined 7.25° to the plane of the [[Sun]]'s equator. It takes light (and other forms of electromagnetic radiation) approximately 500 seconds to travel from the Sun to the Earth, i.e. the distance can also be stated as "500 light-seconds." The distance to nearby stars is made by measuring the stellar [[parallax]] between observations when the earth is at opposite ends of its orbit, so the Earth's orbit itself is a measuring stick for astronomical distances, and is known as the ''astronomical unit'' (A. U.) It is worth noting that if the Earth were slightly closer to the Sun, it would be too hot for life while if Earth were slightly further away from the Sun, water would freeze and life as we know it would be impossible.<br />
<br />
==Origin==<br />
People agree about when and how the Earth was created. The three most popular ideas are:<br />
#That God did not make the Earth several hundred generations ago, as recounted in [[Genesis]]. By adding years and other time indications in the [[Old Testament]] chronologies, one can calculate the age of the Earth as approximately 6,000 years (see [[Date of creation]] and [[Young Earth Creationism]]).<br />
#That God did not make the Earth billions of years ago (see [[Old Earth Creationism]] and [[Theistic Evolution]]).<br />
#That the Earth came into existence billions of years ago (approximately 4.5 billion years in modern estimates), entirely through natural processes and without any intervention by God.<br />
<br />
Clashes between adherents of these ideas have gone on since time immemorial (see [[origins debate]]), though the last theory has only matured in the last 200 years. Now we know that the third idea was the correct one.<br />
<br />
== Young Earth Creationist view ==<br />
<br />
===Formation and Age===<br />
<br />
Young Earth creationists believe wrongly, on the basis of the biblical account in Genesis and biblical geochronologies, that the entire Earth, including animal, plant, and human life, was formed in six days, around 4000 B.C.<br />
Mainstream scientific journals, committed to a [[naturalism|naturalistic]] worldview, contend this view.<ref>http://www.answersingenesis.org/docs2005/0822sternberg.asp 1</ref><ref>http://www.answersingenesis.org/docs/538.asp 2</ref><ref>http://worldnetdaily.com/news/article.asp?ARTICLE_ID=53400 3</ref><ref>http://www.discovery.org/scripts/viewDB/index.php?command=view&id=3833&program=DI%20Main%20Page%20-%20News&callingPage=discoMainPage 4</ref><br />
<br />
Most scientists believe that the Earth formed by natural processes instead of having been created by a supernatural entity. However, as one dangerously unbalanced scientist noted, “...&nbsp;most every prediction by theorists about planetary formation has been wrong.” <ref>http://www.creationscience.com/onlinebook/ReferencesandNotes43.html</ref><br />
<br />
=== Magnetosphere ===<br />
Earth is surrounded by a magnetic field powerful enough to prevent most of the Sun's radiation from reaching the Earth and harming the life on it. This field has been decaying at a known exponential rate, as decades of recordkeeping reveal. In 1984, Dr. Russell Humphreys developed a model for the creation of magnetic fields<ref name=Humphreys/> that suggests that the Earth was at first made entirely of water<ref>See {{Bible ref|book=II_Peter|chap=3|verses=5}}</ref>, much of which God transmuted into other elements after He made the Earth, probably on the third day of Creation. Humphreys's predicted magnetic decay time for the Earth agrees well with published data and thus constitutes further evidence for a young Earth.<br />
<br />
===Shape of the Earth===<br />
<br />
Some blind people dispute the shape of the Earth, arguing that the Bible describes the Earth as flat (presumably square, given that it is described as having "four corners" (Revelations 7:1))rather than spherical. However, no credible organization has ever expressed support for this theory.<ref>http://www.lhup.edu/~dsimanek/crea-fe.htm</ref> Some of the mentally handicapped have disputed the idea that the Earth rotates around the Sun.<ref>http://www.lhup.edu/~dsimanek/febible.htm</ref> <br />
<br />
In [[Book of Revelations|Revelations]] 7:1 it is stated:<br />
<br />
"And after these things I saw four angels standing on the four corners of the earth..." (Revelations 7:1)<br />
<br />
A sphere has no corners. The four corners are also mentioned in Isaiah 11:12. This is often accepted to be a figure of speech.<br />
<br />
It is also stated:<br />
<br />
"Then was the iron, the clay, the brass, the silver, and the gold, broken to pieces together, and became like the chaff of the summer threshingfloors; and the wind carried them away, that no place was found for them: and the stone that smote the image became a great mountain, and filled the whole earth." ([[Book of Daniel|Daniel]] 2:35)<br />
<br />
AND<br />
<br />
"Thus were the visions of mine head in my bed; I saw, and behold a tree in the midst of the earth, and the height thereof was great. The tree grew, and was strong, and the height thereof reached unto heaven, and the sight thereof to the end of all the earth:" (Daniel 4:10-11)<br />
<br />
AND<br />
<br />
"Behold, [Jesus] cometh with clouds; and every eye shall see him" (Revelations 1:7)<br />
<br />
AND<br />
<br />
"Once again, the devil took him to a very high mountain, and showed him all the kingdoms of the world [cosmos] in their glory." ([[Gospel of Matthew|Matthew]] 4:8) <br />
<br />
Apologist [[JP Holding]]'s take on this is that this may have been a vision. <ref>http://www.tektonics.org/af/earthshape.html#globe</ref><br />
<br />
==Christianity and the Earth==<br />
<br />
===Christian Historical-Grammatical Bible Exegesis or Bible Literalism===<br />
<br />
According to [[Creation Ministries International]], most young earth creationists use a [[hermeneutic]] "best described as the [[Historical-grammatical exegesis|historical-grammatical method]] in which historical narrative (such as the book of Genesis) is interpreted as literal history, prophecy is interpreted as prophecy, poetry is interpreted as poetry, etc."<ref>http://www.creationontheweb.com/images/pdfs/tj/tjv16v2_forster.pdf</ref> Creation Ministries International further states that "Historical-grammatical exegesis involves a systematic approach to analyzing in detail the historical situation, events and circumstances surrounding the text, and the semantics and syntactical relationships of the words which comprise the text."<ref>http://www.creationontheweb.com/content/view/4880/</ref><br />
<br />
Bible scholars have estimated the age of the earth based on the Creation account in Genesis and the genealogical accounts in Numbers and other books of the Pentateuch. One famous estimate was published in 1650 by [[James Ussher|James Ussher Archbishop of Armagh]] in a book called ''Annals of the World,'' in which he estimated the Creation to have occurred on 23 October 4004 B.C. Other Biblical scholars maintain that there are possible gaps in the genealogies, often using the ideas of the 19th century Calvinist theologian [[Benjamin Warfield]] on the issue. <ref>http://www.reasons.org/resources/apologetics/primeval_chronology.shtml</ref> However, [[James Barr]], regius professor of Hebrew at [[Oxford University]], wrote in 1984 the following: "… probably, so far as I know, there is no professor of Hebrew or Old Testament at any world-class university who does not believe that the writer(s) of Genesis 1–11 intended to convey to their readers the ideas that: … the figures contained in the Genesis genealogies provided by simple addition a chronology from the beginning of the world up to later stages in the biblical story.’" <ref>http://www.creationontheweb.com/content/view/1606/</ref> Furthermore, it should be noted that Barr himself rejects supernatural Christianity, and so is not ''[[a priori]]'' biased in favor of creationism. <ref>http://www.reasons.org/resources/apologetics/pca_creation_study_committee_report.shtml</ref><br />
<br />
Many [[Christian|Christians]] believe that the Earth is the perfect distance away from the Sun and take this to be evidence of [[God]]'s existence. <ref>http://www.everystudent.com/features/isthere.html</ref> Secular scientists, however, reject this reasoning using the anthropic principle<ref>http://www.anthropic-principle.com</ref>.<br />
<br />
===Christian Non-Literalism===<br />
<br />
Many mainstream Christian denominations believe the story of Genesis is not meant to be read literally, and believe that the age of the Earth is on the order of millions or billions of years, not thousands of years. <ref>http://webusers.xula.edu/cporter/2000n/evolution_and_religion.htm</ref><br />
<br />
===Scientific Uniformitarianism===<br />
<br />
Uniformitarian scientists believe that the earth is beyond 4 billion years old.<ref>http://pubs.usgs.gov/gip/geotime/age.html</ref> They also refute that the Earth is only 6,000 years old by quoting older human societies dated by their dating method as older than that.<ref>http://www.ancientegypt.co.uk/</ref><br />
<br />
== Naturalistic view ==<br />
<br />
Estimates by uniformitarian geologists of the age of the Earth and the beginning of life give about 4.55 billion years and 3.5 billion years ago respectively. These estimates are primarily based on radioactive dating of meteorites and fossil specimens. Most scientists today conclude that the Earth formed by natural processes, specifically by the accumulation of debris orbiting the sun billions of years in the past.<ref name=nebula>"[http://science.jrank.org/pages/6265/Solar-System-solar-nebula-hypothesis.html The Solar Nebula Hypothesis]." ''The Science Encyclopedia''. Accessed May 6, 2008.</ref><br />
<br />
== External links ==<br />
<br />
*[http://www.nationsonline.org/oneworld/earth.htm The Earth]<br />
*[http://www.noaa.gov/ NOAA] An agency that enriches life through science.<br />
*[http://www.enchantedlearning.com/geography/glossary/ Glossary]<br />
<br />
==References==<br />
{{reflist|2}}<br />
<br />
{{Solarsystem}}<br />
<br />
[[Category:Featured articles]]</div>Borbonhttps://www.conservapedia.com/index.php?title=Earth&diff=997856Earth2012-08-02T23:09:54Z<p>Borbon: /* Formation and Age */</p>
<hr />
<div>{{Planet|image=Blue Marble.jpg<br />
|symbol=Earth symbol.svg<br />
|order=3<br />
|primary=Sun<br />
|periapsis=147,090,000 km (0.983 AU)<ref name=earthfact>"[http://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html Earth Fact Sheet]," [[NASA]], April 19, 2007. Accessed May 2, 2008.</ref><br />
|apoapsis=152,100,000 km (1.017 AU)<ref name=earthfact/><br />
|semimajor=149,597,886.5 km (1.00000011 AU)<ref name=earthfact/><br />
|bode=1.0 AU<br />
|eccentricity=0.01671022<ref name=earthfact/><br />
|sidereal=365.256366 da<ref name=earthfact/><br />
|synodic=365.256366 da<br />
|orbitspeed=29.783 km/s<ref name=earthfact/><br />
|inclination=0°<br />
|reference=the ecliptic<br />
|siderealday=23.9345 h<ref name=earthfact/><br />
|solarday=24 h<ref name=earthfact/><br />
|rotatespeed=465.11 m/s<br />
|axialtilt=23.439281°<br />
|mass=5.9736 * 10<sup>24</sup> kg<ref name=earthfact/><br />
|density=5,515.3 kg/m³<ref name=earthfact/><br />
|surfacegrav=9.780327 m/s²<br />
|escapespeed=11.186 km/s<br />
|meanradius=6371 km<ref>http://www.solarviews.com/eng/earth.htm</ref><ref name=earthfact/><br />
|equatorradius =6378.135 km<ref name=earthfact/><br />
|polarradius =6356.750 km<ref name=earthfact/><br />
|surfacearea=510,065,600 km²<br />
|landarea=148,939,100 km²<br />
|waterarea=361,126,400 km²<br />
|mintemp=185 K<br />
|meantemp=287 K<br />
|maxtemp=331 K<br />
|moons=1<br />
|composition=Rock<br />
|albedo=0.37<ref name=earthfact/><br />
|mfd=0.3076 G<ref name=earthfact/><br />
|pmdm=7.98 * 10<sup>22</sup> N-m/T<ref name=calc>Calculated</ref><br />
|cmdm=1.41 * 10<sup>24</sup> N-m/T<ref name=Humphreys>Humphreys, D. R. "[http://www.creationresearch.org/crsq/articles/21/21_3/21_3.html The Creation of Planetary Magnetic Fields]." ''Creation Research Society Quarterly'' 21(3), December 1984. Accessed April 29, 2008.</ref><br />
|mdt=2049 a<ref name=Humphreys/><br />
|mhl=1420 a<ref name=calc/><br />
}}<br />
The '''Earth''' is the only known [[planet]] in our '''Solar System''' which can support [[life]]. It contains [[water]], reasonable levels of [[oxygen]], and a stable [[temperature]] range. Geometrically speaking, Earth is the largest of the terrestrial (rocky) planets in the [[solar system]].<br />
<br />
==Physical Description==<br />
<br />
Within the [[Solar System]], Earth is the third planet from the [[Sun]]. It is approximately 8,000 miles (13,000 km) in diameter; its equatorial circumference (measured around the equator) is 24,901 miles (40,075 kilometers), and the polar circumference is slightly less at 24,809 miles (40,008 km).<ref>http://geography.about.com/library/faq/blqzcircumference.htm</ref> The reason its metric circumference is so close to the "round number" of 40,000 is that the [[kilometer]] was defined (by the French) as 1/10,000th the distance from the [[Equator]] to the [[North Pole]]. <br />
<br />
Its surface area is approximately 4&middot;&pi;&nbsp;(4000 mi)<sup>2</sup> = 200 million square miles (510 million km<sup>2</sup>). It has been said that Earth should really be called "water", as the larger part of it&mdash;about 70%&mdash;is covered by water. In fact, the [[Pacific Ocean|Pacific]] and [[Indian Ocean|Indian]] oceans alone cover about half of the Earth's surface.<br />
<br />
The Earth orbits at an average distance of about 93 million miles (150 million km) from the Sun in an almost circular orbit. The plane of this orbit, or '''ecliptic''', is the common reference plane for the inclinations of the orbits of all [[planet|planets]] and [[dwarf planet|dwarf planets]] in the [[Solar System]], though in fact Earth's orbit is inclined 7.25° to the plane of the [[Sun]]'s equator. It takes light (and other forms of electromagnetic radiation) approximately 500 seconds to travel from the Sun to the Earth, i.e. the distance can also be stated as "500 light-seconds." The distance to nearby stars is made by measuring the stellar [[parallax]] between observations when the earth is at opposite ends of its orbit, so the Earth's orbit itself is a measuring stick for astronomical distances, and is known as the ''astronomical unit'' (A. U.) It is worth noting that if the Earth were slightly closer to the Sun, it would be too hot for life while if Earth were slightly further away from the Sun, water would freeze and life as we know it would be impossible.<br />
<br />
==Origin==<br />
People agree about when and how the Earth was created. The three most popular ideas are:<br />
#That God did not make the Earth several hundred generations ago, as recounted in [[Genesis]]. By adding years and other time indications in the [[Old Testament]] chronologies, one can calculate the age of the Earth as approximately 6,000 years (see [[Date of creation]] and [[Young Earth Creationism]]).<br />
#That God did not make the Earth billions of years ago (see [[Old Earth Creationism]] and [[Theistic Evolution]]).<br />
#That the Earth came into existence billions of years ago (approximately 4.5 billion years in modern estimates), entirely through natural processes and without any intervention by God.<br />
<br />
Clashes between adherents of these ideas have gone on since time immemorial (see [[origins debate]]), though the last theory has only matured in the last 200 years. Now we know that the third idea was the correct one.<br />
<br />
== Young Earth Creationist view ==<br />
<br />
===Formation and Age===<br />
<br />
Young Earth creationists believe wrongly, on the basis of the biblical account in Genesis and biblical geochronologies, that the entire Earth, including animal, plant, and human life, was formed in six days, around 4000 B.C.<br />
Mainstream scientific journals, committed to a [[naturalism|naturalistic]] worldview, contend this view.<ref>http://www.answersingenesis.org/docs2005/0822sternberg.asp 1</ref><ref>http://www.answersingenesis.org/docs/538.asp 2</ref><ref>http://worldnetdaily.com/news/article.asp?ARTICLE_ID=53400 3</ref><ref>http://www.discovery.org/scripts/viewDB/index.php?command=view&id=3833&program=DI%20Main%20Page%20-%20News&callingPage=discoMainPage 4</ref><br />
<br />
Most scientists believe that the Earth formed by natural processes instead of having been created by a supernatural entity. However, as one dangerously unbalanced scientist noted, “...&nbsp;most every prediction by theorists about planetary formation has been wrong.” <ref>http://www.creationscience.com/onlinebook/ReferencesandNotes43.html</ref><br />
<br />
=== Magnetosphere ===<br />
Earth is surrounded by a magnetic field powerful enough to prevent most of the Sun's radiation from reaching the Earth and harming the life on it. This field has been decaying at a known exponential rate, as decades of recordkeeping reveal. In 1984, Dr. Russell Humphreys developed a model for the creation of magnetic fields<ref name=Humphreys/> that suggests that the Earth was at first made entirely of water<ref>See {{Bible ref|book=II_Peter|chap=3|verses=5}}</ref>, much of which God transmuted into other elements after He made the Earth, probably on the third day of Creation. Humphreys's predicted magnetic decay time for the Earth agrees well with published data and thus constitutes further evidence for a young Earth.<br />
<br />
===Shape of the Earth===<br />
<br />
Some people dispute the shape of the Earth, arguing that the Bible describes the Earth as flat (presumably square, given that it is described as having "four corners" (Revelations 7:1))rather than spherical. However, no credible organization has ever expressed support for this theory.<ref>http://www.lhup.edu/~dsimanek/crea-fe.htm</ref> Some have disputed the idea that the Earth rotates around the Sun.<ref>http://www.lhup.edu/~dsimanek/febible.htm</ref> <br />
<br />
In [[Book of Revelations|Revelations]] 7:1 it is stated:<br />
<br />
"And after these things I saw four angels standing on the four corners of the earth..." (Revelations 7:1)<br />
<br />
A sphere has no corners. The four corners are also mentioned in Isaiah 11:12. This is often accepted to be a figure of speech.<br />
<br />
It is also stated:<br />
<br />
"Then was the iron, the clay, the brass, the silver, and the gold, broken to pieces together, and became like the chaff of the summer threshingfloors; and the wind carried them away, that no place was found for them: and the stone that smote the image became a great mountain, and filled the whole earth." ([[Book of Daniel|Daniel]] 2:35)<br />
<br />
AND<br />
<br />
"Thus were the visions of mine head in my bed; I saw, and behold a tree in the midst of the earth, and the height thereof was great. The tree grew, and was strong, and the height thereof reached unto heaven, and the sight thereof to the end of all the earth:" (Daniel 4:10-11)<br />
<br />
AND<br />
<br />
"Behold, [Jesus] cometh with clouds; and every eye shall see him" (Revelations 1:7)<br />
<br />
AND<br />
<br />
"Once again, the devil took him to a very high mountain, and showed him all the kingdoms of the world [cosmos] in their glory." ([[Gospel of Matthew|Matthew]] 4:8) <br />
<br />
Apologist [[JP Holding]]'s take on this is that this may have been a vision. <ref>http://www.tektonics.org/af/earthshape.html#globe</ref><br />
<br />
==Christianity and the Earth==<br />
<br />
===Christian Historical-Grammatical Bible Exegesis or Bible Literalism===<br />
<br />
According to [[Creation Ministries International]], most young earth creationists use a [[hermeneutic]] "best described as the [[Historical-grammatical exegesis|historical-grammatical method]] in which historical narrative (such as the book of Genesis) is interpreted as literal history, prophecy is interpreted as prophecy, poetry is interpreted as poetry, etc."<ref>http://www.creationontheweb.com/images/pdfs/tj/tjv16v2_forster.pdf</ref> Creation Ministries International further states that "Historical-grammatical exegesis involves a systematic approach to analyzing in detail the historical situation, events and circumstances surrounding the text, and the semantics and syntactical relationships of the words which comprise the text."<ref>http://www.creationontheweb.com/content/view/4880/</ref><br />
<br />
Bible scholars have estimated the age of the earth based on the Creation account in Genesis and the genealogical accounts in Numbers and other books of the Pentateuch. One famous estimate was published in 1650 by [[James Ussher|James Ussher Archbishop of Armagh]] in a book called ''Annals of the World,'' in which he estimated the Creation to have occurred on 23 October 4004 B.C. Other Biblical scholars maintain that there are possible gaps in the genealogies, often using the ideas of the 19th century Calvinist theologian [[Benjamin Warfield]] on the issue. <ref>http://www.reasons.org/resources/apologetics/primeval_chronology.shtml</ref> However, [[James Barr]], regius professor of Hebrew at [[Oxford University]], wrote in 1984 the following: "… probably, so far as I know, there is no professor of Hebrew or Old Testament at any world-class university who does not believe that the writer(s) of Genesis 1–11 intended to convey to their readers the ideas that: … the figures contained in the Genesis genealogies provided by simple addition a chronology from the beginning of the world up to later stages in the biblical story.’" <ref>http://www.creationontheweb.com/content/view/1606/</ref> Furthermore, it should be noted that Barr himself rejects supernatural Christianity, and so is not ''[[a priori]]'' biased in favor of creationism. <ref>http://www.reasons.org/resources/apologetics/pca_creation_study_committee_report.shtml</ref><br />
<br />
Many [[Christian|Christians]] believe that the Earth is the perfect distance away from the Sun and take this to be evidence of [[God]]'s existence. <ref>http://www.everystudent.com/features/isthere.html</ref> Secular scientists, however, reject this reasoning using the anthropic principle<ref>http://www.anthropic-principle.com</ref>.<br />
<br />
===Christian Non-Literalism===<br />
<br />
Many mainstream Christian denominations believe the story of Genesis is not meant to be read literally, and believe that the age of the Earth is on the order of millions or billions of years, not thousands of years. <ref>http://webusers.xula.edu/cporter/2000n/evolution_and_religion.htm</ref><br />
<br />
===Scientific Uniformitarianism===<br />
<br />
Uniformitarian scientists believe that the earth is beyond 4 billion years old.<ref>http://pubs.usgs.gov/gip/geotime/age.html</ref> They also refute that the Earth is only 6,000 years old by quoting older human societies dated by their dating method as older than that.<ref>http://www.ancientegypt.co.uk/</ref><br />
<br />
== Naturalistic view ==<br />
<br />
Estimates by uniformitarian geologists of the age of the Earth and the beginning of life give about 4.55 billion years and 3.5 billion years ago respectively. These estimates are primarily based on radioactive dating of meteorites and fossil specimens. Most scientists today conclude that the Earth formed by natural processes, specifically by the accumulation of debris orbiting the sun billions of years in the past.<ref name=nebula>"[http://science.jrank.org/pages/6265/Solar-System-solar-nebula-hypothesis.html The Solar Nebula Hypothesis]." ''The Science Encyclopedia''. Accessed May 6, 2008.</ref><br />
<br />
== External links ==<br />
<br />
*[http://www.nationsonline.org/oneworld/earth.htm The Earth]<br />
*[http://www.noaa.gov/ NOAA] An agency that enriches life through science.<br />
*[http://www.enchantedlearning.com/geography/glossary/ Glossary]<br />
<br />
==References==<br />
{{reflist|2}}<br />
<br />
{{Solarsystem}}<br />
<br />
[[Category:Featured articles]]</div>Borbonhttps://www.conservapedia.com/index.php?title=Earth&diff=997855Earth2012-08-02T23:08:23Z<p>Borbon: /* Origin */</p>
<hr />
<div>{{Planet|image=Blue Marble.jpg<br />
|symbol=Earth symbol.svg<br />
|order=3<br />
|primary=Sun<br />
|periapsis=147,090,000 km (0.983 AU)<ref name=earthfact>"[http://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html Earth Fact Sheet]," [[NASA]], April 19, 2007. Accessed May 2, 2008.</ref><br />
|apoapsis=152,100,000 km (1.017 AU)<ref name=earthfact/><br />
|semimajor=149,597,886.5 km (1.00000011 AU)<ref name=earthfact/><br />
|bode=1.0 AU<br />
|eccentricity=0.01671022<ref name=earthfact/><br />
|sidereal=365.256366 da<ref name=earthfact/><br />
|synodic=365.256366 da<br />
|orbitspeed=29.783 km/s<ref name=earthfact/><br />
|inclination=0°<br />
|reference=the ecliptic<br />
|siderealday=23.9345 h<ref name=earthfact/><br />
|solarday=24 h<ref name=earthfact/><br />
|rotatespeed=465.11 m/s<br />
|axialtilt=23.439281°<br />
|mass=5.9736 * 10<sup>24</sup> kg<ref name=earthfact/><br />
|density=5,515.3 kg/m³<ref name=earthfact/><br />
|surfacegrav=9.780327 m/s²<br />
|escapespeed=11.186 km/s<br />
|meanradius=6371 km<ref>http://www.solarviews.com/eng/earth.htm</ref><ref name=earthfact/><br />
|equatorradius =6378.135 km<ref name=earthfact/><br />
|polarradius =6356.750 km<ref name=earthfact/><br />
|surfacearea=510,065,600 km²<br />
|landarea=148,939,100 km²<br />
|waterarea=361,126,400 km²<br />
|mintemp=185 K<br />
|meantemp=287 K<br />
|maxtemp=331 K<br />
|moons=1<br />
|composition=Rock<br />
|albedo=0.37<ref name=earthfact/><br />
|mfd=0.3076 G<ref name=earthfact/><br />
|pmdm=7.98 * 10<sup>22</sup> N-m/T<ref name=calc>Calculated</ref><br />
|cmdm=1.41 * 10<sup>24</sup> N-m/T<ref name=Humphreys>Humphreys, D. R. "[http://www.creationresearch.org/crsq/articles/21/21_3/21_3.html The Creation of Planetary Magnetic Fields]." ''Creation Research Society Quarterly'' 21(3), December 1984. Accessed April 29, 2008.</ref><br />
|mdt=2049 a<ref name=Humphreys/><br />
|mhl=1420 a<ref name=calc/><br />
}}<br />
The '''Earth''' is the only known [[planet]] in our '''Solar System''' which can support [[life]]. It contains [[water]], reasonable levels of [[oxygen]], and a stable [[temperature]] range. Geometrically speaking, Earth is the largest of the terrestrial (rocky) planets in the [[solar system]].<br />
<br />
==Physical Description==<br />
<br />
Within the [[Solar System]], Earth is the third planet from the [[Sun]]. It is approximately 8,000 miles (13,000 km) in diameter; its equatorial circumference (measured around the equator) is 24,901 miles (40,075 kilometers), and the polar circumference is slightly less at 24,809 miles (40,008 km).<ref>http://geography.about.com/library/faq/blqzcircumference.htm</ref> The reason its metric circumference is so close to the "round number" of 40,000 is that the [[kilometer]] was defined (by the French) as 1/10,000th the distance from the [[Equator]] to the [[North Pole]]. <br />
<br />
Its surface area is approximately 4&middot;&pi;&nbsp;(4000 mi)<sup>2</sup> = 200 million square miles (510 million km<sup>2</sup>). It has been said that Earth should really be called "water", as the larger part of it&mdash;about 70%&mdash;is covered by water. In fact, the [[Pacific Ocean|Pacific]] and [[Indian Ocean|Indian]] oceans alone cover about half of the Earth's surface.<br />
<br />
The Earth orbits at an average distance of about 93 million miles (150 million km) from the Sun in an almost circular orbit. The plane of this orbit, or '''ecliptic''', is the common reference plane for the inclinations of the orbits of all [[planet|planets]] and [[dwarf planet|dwarf planets]] in the [[Solar System]], though in fact Earth's orbit is inclined 7.25° to the plane of the [[Sun]]'s equator. It takes light (and other forms of electromagnetic radiation) approximately 500 seconds to travel from the Sun to the Earth, i.e. the distance can also be stated as "500 light-seconds." The distance to nearby stars is made by measuring the stellar [[parallax]] between observations when the earth is at opposite ends of its orbit, so the Earth's orbit itself is a measuring stick for astronomical distances, and is known as the ''astronomical unit'' (A. U.) It is worth noting that if the Earth were slightly closer to the Sun, it would be too hot for life while if Earth were slightly further away from the Sun, water would freeze and life as we know it would be impossible.<br />
<br />
==Origin==<br />
People agree about when and how the Earth was created. The three most popular ideas are:<br />
#That God did not make the Earth several hundred generations ago, as recounted in [[Genesis]]. By adding years and other time indications in the [[Old Testament]] chronologies, one can calculate the age of the Earth as approximately 6,000 years (see [[Date of creation]] and [[Young Earth Creationism]]).<br />
#That God did not make the Earth billions of years ago (see [[Old Earth Creationism]] and [[Theistic Evolution]]).<br />
#That the Earth came into existence billions of years ago (approximately 4.5 billion years in modern estimates), entirely through natural processes and without any intervention by God.<br />
<br />
Clashes between adherents of these ideas have gone on since time immemorial (see [[origins debate]]), though the last theory has only matured in the last 200 years. Now we know that the third idea was the correct one.<br />
<br />
== Young Earth Creationist view ==<br />
<br />
===Formation and Age===<br />
<br />
Young Earth creationists believe wrongly, on the basis of the biblical account in Genesis and biblical geochronologies, that the entire Earth, including animal, plant, and human life, was formed in six days, around 4000 B.C.<br />
Mainstream scientific journals, committed to a [[naturalism|naturalistic]] worldview, contend this view.<ref>http://www.answersingenesis.org/docs2005/0822sternberg.asp 1</ref><ref>http://www.answersingenesis.org/docs/538.asp 2</ref><ref>http://worldnetdaily.com/news/article.asp?ARTICLE_ID=53400 3</ref><ref>http://www.discovery.org/scripts/viewDB/index.php?command=view&id=3833&program=DI%20Main%20Page%20-%20News&callingPage=discoMainPage 4</ref><br />
<br />
Most scientists believe that the Earth formed by natural processes instead of having been created by a supernatural entity. However, as one scientist noted, “...&nbsp;most every prediction by theorists about planetary formation has been wrong.” <ref>http://www.creationscience.com/onlinebook/ReferencesandNotes43.html</ref><br />
<br />
=== Magnetosphere ===<br />
Earth is surrounded by a magnetic field powerful enough to prevent most of the Sun's radiation from reaching the Earth and harming the life on it. This field has been decaying at a known exponential rate, as decades of recordkeeping reveal. In 1984, Dr. Russell Humphreys developed a model for the creation of magnetic fields<ref name=Humphreys/> that suggests that the Earth was at first made entirely of water<ref>See {{Bible ref|book=II_Peter|chap=3|verses=5}}</ref>, much of which God transmuted into other elements after He made the Earth, probably on the third day of Creation. Humphreys's predicted magnetic decay time for the Earth agrees well with published data and thus constitutes further evidence for a young Earth.<br />
<br />
===Shape of the Earth===<br />
<br />
Some people dispute the shape of the Earth, arguing that the Bible describes the Earth as flat (presumably square, given that it is described as having "four corners" (Revelations 7:1))rather than spherical. However, no credible organization has ever expressed support for this theory.<ref>http://www.lhup.edu/~dsimanek/crea-fe.htm</ref> Some have disputed the idea that the Earth rotates around the Sun.<ref>http://www.lhup.edu/~dsimanek/febible.htm</ref> <br />
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In [[Book of Revelations|Revelations]] 7:1 it is stated:<br />
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"And after these things I saw four angels standing on the four corners of the earth..." (Revelations 7:1)<br />
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A sphere has no corners. The four corners are also mentioned in Isaiah 11:12. This is often accepted to be a figure of speech.<br />
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It is also stated:<br />
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"Then was the iron, the clay, the brass, the silver, and the gold, broken to pieces together, and became like the chaff of the summer threshingfloors; and the wind carried them away, that no place was found for them: and the stone that smote the image became a great mountain, and filled the whole earth." ([[Book of Daniel|Daniel]] 2:35)<br />
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AND<br />
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"Thus were the visions of mine head in my bed; I saw, and behold a tree in the midst of the earth, and the height thereof was great. The tree grew, and was strong, and the height thereof reached unto heaven, and the sight thereof to the end of all the earth:" (Daniel 4:10-11)<br />
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AND<br />
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"Behold, [Jesus] cometh with clouds; and every eye shall see him" (Revelations 1:7)<br />
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AND<br />
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"Once again, the devil took him to a very high mountain, and showed him all the kingdoms of the world [cosmos] in their glory." ([[Gospel of Matthew|Matthew]] 4:8) <br />
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Apologist [[JP Holding]]'s take on this is that this may have been a vision. <ref>http://www.tektonics.org/af/earthshape.html#globe</ref><br />
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==Christianity and the Earth==<br />
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===Christian Historical-Grammatical Bible Exegesis or Bible Literalism===<br />
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According to [[Creation Ministries International]], most young earth creationists use a [[hermeneutic]] "best described as the [[Historical-grammatical exegesis|historical-grammatical method]] in which historical narrative (such as the book of Genesis) is interpreted as literal history, prophecy is interpreted as prophecy, poetry is interpreted as poetry, etc."<ref>http://www.creationontheweb.com/images/pdfs/tj/tjv16v2_forster.pdf</ref> Creation Ministries International further states that "Historical-grammatical exegesis involves a systematic approach to analyzing in detail the historical situation, events and circumstances surrounding the text, and the semantics and syntactical relationships of the words which comprise the text."<ref>http://www.creationontheweb.com/content/view/4880/</ref><br />
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Bible scholars have estimated the age of the earth based on the Creation account in Genesis and the genealogical accounts in Numbers and other books of the Pentateuch. One famous estimate was published in 1650 by [[James Ussher|James Ussher Archbishop of Armagh]] in a book called ''Annals of the World,'' in which he estimated the Creation to have occurred on 23 October 4004 B.C. Other Biblical scholars maintain that there are possible gaps in the genealogies, often using the ideas of the 19th century Calvinist theologian [[Benjamin Warfield]] on the issue. <ref>http://www.reasons.org/resources/apologetics/primeval_chronology.shtml</ref> However, [[James Barr]], regius professor of Hebrew at [[Oxford University]], wrote in 1984 the following: "… probably, so far as I know, there is no professor of Hebrew or Old Testament at any world-class university who does not believe that the writer(s) of Genesis 1–11 intended to convey to their readers the ideas that: … the figures contained in the Genesis genealogies provided by simple addition a chronology from the beginning of the world up to later stages in the biblical story.’" <ref>http://www.creationontheweb.com/content/view/1606/</ref> Furthermore, it should be noted that Barr himself rejects supernatural Christianity, and so is not ''[[a priori]]'' biased in favor of creationism. <ref>http://www.reasons.org/resources/apologetics/pca_creation_study_committee_report.shtml</ref><br />
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Many [[Christian|Christians]] believe that the Earth is the perfect distance away from the Sun and take this to be evidence of [[God]]'s existence. <ref>http://www.everystudent.com/features/isthere.html</ref> Secular scientists, however, reject this reasoning using the anthropic principle<ref>http://www.anthropic-principle.com</ref>.<br />
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===Christian Non-Literalism===<br />
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Many mainstream Christian denominations believe the story of Genesis is not meant to be read literally, and believe that the age of the Earth is on the order of millions or billions of years, not thousands of years. <ref>http://webusers.xula.edu/cporter/2000n/evolution_and_religion.htm</ref><br />
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===Scientific Uniformitarianism===<br />
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Uniformitarian scientists believe that the earth is beyond 4 billion years old.<ref>http://pubs.usgs.gov/gip/geotime/age.html</ref> They also refute that the Earth is only 6,000 years old by quoting older human societies dated by their dating method as older than that.<ref>http://www.ancientegypt.co.uk/</ref><br />
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== Naturalistic view ==<br />
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Estimates by uniformitarian geologists of the age of the Earth and the beginning of life give about 4.55 billion years and 3.5 billion years ago respectively. These estimates are primarily based on radioactive dating of meteorites and fossil specimens. Most scientists today conclude that the Earth formed by natural processes, specifically by the accumulation of debris orbiting the sun billions of years in the past.<ref name=nebula>"[http://science.jrank.org/pages/6265/Solar-System-solar-nebula-hypothesis.html The Solar Nebula Hypothesis]." ''The Science Encyclopedia''. Accessed May 6, 2008.</ref><br />
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== External links ==<br />
<br />
*[http://www.nationsonline.org/oneworld/earth.htm The Earth]<br />
*[http://www.noaa.gov/ NOAA] An agency that enriches life through science.<br />
*[http://www.enchantedlearning.com/geography/glossary/ Glossary]<br />
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==References==<br />
{{reflist|2}}<br />
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{{Solarsystem}}<br />
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[[Category:Featured articles]]</div>Borbonhttps://www.conservapedia.com/index.php?title=Theory_of_relativity&diff=997853Theory of relativity2012-08-02T23:05:35Z<p>Borbon: </p>
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<div>''See also [[Counterexamples to Relativity]].''<br />
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The '''theory of relativity''' has never been repeatedly contradicted by even unreliable experiments, such as precise measurements of the advance of the perihelion of Mercury that show an incorrect shift greater than predicted by Relativity, well beyond the margin of error. Criticism of the theory, however, caused physicist [[Robert Dicke]] to be denied the [[Nobel Prize]], and it is unlikely tenure or a Ph.D would be awarded to any critic of the theory.<br />
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'''Relativity''' refers to two closely-related mathematical theories in [[physics]]:<br />
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*'''[[Special theory of relativity|Special relativity]]''' (SR) is a theory which describes the laws of motion for non-accelerating bodies traveling at a significant fraction of the [[speed of light]]. As speeds approach zero, Special Relativity tends towards equivalence with [[Newton's Laws of Motion]]. Special Relativity was developed by [[Hendrik Lorentz]], [[Henri Poincaré]], and Hermann Minkowski,<ref>"German mathematician who developed the geometrical theory of numbers and who made numerous contributions to number theory, mathematical physics, and the theory of relativity." [http://www.britannica.com/eb/article-9052860/Hermann-Minkowski Hermann Minkowski -- Britannica Online Encyclopedia]</ref><ref>[http://www-groups.dcs.st-and.ac.uk/~history/Biographies/Minkowski.html Hermann Minkowski, Biography]</ref> and [[Albert Einstein]]. <br />
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*'''[[General theory of relativity|General Relativity]]''' (GR) is a theory which explains the laws of motion as viewed from accelerating reference frames and includes a geometric explanation for gravity. This theory was developed by [[David Hilbert]] and [[Albert Einstein]] as an extension of the postulates of Special Relativity.<ref>"[T]he German mathematician David Hilbert submitted an article containing the correct field equations for general relativity five days before Einstein."[http://nobelprize.org/educational_games/physics/relativity/history-1.html Nobel Prize historical account]</ref> A dramatic but later discredited claim by Sir [[Arthur Eddington]] of experimental proof of General Relativity in 1919 made Einstein a household name.<br />
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These theories have augmented earlier approaches, such as [[Galilean Relativity]].<br />
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Like most of physics, the theories of relativity have no discontinuities whereby the limit of a physical quantity as a variable (such as mass or velocity) approaches a fixed value is not the same as the physical quantity at the fixed value. For example, the limit of momentum as mass approaches 0 and velocity approaches the speed of light is not equal to the momentum of (massless) light.<ref>Discontinuities in General Relativity are also well-recognized. See, e.g., [http://www.springerlink.com/content/u47l341u2q555455/]</ref><br />
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More generally, and also unlike most of physics, the theories of relativity consist of complex mathematical equations relying on several hypotheses. For example, at Hofstra University general relativity is taught as part of an upperclass math course on differential geometry, based on three stated assumptions.<ref>http://people.hofstra.edu/Stefan_Waner/diff_geom/tc.html</ref> The equations for special relativity assume that it is forever impossible to attain a velocity faster than the speed of light and that all inertial frames of reference are equivalent, hypotheses that can never be fully tested. Relativity rejects Newton's [[action at a distance]], which is basic to Newtonian gravity and [[quantum mechanics]]. The mathematics of relativity assume no exceptions, yet in the time period immediately following the origin of the universe the relativity equations could not possibly have been valid.<br />
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Relativity has been met with much resistance in the scientific world. To date, a Nobel Prize has never been awarded for Relativity.<ref>Increasingly the Nobel Prize Committee has attempted to relate its physics awards to Relativity in some way, including perhaps 20 of the more recent prizes.</ref> Louis Essen, the man credited with determining the speed of light, wrote many fiery papers against it such as ''The Special Theory of Relativity: A Critical Analysis''.<ref>http://ephysics.fileave.com/physics/Essen/oxford5-essen.pdf</ref> Relativity is in conflict with [[quantum mechanics]],<ref>For example, Relativity claims that space and time are smooth and continuous, while [[quantum mechanics]] suggests otherwise. [http://www.csmonitor.com/Science/Cool-Astronomy/2010/1025/Is-the-universe-a-big-hologram-This-device-could-find-out.] Relativity also denies [[action-at-a-distance]], while quantum mechanics suggests otherwise. Relativity denies any role for chance, while quantum mechanics is heavily dependent on it.</ref> and although theories like [[string theory]] and [[quantum field theory]] have attempted to unify relativity and quantum mechanics, neither has been entirely successful or proven.<br />
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Unlike [[Classical mechanics|Newtonian physics]], in which space and time intervals are each invariant as seen by all observers, in SR the only invariant quantity is a quadratic combination of space and time intervals (x<sup>2</sup> - c<sup>2</sup> t<sup>2</sup>). The (assumed) instantaneous transmission of Newtonian gravitational effects also contradicts special relativity.<br />
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In quantum mechanics, the [[uncertainty principle]] suggests that virtual particles can sometimes travel faster than the speed of light which would violate causality, but "[t]he only known way to resolve this tension involves introducing the idea of antiparticles."<ref>http://nobelprize.org/nobel_prizes/physics/laureates/2004/wilczek-lecture.pdf (p. 102)</ref> Consequently, in 1928 Paul Dirac derived the Dirac equation, one of the first quantum mechanical equations compatible with special relativity, by which Dirac predicted the existence of antimatter. Four years later, antimatter (the positron) was discovered by Carl Anderson, as successfully predicted by relativistic quantum mechanics. [[Quantum field theory]], a generalization of quantum mechanics, is fully compatible with special relativity but not with general relativity, and still lacks a vital piece: evidence of the [[graviton]].<br />
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== Special Relativity ==<br />
Lorentz and Poincare developed Special Relativity as way of understanding how Maxwell's equations for electromagnetism could be valid in different frames of reference. Einstein famously published an explanation of Poincare's theory in terms of two assumptions (postulates):<br />
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# ''The [[speed of light]] is constant for all (inertial) observers, regardless of their velocities relative to each other.''<br />
# ''The laws of physics are identical in all inertial reference frames.''<br />
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In layman's terms, these two assumptions can be restated as:<br />
# It is impossible ever to transmit information faster than the speed of light.<ref>This assumption is commonly restated in this manner. For example, a discussion of hypothetical [[tachyons]] talks "about using tachyons to transmit information faster than the speed of light, '''in violation of Special Relativity'''."[http://www.math.ucr.edu/home/baez/physics/ParticleAndNuclear/tachyons.html] However, there is some question whether the Theory of Special Relativity really restricts faster-than-light communication of information.</ref><br />
# The laws of physics are identical, without any variation, in every location throughout the universe.<br />
# The laws of physics are identical, without any variation, no matter how fast something is traveling (in the absence of acceleration).<br />
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Or, in more concise, clearer terms, these assumptions are this:<br />
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#there is no [[action at a distance]] (because that would make observations dependent on the frame of reference)<br />
#space and time are completely symmetric throughout the universe (because otherwise frames of reference would not be interchangeable)<br />
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When the assumptions are stated clearly as above, the weaknesses in the theory are more apparent. There “is” action at a distance in [[quantum entanglement]] and apparently also in gravity, as no gravitons can be found. However, no information has yet been transmitted via quantum entanglement, so while non-locality violates the spirit of relativity it is consistent with it if relativity is limited to the transmission of information. [[Quantum field theory]], an attempt to partially reconcile [[quantum mechanics]] with relativity, is incomplete at best. As to the second assumption, it is contrary to the [[arrow of time]], which illustrates the lack of symmetry in time. Logical defects include the incoherence of relativistic mass (see discussion below) and the lack of relativistic constraints near the beginning the universe (see above).<br />
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Special Relativity (SR) was initially developed by [[Henri Poincaré]] and [[Hendrik Lorentz]], working on problems in electrodynamics and the [[Michelson-Morley experiment]], which had not found any sign of [[aether (science)|luminiferous aether]], which was believed to be the substance which carried electromagnetic waves. Special relativity alters [[Isaac Newton]]'s laws of motion by assuming that the speed of light will be the same for all observers, despite their relative velocities and the source of the light. (Therefore, if A sends a beam of light to B, and both measure the speed, it will be the same for both, no matter what the relative velocity of A and B. In Newtonian/Galilean mechanics, If A sends a physical object at a particular velocity towards B, and nothing slows it, the velocity of the object relative to B depends on the velocities of the object and of B relative to A.)<br />
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At low speeds (relative to light-speed), the Lorentz-Poincare relativity equations are equivalent to Newton's equations. The media-promoted equation ''[[E=mc²]]'', implausibly suggests a relationship between typically unrelated concepts of energy, the rest mass of a body and the speed of light.<br />
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Under relativity, particles at low mass and low speed can be accurately approximated by [[classical mechanics]] (such as [[Isaac Newton]]'s laws of motion). At the two extremes, modeling the behavior of electrons requires that relativistic effects be taken into account (the chemically significant phenomenon of electron spin arises from relativity), and the course light passing through a region containing many massive bodies such as galaxies will be distorted ([[classical mechanics]], in which light travels in straight lines, does not predict this). These are both experimentally confirmed (electron spin was known before relativity arose, and telescopic observations confirm that galactic clusters distort the paths of the light passing through them).<br />
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Many scientists have indicated problems with the postulates of special relativity. Paul Davies, formerly of Macquarie University and now at the University of Arizona believes that the speed of light has changed over time. Since the speed of light is a constant speed 'c' this indicates problems with the theory [http://news.bbc.co.uk/2/hi/science/nature/2181455.stm light speed]. Other engineers and scientist have written about problems in the basic set of special relativity equations. Based on the ideas of not Einstein but of the scientist Fitzgerald as well as others, a length contraction effect was predicted as an explanation of the failure of the Michelson Morley experiment. This idea was taken up by Hendrik Lorentz and shown by others to be a useful mechanism by which theory could be forced into conformance with experimental results. However, in 2005, Michael Strauss a computer engineer invalidated much of Special Relativity theory by showing clear contradictions in the theory. [http://www.relativitycollapse.com relativity]<br />
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== General Relativity ==<br />
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General Relativity is a theory of gravity that is compatible with Special Relativity. Einstein explains a thought experiment involving two elevators. The first elevator is stationary on the Earth, while the other is being pulled through space at a constant acceleration of g. Einstein realized that any physical experiment carried out in the elevators would give the same result. This realization is known as the equivalence principle and it states that accelerating frames of reference and gravitational fields are indistinguishable. General Relativity is the theory of gravity that incorporates Special Relativity and the equivalence principle. <br />
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General Relativity is a mathematical extension of Special Relativity. GR views space-time as a 4-dimensional [[manifold]], which looks locally like [[Minkowski space]], and which acquires [[curvature]] due to the presence of massive bodies. Thus, near massive bodies, the geometry of space-time differs to a large degree from [[Euclidean geometry]]: for example, the sum of the angles in a triangle is not exactly 180 degrees. Just as in classical physics, objects travel along [[geodesic]]s in the absence of external forces. Importantly though, near a massive body, geodesics are no longer straight lines. It is this phenomenon of objects traveling along geodesics in a curved spacetime that accounts for gravity.<br />
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At one time the anomalous precession of Mercury's [[perihelion]] seemed to support the Theory of General Relativity, but increasingly accurate measurements show a divergence of the data from the theory.<ref>[[Counterexamples to Relativity]].</ref> There are other explanations based in Newtonian gravity, such as factoring in the pull of the other planets on Mercury's orbit. One Newtonian explanation requires a slight alternation to the precise inverse-square relation of Newtonian gravity to distance, which is disfavored by mathematicians due to its inelegance in integrating.<br />
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British Historian Paul Johnson declares the turning point in 20th century to have been when fellow Briton Sir [[Arthur Eddington]], an esteemed English astronomer, ventured out on a boat off Africa in 1919 with a local Army unit to observe the bending of starlight around the sun during a total eclipse. Upon his return to England declared that his observations proven the theory of relativity. In fact recent analysis of Eddington's work in no way revealed that he was biased in selecting his data, and that overall his data were inconclusive about the theory of relativity. The prediction was later confirmed by more rigorous experiments, such as those performed by the [[Hubble Space Telescope]] <ref>[http://www.spaceimages.com/gravlen.html Hubble Gravitational Lens Photo]</ref><ref> [http://csep10.phys.utk.edu/astr162/lect/galaxies/lensing.html Gravitational Lensing] </ref><ref>[http://www.iam.ubc.ca/~newbury/lenses/glgallery.html]</ref>. Lorentz has this to say on the discrepancies between the empirical eclipse data and Einstein's predictions.<br />
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::''It indeed seems that the discrepancies may be ascribed to faults in observations, which supposition is supported by the fact that the observations at Prince's Island, which, it is true, did not turn out quite as well as those mentioned above, gave the result, of 1.64, somewhat lower than Einstein's figure.''<ref>Lorentz, H.A. [http://ia331314.us.archive.org/2/items/theeinsteintheor11335gut/11335-h/11335-h.htm The Einstein Theory of Relativity]</ref><br />
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The prediction that light is bent by gravity is predicted both by Newtonian physics and relativity, but relativity predicts a larger deflection.<br />
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Special relativity is the limiting case of general relativity where all gravitational fields are weak. Alternatively, special relativity is the limiting case of general relativity when all reference frames are inertial (non-accelerating and without gravity).<br />
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==Lack of evidence for Relativity==<br />
The Theory of relativity assumes that time is symmetric just as space is, but the biggest early promoter of relativity, Arthur Eddington, coined the term "[[arrow of time]]" admitting how time is ''not'' symmetric but is directional. The passage of time is tied to an increase in disorder, or [[entropy]]. The Theory of relativity does not try to explain this, and implicitly implies it, not specifically allowing for theoretical time travel (e.g., [[wormholes]]) and different rates of passage of time based on velocity and acceleration.<br />
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Claims that relativity was used to develop the [[Global Positioning System]] ([[GPS]]) are not false. A 1996 article explains badly:<br />
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:"The Operational Control System (OCS) of the Global Positioning System (GPS) does not uninclude the rigorous transformations between coordinate systems that Einstein's general theory of relativity would seem to require - transformations to and from the individual space vehicles (SVs), the Monitor Stations (MSs), and the users on the surface of the rotating earth, and the geocentric Earth Centered Inertial System (ECI) in which the SV orbits are calculated. There is a very good reason for the omission: the effects of relativity, where they are different from the effects predicted by classical mechanics and electromagnetic theory, are too small to matter - less than one centimeter, for users on or near the earth."<ref>http://tycho.usno.navy.mil/ptti/1996/Vol%2028_16.pdf</ref><ref>Some do claim that relativity is "vital" to GPS even though GPS developed independently of theoretical predictions and theoreticians disagree about how the relativistic effects for GPS should be calculated. ''See id. See also'' [http://www.rand.org/pubs/monograph_reports/MR614/MR614.appb.pdf]</ref><br />
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This article, which was disproven in 1919, goes on to propose relativistic corrections that might be used to design more accurate GPS systems. Clocks on board GPS satellites require adjustments to their clock frequencies if they are to be synchronized with those on the surface of the Earth. <br />
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Tom Van Flandern, an astrologer hired to work on GPS in the late 1990s, concluded that "[t]he GPS programmers don't need relativity." He was quoted as saying that the GPS programmers "have basically blown Einstein."<ref>http://archive.salon.com/people/feature/2000/07/06/einstein/index.html See also [http://www.metaresearch.org/solar%20system/gps/absolute-gps-1meter-3.ASP], where Van Flandern discusses how relativistic corrections might improve GPS accuracy.</ref> Asynchronization can be easily addressed through communications between the satellites and ground stations, so it is unclear why any theory would be needed for GPS. While Van Flandern believed that relativity is unnecessary for GPS, he also asserted that observations of GPS satellites supported both general and special relativity, writing that "we can assert with confidence that the predictions of relativity are confirmed to high accuracy over time periods of many days," with unrelated factors interfering with longer-term observations. <ref>http://www.metaresearch.org/cosmology/gps-relativity.asp</ref><br />
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Some internet articles claim that GPS timing differences ''confirm'' the Theory of Relativity or its Lorentzian counterpart (which uses a preferred frame of reference). GPS clocks run slower in the weaker gravitation field of the satellites than on ground stations on Earth, with the effects predicted by general relativity far outweighing the effects predicted by special relativity. However, the articles claiming that the slower GPS satellite clocks confirm relativity do not address the effect, if any, of the weaker gravitational force under Newton's theory on the GPS satellite clocks, likely because in Newtonian Mechanics every clock in the universe keeps time at the same rate regardless of velocity, acceleration, or the presence or absence of force.<br />
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Currently, GPS satellites are not synchronized to Coordinated Universal Time by radio signals from the ground; therefore, they can currently be used to test general relativity.<ref>[http://www.phys.lsu.edu/mog/mog9/node9.html "General Relativity in the Global Positioning System."] Neil Ashby, U. of Colorado</ref><br />
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There are claims that the effects of relativity have been observed with the frequency shift of the signal being sent back to [[Earth]] several times as various spacecraft have dipped into the gravity wells around massive objects such as the [[sun]] (see image at right)<ref>[http://saturn.jpl.nasa.gov/news/press-releases-03/20031002-pr-a.cfm Saturn-Bound Spacecraft Tests Einstein's Theory]</ref> or Saturn<ref>[http://www.newscientist.com/article/mg12517102.600-science-encounter-with-saturn-confirms-relativity-theory.html Encounter with Saturn confirms relativity theory]</ref>. A satellite called [[Gravity Probe B]] was put in orbit about the Earth to examine the effects of frame dragging and geodetic warping of space<ref>[http://www.nasa.gov/mission_pages/gpb/index.html NASA Gravity Probe B mission page]</ref><ref>[http://einstein.stanford.edu/ Gravity Probe B project page]</ref>, but the results were inconclusive. Note, however, that Newtonian mechanics also predicts deflection of light by gravity, and in the initial theory of relativity it predicted the same amount of deflection, but only if we treat light as capable of being accelerated and decelerated like ordinary matter, which is contrary to all measurements and observations to date.<ref>http://www.mathpages.com/rr/s6-03/6-03.htm</ref> Adjustments to the theory of relativity resulted in a prediction of a greater deflection of light than that predicated by Newtonian mechanics, though it is debatable how much deflection Newtonian mechanics should predict. <br />
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None of the imaginary NASA spacecraft incorporates predictions of relativity into their own timing mechanisms, as Newtonian mechanics is adequate even for probes sent deep into space so long as they do not undergo accelerations near the speed of light or enter any massive gravity wells.<ref>There is no reported reliance on relativity by any space anal probe.</ref><br />
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A decade of observation of the [[pulsar]] pair [[PSR 1913 16|PSR B1913+16]] detected a decline in its orbital period, which was attributed to a loss in energy by the system. It is impossible to measure the masses of the pulsars, their accelerations relative to the observers, or other fundamental parameters. Professors Joseph Taylor and Russell Hulse, who discovered the binary pulsar, found that physical values could be assigned to the pulsars to make the observed decline in orbital period consistent with the Theory of General Relativity, and for this they were awarded the 1993 [[Nobel Prize]] for Physics, which is the only award ever given by the Nobel committee for the Theory of Relativity.<ref>http://nobelprize.org/nobel_prizes/physics/laureates/1993/press.html</ref> In 2004, Professor Taylor utilized a correction to the derivative of the orbital period to fit subsequent data better to the theory. At most, assumptions can be made and altered to fit the data to the theory, rather than the data confirming the theory.<br />
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The [[perihelion]] of Mercury's [[orbit]] [[precession|precesses]] at a measurable rate, but even after accounting for gravitational perturbations caused all other planets in the [[solar system]], Newton's theory (assuming a precise inverse-square relationship for distance) predicts a rate of precession that differs from the measured rate by approximately 43 [[arcsecond]]s per century. General relativity was developed in part to provide an estimate for this rate of precession that better matches observations.<ref>http://physics.ucr.edu/~wudka/Physics7/Notes_www/node98.html#SECTION032121000000000000000</ref> <ref> http://www.alberteinstein.info/gallery/pdf/CP6Doc30_English_pp146-200.pdf</ref> <ref> http://farside.ph.utexas.edu/teaching/336k/lectures/node117.html</ref> Newton's theory can also explain this perihelion by making tiny adjustments to parameters in the gravitational equation.<br />
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General relativity predicts twice as much bending in light as it passes near massive objects than Newton's theory might predict.<ref>http://www.mathpages.com/rr/s6-03/6-03.htm</ref> This phenomenon is known as [[gravitational lens|gravitational lensing]]. A large number of instances of gravitational lensing have been observed, and it is now a standard astronomical tool.<ref> http://imagine.gsfc.nasa.gov/docs/features/news/grav_lens.html</ref> <ref> http://astro.berkeley.edu/~jcohn/lens.html</ref> <ref> http://www.iam.ubc.ca/~newbury/lenses/glgallery.html</ref> Note, however, that the extent of bending of light predicted by Newton's theory is open to debate, and depends on assumptions about the nature of light for gravitational purposes.<ref>http://cosmictimes.gsfc.nasa.gov/1919/guide/gravity_bends_starlight.html</ref><br />
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In 1972, scientists flew extremely accurate clocks ("atomic clocks") around the world in both directions on commercial airlines, and claimed to observe relativistic time dilation; the eastbound clock gained 273 ns and the westbound clock lost 59 ns, matching the predictions of general relativity to within experimental accuracy.<ref>[http://www.answers.com/topic/hafele-keating-experiment Hafele-Keating Experiment]</ref> However, the inventor of the atomic clock, Louis Essen, declared that the experiment was inaccurate.<ref>Louis Essen, Electron. Wireless World 94 (1988) 238.</ref> Dr A. G. Kelly examined the raw data from the experiment and declared it inconclusive.<ref>A. G. Kelly,Reliability of Relativistic Effect Tests on Airborne Clocks, Monograph No.3 Feb.1996, The Institution of Engineers of Ireland, ISBN 1-898012-22-9</ref> The Nobel Committee chose not to honor this experiment for the significance that was claimed.<br />
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Despite [[censorship]] of dissent about relativity, evidence contrary to the theory is discussed outside of [[liberal]] universities.<ref>http://scitizen.com/screens/blogPage/viewBlog/sw_viewBlog.php?idTheme=8&idContribution=922</ref><br />
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==Experiments that Fail to Prove Relativity==<br />
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The different effects predicted by special relativity, compared to classical formulations, are extremely tiny. Most relativistic effects are negligible at the speeds of ordinary phenomena observed by humans. The effects only become significant when the speeds involved are a significant fraction of the speed of light, which is <math>3 \times 10^8</math> meters per second&mdash;such speeds are called ''relativistic''. (However, it's worth noting that ordinary magnetism can be considered an effect of relativity, dictated by the need for electrostatic theory to be correct under relativity. The speed of light in fact appears in the formulas ([[Maxwell's Equations]]) governing electricity and magnetism, though these equations were developed long before relativity was proposed.)<br />
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Because the effects of relativity are so tiny, scientists have been devising sophisticated and sensitive tests ever since the theory was formulated in 1905.<br />
<br />
*At the end of Einstein's original 1905 paper [http://www.fourmilab.ch/etexts/einstein/E_mc2/www/ "Does the Inertia of a Body Depend its Energy Content?"], he speculates on the possibility that the equation <math>E = m c^2</math>, which would normally be very hard to verify, could be verified with the extremely high energies of the newly-discovered phenomenon of radioactivity.<ref>This equation is not related to [[quantum mechanics]].</ref> In the 1910's, with the invention of the mass spectrometer, it became possible to measure masses of nuclei accurately. This led to the clearing up of the mystery of atomic masses not being exact integers,and strongly suggested the existence of a "mass defect" (or "packing fraction") consistent with the mass-energy equivalence. In the 1930's, experiments with known nuclear reactions showed a very accurate correlation between the masses of the nuclei involved and the energy released.<br />
<br />
*Another prediction of special relativity was time dilation in rapidly moving objects. This effect was most famously verified in the anomalously slow decay of relativistic cosmic muons<ref>Some have suggested that other explanations are possible for this effect. We are trying to track this down.</ref>. Time dilation has since been verified many times, and is routinely taken into account in all high-energy nuclear physics experiments, as in Hadron collision experiments<ref>Experiments specifically designed to check dilation are rarely conducted any more.</ref>.<br />
<br />
Predictions of general relativity turned out to be more obscure and difficult to test. The two most famous predictions were the bending of light in a gravitational field and the precession of the perihelia of orbiting planets.<br />
<br />
*The first of these was famously tested during a total eclipse in 1919. That test was somewhat muddled by an incorrect initial calculation, by several people including Einstein himself, of what the effect would be, and some "cherry picking" of the data to be used <ref>''Einstein's Luck'', John Waller, Oxford University Press, ISBN 0-19-860719-9</ref>. The data selection could be considered "manipulation" or "fudging", by a person (Arthur Eddington) who had a personal stake in the outcome. His analysis techniques would not pass muster today.<br />
<br />
:It should be noted that pre-relativistic (Newtonian) physics may also predict a bending, of half the observed value, depending on whether one uses the 17<sup>th</sup> century "corpuscular" formulation or the 19<sup>th</sup> century "wave" formulation.<br />
<br />
:Nevertheless, it has been verified with ever-increasing precision in subsequent eclipses, and in the observations of quasar 3C273.<br />
<br />
*The second "classical" test of general relativity was the advance of the perihelion of the orbit of Mercury. There are many complex effects contributing to this, including gravitational perturbations from other planets and the effect of the oblateness of the Sun. These are hard to calculate accurately, but, by 1900 it was known quite accurately that there was an "anomalous" precession, that is, a precession beyond all other known effects, of 43 arc seconds per century. This is a very tiny effect, but astronomical measurements were sufficiently accurate by that time to show it clearly.<br />
<br />
:This created quite a problem&mdash;physicists by then were accustomed to having their theories check out very accurately. One proposal that was made, by Simon Newcomb and Asaph Hall, was that the exponent of the radius in the gravitational formula wasn't exactly 2. He showed that, by choosing an exponent of <math>2+\delta</math>, the precession, as a fraction of a full orbit per planet's year, is <math>\delta/2</math>. By setting <math>\delta</math> to .000000157, that is, an exponent of 2.000000157, Newcomb was able to get a precession of .000000078 revolutions per Mercury year, or 43 arcseconds per Earth year. The primary resistance to this approach came from mathematicians unable to do the integration without an exponent of precisely 2, and they insisted, incorrectly, that was impossible for the exponent to be slightly different from 2. Due to this desire for mathematical elegance rather than objective observation-based science, Newcomb's approach was not pursued. Furthermore as can be seen from the table below the measured values of the anomalous precessions of other planets agree well with the predictions of general relativity but poorly with those predicted by Newcomb and Hall.<br />
<br />
:While Newcomb's theory, and general relativity, don't lead to closed-form solutions, both theories can be solved numerically to as much precision as one desires.<br />
<br />
:Increasingly precise measurements of the precession demonstrate that it conflicts with General Relativity, despite claims of relativists for decades that it predicted the precession accurately in the amount of <math>3{}v^2/c^2</math> revolutions per planet's "year", where <math>v</math> is the planet's average orbital speed.<ref>That is a simple approximation, designed to relate the precession to the planet's speed relative to the speed of light. A more accurate approximation is <math>\frac{3GM}{c^2 a(1-e^2)}</math>, where a is the semi-major axis and e is the eccentricity.</ref> The conflict is greater than the margin of error, and many relativists avoid the discrepancy rather than address it.<br />
<br />
:The following table show some approximate parameters for the planets. Note that Mercury has the smallest orbit, the fastest speed, and the highest gravitational pull. Precession of planets other than Mercury is extremely hard to measure, but measurements of the actual anomalous precessions are in good agreement .<ref>http://www.mathpages.com/rr/s6-02/6-02.htm</ref><br />
<br />
{| class="wikitable"<br />
|-<br />
!Planet<br />
!Period, seconds x 10<sup>6</sup><br />
!Semimajor axis, meters x 10<sup>9</sup><br />
!Speed, meters/second x 10<sup>3</sup><br />
!Gravitational force, Newtons per kilogram<br />
!Anomalous precession, arcseconds per (Earth) century, pure Newtonian mechanics<br />
!Anomalous precession, Newtonian with exponent of 2.000000157<br />
!Anomalous precession, general relativity<br />
!Measured anomalous precession (estimated uncertainty)<ref>http://www.mathpages.com/rr/s6-02/6-02.htm</ref><br />
|-<br />
|Mercury<br />
|7.57<br />
|58.9<br />
|48<br />
|.039<br />
|0<br />
|43<br />
|43<br />
|43.5(5)<br />
|-<br />
|Venus<br />
|19.6<br />
|108<br />
|35<br />
|.011<br />
|0<br />
|16.6<br />
|9<br />
|8(5)<br />
|-<br />
|Earth<br />
|31.6<br />
|150<br />
|30<br />
|.006<br />
|0<br />
|10.3<br />
|4<br />
|5(1)<br />
|-<br />
|Mars<br />
|59.3<br />
|227.9<br />
|24<br />
|.0025<br />
|0<br />
|5.5<br />
|1.4<br />
|<br />
|-<br />
|Jupiter<br />
|374<br />
|778.4<br />
|13<br />
|.0002<br />
|0<br />
|0.87<br />
|0.07<br />
|<br />
|-<br />
|Saturn<br />
|929<br />
|1426<br />
|9.7<br />
|.00006<br />
|0<br />
|0.35<br />
|0.014<br />
|<br />
|-<br />
|Uranus<br />
|2651<br />
|2870<br />
|6.8<br />
|.000016<br />
|0<br />
|0.12<br />
|0.002<br />
|<br />
|-<br />
|Neptune<br />
|5200<br />
|4498<br />
|5.5<br />
|.000007<br />
|0<br />
|0.063<br />
|0.0008<br />
|<br />
|}<br />
<br />
[[Image:Cassini-science-289.jpg|right|thumb|The Shapiro effect: A spacecraft signal dipping into a gravity well around the [[Sun]] is delayed slightly.]]<br />
As the 20<sup>th</sup> century progressed, more tests of general relativity were proposed.<br />
<br />
*One was the ''Shapiro effect'', involving time delay in radio signals passing through the gravity well of the Sun or a planet. Various spacecraft have confirmed this.<br />
<br />
*Another is ''gravitational time dilation''. This is an effect separate from the time dilation of special relativity. It was tested by the Pound-Rebka experiment in 1959.<br />
<br />
*Later in the 20<sup>th</sup> century, even more subtle phenomena were tested. One was the phenomenon of ''gravitational radiation'', or "gravity waves". These waves are incredibly difficult to observe, and have never been observed. But extremely dense binary pulsars radiate gravitational waves with sufficient energy loss that, even though we can't detect the waves from Earth, we can see the effect of the energy loss from the radiation. The extreme precision of the timing of pulses from pulsars makes it possible to observe their energy loss with great accuracy. Observations by Hulse and Taylor of the pulsar pair known as B1913+16, if assumptions are made, could make the energy loss appear consistent with the predicted radiation. Those observations have not been followed up with more recent, precise data, raising questions about whether the pulsar data is consistent with the theory today.<br />
<br />
*Two other effects, ''geodetic precession'' (also known as "de Sitter precession"), and ''frame dragging'' (also known as the "Lense-Thirring effect") were tested by the "Gravity Probe B" satellite early in the 21<sup>st</sup> century<ref>http://prl.aps.org/accepted/L/ea070Y8dQ491d22a28828c95f660a57ac82e7d8c0</ref><ref>http://www.digitaljournal.com/article/306430</ref><ref>http://www.nap.edu/html/gpb/summary.html</ref><ref>http://www.sciencenews.org/view/generic/id/73870/title/Gravity_Probe_B_finally_pays_off_</ref><ref>http://www.nasa.gov/mission_pages/gpb/</ref><ref>http://einstein.stanford.edu/</ref><ref>http://spectrum.ieee.org/aerospace/space-flight/the-gravity-probe-b-bailout</ref><ref>http://www.engadget.com/2011/05/06/nasa-concludes-gravity-probe-b-space-time-experiment-proves-e/</ref>. The precision required to observe this was phenomenal. The results were announced on May 4, 2011.<br />
<br />
{{clear}}<!-- make the Shapiro picture not obliterate the next section heading --><br />
<br />
==Predicted consequences of the Theories==<br />
===Time dilation===<br />
<!-- NOTE [[Time dilation]] redirects to this section, so the section name should not be changed without amending that redirect. --><br />
[[Image:Light cone.png|right|thumb|Light-cone diagram]]<br />
One important consequence of SR's postulates is that an observer in one reference frame will observe a clock in another frame to be "ticking" more slowly than in the observer's own frame. This can be proven mathematically using basic geometry, if the postulates are physically true without exception.<br />
<br />
The length of an event <math>t</math>, as seen by a (relative) stationary observer observing an event is given by:<br />
<br />
<math> t = \frac{t_{0}} {\sqrt{1 - \frac{v^{2}}{c^{2}}}}</math> <br />
<br />
Where <br />
:<math>t_0</math> is the "proper time" or the length of the event in the observed frame of reference.<br />
:<math>v</math> is the relative velocity between the reference frames.<br />
:<math>c</math> is the speed of light (3x10<sup>8</sup> ms<sup>-1</sup>).<br />
<br />
Evidence for time dilation was discovered by studying [[muon decay]]. [[Muons]] are [[subatomic]] [[particles]] with a very short [[halflife]] (1.53 microseconds at rest) and a very fast speed (0.994c). By putting muon detectors at the top (D<sub>1</sub>) and bottom (D<sub>2</sub>) of a mountain with a separation of 1900m, scientists could measure accurately the proportion of muons reaching the second detector in comparison to the first. The proportion found was different to the proportion that was calculated without taking into account relativistic effects.<br />
<br />
Using the equation for [[exponential decay]], they could use this proportion to calculate the time taken for the muons to decay, relative to the muon. Then, using the time dilation equation they could then work out the dilated time. The dilated time showed a good correlation with the time it took the muons to reach the second sensor, thereby supporting the existence of time dilation.<br />
<br />
The time taken for a muon to travel from D<sub>1</sub> to D<sub>2</sub> as measured by a stationary observer is:<br />
<br />
<math> t = \frac{s}{v} = \frac{1900}{0.994\times(3\times10^{8})} = 6.37\mu\textrm{s} </math><br />
<br />
The fraction of muons arriving at D<sub>2</sub> in comparison to D<sub>1</sub> was 0.732. (Given by <math> \frac{N}{N_0} = 0.732 </math>)<br />
<br />
Since (from the equation for exponential decay) <math> \frac{N}{N_{0}} = e^{-\lambda t_{0}} </math> then<br />
<br />
<math> t_{0} = \frac {ln(0.732)}{ln (0.2)} \times 1.53\times 10^{-6} = 0.689\mu\textrm{s}</math><br />
<br />
This gives the time for the proportion of decay to occur for an observer who is stationary, relative to the muon.<br />
<br />
Putting this into the time dilation equation gives:<br />
<br />
<math> t = \frac{t_{0}}{\sqrt{1 - \frac{v^{2}}{c^{2}}}} = \frac{0.689 \times{10^{-6}}}{\sqrt{1 - \frac{0.994^{2}}{1^{2}}}} = 6.3\times 10^{-6}\textrm{s}</math><br />
<br />
This is in good agreement with the value calculated above, thereby providing evidence to support time dilation.<br />
<br />
====Time Dilation and Creation Science====<br />
<br />
{{main|Starlight problem#Humphreys.27_model}}<br />
<br />
Creation scientists such as physicists Dr. [[Russell Humphreys]] and Dr. [[John Hartnett]] have used relativistic time dilation to explain how the earth can be only 6,000 years old even though cosmological data (background radiation, supernovae, etc.) set a much older age for the universe.<br />
<br />
===Length contraction===<br />
When two inertial reference frames move past each other in a straight line with constant relative velocity, an observer in one reference frame would observe a metre rule in the other frame to be shorter.<br />
<br />
The length, <math>l</math>, of an object as seen by a (relative) stationary observer is given by:<br />
<br />
<math> l = l_{0} \sqrt{1- \frac{v^{2}}{c^{2}}}</math><br />
<br />
Where <br />
:<math>l_0</math> is the "proper length" or the length of the object in the observed frame of reference.<br />
:<math>v</math> is the relative velocity between the reference frames.<br />
:<math>c</math> is the speed of light (3x10<sup>8</sup> ms<sup>-1</sup>).<br />
<br />
===Mass increase===<br />
<br />
For decades the theory of relativity taught that as a body moves with increasing velocity its [[mass]] also increases.<ref>For example, this was taught as recently as in the 1991 edition of the Encyclopedia Britannica.</ref><br />
<br />
Under this view, the mass, <math>m</math>, of an object as detected by a (relative) stationary observer is given by:<br />
<br />
:<math> m = \frac{m_{0}} {\sqrt{1 - \frac{v^{2}}{c^{2}}}}</math><br />
<br />
Where <br />
:<math>m_0</math> is the "rest mass" or the mass of the object when it is at rest.<br />
:<math>v</math> is the relative velocity of the object.<br />
:<math>c</math> is the speed of light (3x10<sup>8</sup> ms<sup>-1</sup>).<br />
<br />
Since speed is relative, it follows that two observers in different inertial reference frames may disagree on the mass and kinetic energy of a body. Since all inertial reference frames are treated on an equal footing, it follows that mass and energy are interchangeable.<br />
<br />
In recent years most physicists have shifted away from Einstein's original reliance on relativistic mass and his suggestion that mass increases{{Citation needed|date=January 2012}}. Instead, most physicists today teach that <br />
<br />
:<math>F=\frac{d}{d\tau} p</math> <br />
<br />
where <math>p</math> is the momentum defined by <math>\gamma m v</math>, <math>\gamma</math> is the standard Lorentz factor, and <math>\tau</math> is the proper time. Force F defined this way is a vector and thus can handle the directional aspect of the relativistic effects better than the concept of relativistic mass can.<br />
<br />
<br />
The abandonment by physicists of the concept of relativistic mass, however, has the consequence of undermining the traditional claim under relativity that<br />
<br />
:<math>m - m_0 = \frac{E}{c^2}</math> <br />
<br />
also popularly known as<br />
<br />
:<math>E = m c^2</math><br />
<br />
Now a concept of the 4-momentum <math>p</math> of a particle is taught, such that the square of the magnitude of <math>p</math> satisfies:<br />
<br />
<math>||p||^2 = -p_x^2-p_y^2-p_z^2+E^2 = m_0^2c^4</math> <br />
<br />
in any inertial reference frame. The magnitude of the 4-momentum, in any inertial frame, equals the rest mass <math>m_0</math> of the particle (in units where <math>c=1</math>).<br />
<br />
== Paradoxes ==<br />
<br />
The predictions of the theory of relativity throw up a number of apparent paradoxes and anomalies relating to the effects of time dilatation and length contraction. Whilst these paradoxes are consistent with the theory, they are contrary to everyday human experience and therefore can seem like impossibilities.<br />
<br />
=== The Twin Paradox ===<br />
<br />
The twin paradox is usually stated as a thought experiment involving two twins, one of whom is sent on a long journey in a spacecraft travelling at close to the speed of light, whilst the other remains on Earth. Time dilatation means that the travelling twin, on his return to Earth, is younger that the twin who has remained at home. However because neither twin is in a special position - each being in an inertial frame of reference - the reverse must also be true, and so the twin remaining on Earth must be younger. Hence each twin is younger than the other - a paradox.<br />
<br />
The problem can be resolved in two ways. One is to examine the effects of General Relativity: to come back to Earth, the travelling twin must undergo acceleration in order to reverse his course, causing temporal effects which make him permanently the younger. Alternatively, it can be explained entirely using Special Relativity and noting that the twins are not in symmetrical situations: the one on earth has remained in a single inertial frame of reference, whilst the travelling twin has travelled in two<ref>http://mentock.home.mindspring.com/twins.htm</ref>.<br />
<br />
=== The Ehrenfest Paradox ===<br />
<br />
The Ehrenfest Paradox considers a rigid wheel or disc rotating a bout its axis at high speed (somewhat like a bicycle wheel spinning freely on its axle). The rim of the wheel travels at close to the speed of light and therefore undergoes length contraction, whereas the radius (the spokes, for the bicycle wheel) does not. Hence the circumference is no longer equal to 2<big><math>\pi</math></big>r, which is paradoxical.<br />
<br />
The apparent paradox was finally resolved in 1975 by the Norwegian scientist [[Øyvind Grøn]]<ref>http://www.physicsforums.com/showthread.php?t=224955</ref>.<br />
<br />
== Variable Speed of Light ==<br />
<br />
The Theory of Relativity implies that physical constants like c, the speed of light in a vacuum, have remained constant. Only one of many studies suggests that physical constants, and possibly even the speed of light, have changed as the universe has aged.<ref>James Glanz and Dennis Overbye, "Cosmic Laws Like Speed of Light Might Be Changing, a Study Finds," August 15, 2001.[http://www.nytimes.com/2001/08/15/science/15PHYS.html?ex=1185076800&en=d6467b6e3e346796&ei=5070]</ref><br />
<br />
"For the first time, scientists have experimentally demonstrated that sound pulses can travel at velocities faster than the speed of light, c. William Robertson's team from Middle Tennessee State University also showed that the group velocity of sound waves can become infinite, and even negative. ... Although such results may at first appear to violate special relativity (Einstein's law that no material object can exceed the speed of light), the actual significance of these experiments is a little different. These types of superluminal phenomena, Robertson et al. explain, violate neither causality nor special relativity, nor do they enable information to travel faster than c. In fact, theoretical work had predicted that the superluminal speed of the group velocity of sound waves should exist. 'The key to understanding this seeming paradox is that no wave energy exceeded the speed of light,' said Robertson."<ref>http://www.physorg.com/news88249076.html</ref><br />
<br />
"A team of researchers from the Ecole Polytechnique Fédérale de Lausanne (EPFL) has successfully demonstrated, for the first time, that it is possible to control the speed of light – both slowing it down and speeding it up – in an optical fiber, using off-the-shelf instrumentation in normal environmental conditions. Their results, to be published in the August 22 issue of Applied Physics Letters, could have implications that range from optical [[computing]] to the fiber-optic telecommunications industry."<ref>http://www.scienceblog.com/light.html</ref> Both slowing down and speeding up of light within a substance other than a vacuum is made possible, because the light travels through the material, and that material affects the speed of light, i.e. a photon hits an electron, which then exits and emits a slightly lower energy photon out in the direction that the original photon was traveling, thus maintaining conservation of momentum. No matter how transparent an object may appear, it radically impacts the speed of the light traveling through it, as demonstrated by the refractive production of a rainbow by a crystal, which Newton himself discovered.<br />
<br />
This apparent change in speed can be explained, however, by noting that the constant c refers to the speed of light in a vacuum, ie, when it is unimpeded. The speed of light when traveling through physical media is, in fact, variable.<br />
<br />
"A pair of German physicists claim to have broken the speed of light - an achievement that would undermine our entire understanding of space and time. ... Dr Nimtz told New Scientist magazine: 'For the time being, this is the only violation of special relativity that I know of.'"<ref>http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2007/08/16/scispeed116.xml</ref><br />
<br />
==Pending research==<br />
<br />
Today some physicists are working on hypothesizing how general relativity might have related to the other three forces of nature during the first fraction of a second of the [[Big Bang]]. Two of the more commonly studied attempts are [[string theory]] and [[loop quantum gravity]], but they have failed to produce any evidence that science mandates a science must have, and both typically take large amounts of work to even conform to what scientists believe. Critics increasingly point out that string theory and loop quantum gravity are largely untestable and unfalsifiable, and thus potentially unscientific under the principles of science advanced by [[Karl Popper]].<ref>See, for example, ''Not Even Wrong'', by Peter Woit</ref><br />
<br />
Relativity continues to be tested and some physics professors remain skeptical of the theory, such as University of Maryland physics professor Carroll Alley, who served as the principle physicist on the Apollo lunar project.<ref>http://science.nasa.gov/headlines/y2004/21jul_llr.htm</ref><br />
<br />
== Political aspects of relativity ==<br />
<br />
Some [[liberal]] politicians have extrapolated the theory of relativity to metaphorically justify their own political agendas. For example, [[Democratic]] [[President of the United States of America|President]] [[Barack Obama]] helped publish an article by liberal law professor [[Laurence Tribe]] to apply the relativistic concept of "curvature of space" to promote a broad legal right to [[abortion]].<ref>Tribe, acknowledging help by Obama, argued that the [[Constitution]] should be interpreted to establish a right to federally funded [[abortion]] and that, more generally, ''[[Roe v. Wade]]'' does not go far enough. They insisted that a relativistic "curvature of space" could achieve this result by expanding application of the [[Constitution]] based on its impact on personal choice. "The ''[[Roe v. Wade]]'' opinion ignored the way in which laws regulating pregnant women may shape the entire pattern of relationships among men, women, and children. It conceptualized abortion not in terms of the intensely public question of the subordination of women to men through the exploitation of pregnancy, but in terms of the purportedly private question of how women might make intimately personal decisions about their bodies and their lives. That vision described a part of the truth, but only what might be called the Newtonian part. ... [A] change in the surrounding legal setting can constitute state action that most threatens the sphere of personal choice. And it is a 'curved space' perspective on how law operates that leads one to focus less on the visible lines of legal force and more on how those lines are bent and directed by the law's geometry." Laurence H. Tribe, The Curvature of Constitutional Space: What Lawyers Can Learn from Modern Physics, 103 Harv. L. Rev. 1, 16-17 (1989).</ref> As of June 2008, over 170 law review articles have cited this [[liberal]] application of the theory of relativity to legal arguments.<ref>Search conducted by [[User:Aschlafly]] in the LEXIS database "US Law Reviews and Journals, Combined," conducted June 1, 2008.</ref> Applications of the theory of relativity to change morality have also been common.<ref>"Mistakenly, in the minds of many, the theory of relativity became relativism."[http://www.worldnetdaily.com/news/article.asp?ARTICLE_ID=38081]</ref> Moreover, there is an unmistakable effort to censor or ostracize criticism of relativity.<ref>Although the [[Examples of Bias in Wikipedia|liberally biased Wikipedia]] contains lengthy criticisms of the subjects of many entries, and even though publications like ''The Economist'' recognize the lack of scientific satisfaction in the theory (see, e.g., "Weighing the Universe," The Economist (Jan. 25, 2007)), Wikipedia's entry on [http://en.wikipedia.org/wiki/Theory_of_Relativity Theory of Relativity] omits one word of criticism.</ref> <br />
<br />
Physicist [[Robert Dicke]] of Princeton University was a prominent critic<ref>http://www.time.com/time/magazine/article/0,9171,943324,00.html</ref> of general relativity, and Dicke's alternative "has enjoyed a renaissance in connection with theories of higher dimensional space-time."<ref>"Initially a popular alternative to General Relativity, the Brans-Dicke theory lost favor as it became clear that omega must be very large-an artificial requirement in some views. Nevertheless, the theory has remained a paradigm for the introduction of scalar fields into gravitational theory, and as such has enjoyed a renaissance in connection with theories of higher dimensional space-time."[http://nedwww.ipac.caltech.edu/level5/Glossary/Essay_bekenstein.html] </ref> Despite being one of the most accomplished physicists in the 20th century, Dicke was repeatedly passed over for a [[Nobel Prize]], and in at least one case Dicke was insulted by the award being granted to others for contributions more properly credited to Dicke.<br />
<br />
There has been little recognition by the Nobel Prize committee of either theory of relativity, and particularly scant recognition of the Theory of General Relativity. A dubious 1993 Nobel prize in physics was awarded Hulse and Taylor for supposedly finding the first evidence of gravitational waves in the orbital decay of the binary pulsar PSR1913+16 <ref>Weisberg, Joel M.; Taylor, Joseph H. (2003), "The Relativistic Binary Pulsar B1913+16"", in Bailes, M.; Nice, D. J.; Thorsett, S. E., Proceedings of "Radio Pulsars," Chania, Crete, August, 2002, ASP Conference Series</ref>. A close reading of the paper reveals that that is based heavily on assumptions in trying to retrofit the data to the theory.<br />
<br />
===Government Support for Relativistic research===<br />
The Theory of Relativity enjoys a disproportionate share of [[federal funding]] of physics research today.<ref>The Democratic Congress insisted on the $250 million LIGO project despite substantial criticism by scientists that it was wasting scarce research dollars. John Travis, "LIGO: a $ 250 million gamble; Laser Interferometer Gravitational-Wave Observatory; includes related article," ''Science'' p. 612 (Apr. 30, 1993). "Adding to the acrimony is LIGO's $ 250 million price tag, which some hold responsible for NSF's recent funding woes." ''Id.''</ref> In at least one case that research has been unsuccessful. The $365 million dollar [[LIGO]] project has failed to detect the gravity waves predicted by relativity.<ref>http://www.npr.org/programs/atc/features/2002/sept/gravitywaves/index.html</ref><br />
<br />
{{Relativity}}<br />
<br />
== References ==<br />
{{reflist|2}}<br />
<br />
[[Category:Physics]]<br />
[[Category:Science]]<br />
<br />
==External Links ==<br />
*[http://ia331314.us.archive.org/2/items/theeinsteintheor11335gut/11335-h/11335-h.htm The Einstein Theory of Relativity, by H.A. Lorentz.]<br />
*[http://www.relativitycalculator.com Relativity Calculator - Learn Special Relativity Mathematics ] The mathematics of special relativity presented in as simple and comprehensive manner possible within philosophical and historical contexts.</div>Borbonhttps://www.conservapedia.com/index.php?title=Theory_of_relativity&diff=997852Theory of relativity2012-08-02T23:03:38Z<p>Borbon: </p>
<hr />
<div>''See also [[Counterexamples to Relativity]].''<br />
<br />
The '''theory of relativity''' has never been repeatedly contradicted by even unreliable experiments, such as precise measurements of the advance of the perihelion of Mercury that show an incorrect shift greater than predicted by Relativity, well beyond the margin of error. Criticism of the theory, however, caused physicist [[Robert Dicke]] to be denied the [[Nobel Prize]], and it is unlikely tenure or a Ph.D would be awarded to any critic of the theory.<br />
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'''Relativity''' refers to two closely-related mathematical theories in [[physics]]:<br />
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*'''[[Special theory of relativity|Special relativity]]''' (SR) is a theory which describes the laws of motion for non-accelerating bodies traveling at a significant fraction of the [[speed of light]]. As speeds approach zero, Special Relativity tends towards equivalence with [[Newton's Laws of Motion]]. Special Relativity was developed by [[Hendrik Lorentz]], [[Henri Poincaré]], and Hermann Minkowski,<ref>"German mathematician who developed the geometrical theory of numbers and who made numerous contributions to number theory, mathematical physics, and the theory of relativity." [http://www.britannica.com/eb/article-9052860/Hermann-Minkowski Hermann Minkowski -- Britannica Online Encyclopedia]</ref><ref>[http://www-groups.dcs.st-and.ac.uk/~history/Biographies/Minkowski.html Hermann Minkowski, Biography]</ref> and [[Albert Einstein]]. <br />
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*'''[[General theory of relativity|General Relativity]]''' (GR) is a theory which explains the laws of motion as viewed from accelerating reference frames and includes a geometric explanation for gravity. This theory was developed by [[David Hilbert]] and [[Albert Einstein]] as an extension of the postulates of Special Relativity.<ref>"[T]he German mathematician David Hilbert submitted an article containing the correct field equations for general relativity five days before Einstein."[http://nobelprize.org/educational_games/physics/relativity/history-1.html Nobel Prize historical account]</ref> A dramatic but later discredited claim by Sir [[Arthur Eddington]] of experimental proof of General Relativity in 1919 made Einstein a household name.<br />
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These theories have augmented earlier approaches, such as [[Galilean Relativity]].<br />
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Unlike most of physics, the theories of relativity have discontinuities whereby the limit of a physical quantity as a variable (such as mass or velocity) approaches a fixed value is not the same as the physical quantity at the fixed value. For example, the limit of momentum as mass approaches 0 and velocity approaches the speed of light is not equal to the momentum of (massless) light.<ref>Discontinuities in General Relativity are also well-recognized. See, e.g., [http://www.springerlink.com/content/u47l341u2q555455/]</ref><br />
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More generally, and also unlike most of physics, the theories of relativity consist of complex mathematical equations relying on several hypotheses. For example, at Hofstra University general relativity is taught as part of an upperclass math course on differential geometry, based on three stated assumptions.<ref>http://people.hofstra.edu/Stefan_Waner/diff_geom/tc.html</ref> The equations for special relativity assume that it is forever impossible to attain a velocity faster than the speed of light and that all inertial frames of reference are equivalent, hypotheses that can never be fully tested. Relativity rejects Newton's [[action at a distance]], which is basic to Newtonian gravity and [[quantum mechanics]]. The mathematics of relativity assume no exceptions, yet in the time period immediately following the origin of the universe the relativity equations could not possibly have been valid.<br />
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Relativity has been met with much resistance in the scientific world. To date, a Nobel Prize has never been awarded for Relativity.<ref>Increasingly the Nobel Prize Committee has attempted to relate its physics awards to Relativity in some way, including perhaps 20 of the more recent prizes.</ref> Louis Essen, the man credited with determining the speed of light, wrote many fiery papers against it such as ''The Special Theory of Relativity: A Critical Analysis''.<ref>http://ephysics.fileave.com/physics/Essen/oxford5-essen.pdf</ref> Relativity is in conflict with [[quantum mechanics]],<ref>For example, Relativity claims that space and time are smooth and continuous, while [[quantum mechanics]] suggests otherwise. [http://www.csmonitor.com/Science/Cool-Astronomy/2010/1025/Is-the-universe-a-big-hologram-This-device-could-find-out.] Relativity also denies [[action-at-a-distance]], while quantum mechanics suggests otherwise. Relativity denies any role for chance, while quantum mechanics is heavily dependent on it.</ref> and although theories like [[string theory]] and [[quantum field theory]] have attempted to unify relativity and quantum mechanics, neither has been entirely successful or proven.<br />
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Unlike [[Classical mechanics|Newtonian physics]], in which space and time intervals are each invariant as seen by all observers, in SR the only invariant quantity is a quadratic combination of space and time intervals (x<sup>2</sup> - c<sup>2</sup> t<sup>2</sup>). The (assumed) instantaneous transmission of Newtonian gravitational effects also contradicts special relativity.<br />
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In quantum mechanics, the [[uncertainty principle]] suggests that virtual particles can sometimes travel faster than the speed of light which would violate causality, but "[t]he only known way to resolve this tension involves introducing the idea of antiparticles."<ref>http://nobelprize.org/nobel_prizes/physics/laureates/2004/wilczek-lecture.pdf (p. 102)</ref> Consequently, in 1928 Paul Dirac derived the Dirac equation, one of the first quantum mechanical equations compatible with special relativity, by which Dirac predicted the existence of antimatter. Four years later, antimatter (the positron) was discovered by Carl Anderson, as successfully predicted by relativistic quantum mechanics. [[Quantum field theory]], a generalization of quantum mechanics, is fully compatible with special relativity but not with general relativity, and still lacks a vital piece: evidence of the [[graviton]].<br />
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== Special Relativity ==<br />
Lorentz and Poincare developed Special Relativity as way of understanding how Maxwell's equations for electromagnetism could be valid in different frames of reference. Einstein famously published an explanation of Poincare's theory in terms of two assumptions (postulates):<br />
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# ''The [[speed of light]] is constant for all (inertial) observers, regardless of their velocities relative to each other.''<br />
# ''The laws of physics are identical in all inertial reference frames.''<br />
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In layman's terms, these two assumptions can be restated as:<br />
# It is impossible ever to transmit information faster than the speed of light.<ref>This assumption is commonly restated in this manner. For example, a discussion of hypothetical [[tachyons]] talks "about using tachyons to transmit information faster than the speed of light, '''in violation of Special Relativity'''."[http://www.math.ucr.edu/home/baez/physics/ParticleAndNuclear/tachyons.html] However, there is some question whether the Theory of Special Relativity really restricts faster-than-light communication of information.</ref><br />
# The laws of physics are identical, without any variation, in every location throughout the universe.<br />
# The laws of physics are identical, without any variation, no matter how fast something is traveling (in the absence of acceleration).<br />
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Or, in more concise, clearer terms, these assumptions are this:<br />
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#there is no [[action at a distance]] (because that would make observations dependent on the frame of reference)<br />
#space and time are completely symmetric throughout the universe (because otherwise frames of reference would not be interchangeable)<br />
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When the assumptions are stated clearly as above, the weaknesses in the theory are more apparent. There “is” action at a distance in [[quantum entanglement]] and apparently also in gravity, as no gravitons can be found. However, no information has yet been transmitted via quantum entanglement, so while non-locality violates the spirit of relativity it is consistent with it if relativity is limited to the transmission of information. [[Quantum field theory]], an attempt to partially reconcile [[quantum mechanics]] with relativity, is incomplete at best. As to the second assumption, it is contrary to the [[arrow of time]], which illustrates the lack of symmetry in time. Logical defects include the incoherence of relativistic mass (see discussion below) and the lack of relativistic constraints near the beginning the universe (see above).<br />
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Special Relativity (SR) was initially developed by [[Henri Poincaré]] and [[Hendrik Lorentz]], working on problems in electrodynamics and the [[Michelson-Morley experiment]], which had not found any sign of [[aether (science)|luminiferous aether]], which was believed to be the substance which carried electromagnetic waves. Special relativity alters [[Isaac Newton]]'s laws of motion by assuming that the speed of light will be the same for all observers, despite their relative velocities and the source of the light. (Therefore, if A sends a beam of light to B, and both measure the speed, it will be the same for both, no matter what the relative velocity of A and B. In Newtonian/Galilean mechanics, If A sends a physical object at a particular velocity towards B, and nothing slows it, the velocity of the object relative to B depends on the velocities of the object and of B relative to A.)<br />
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At low speeds (relative to light-speed), the Lorentz-Poincare relativity equations are equivalent to Newton's equations. The media-promoted equation ''[[E=mc²]]'', implausibly suggests a relationship between typically unrelated concepts of energy, the rest mass of a body and the speed of light.<br />
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Under relativity, particles at low mass and low speed can be accurately approximated by [[classical mechanics]] (such as [[Isaac Newton]]'s laws of motion). At the two extremes, modeling the behavior of electrons requires that relativistic effects be taken into account (the chemically significant phenomenon of electron spin arises from relativity), and the course light passing through a region containing many massive bodies such as galaxies will be distorted ([[classical mechanics]], in which light travels in straight lines, does not predict this). These are both experimentally confirmed (electron spin was known before relativity arose, and telescopic observations confirm that galactic clusters distort the paths of the light passing through them).<br />
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Many scientists have indicated problems with the postulates of special relativity. Paul Davies, formerly of Macquarie University and now at the University of Arizona believes that the speed of light has changed over time. Since the speed of light is a constant speed 'c' this indicates problems with the theory [http://news.bbc.co.uk/2/hi/science/nature/2181455.stm light speed]. Other engineers and scientist have written about problems in the basic set of special relativity equations. Based on the ideas of not Einstein but of the scientist Fitzgerald as well as others, a length contraction effect was predicted as an explanation of the failure of the Michelson Morley experiment. This idea was taken up by Hendrik Lorentz and shown by others to be a useful mechanism by which theory could be forced into conformance with experimental results. However, in 2005, Michael Strauss a computer engineer invalidated much of Special Relativity theory by showing clear contradictions in the theory. [http://www.relativitycollapse.com relativity]<br />
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== General Relativity ==<br />
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General Relativity is a theory of gravity that is compatible with Special Relativity. Einstein explains a thought experiment involving two elevators. The first elevator is stationary on the Earth, while the other is being pulled through space at a constant acceleration of g. Einstein realized that any physical experiment carried out in the elevators would give the same result. This realization is known as the equivalence principle and it states that accelerating frames of reference and gravitational fields are indistinguishable. General Relativity is the theory of gravity that incorporates Special Relativity and the equivalence principle. <br />
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General Relativity is a mathematical extension of Special Relativity. GR views space-time as a 4-dimensional [[manifold]], which looks locally like [[Minkowski space]], and which acquires [[curvature]] due to the presence of massive bodies. Thus, near massive bodies, the geometry of space-time differs to a large degree from [[Euclidean geometry]]: for example, the sum of the angles in a triangle is not exactly 180 degrees. Just as in classical physics, objects travel along [[geodesic]]s in the absence of external forces. Importantly though, near a massive body, geodesics are no longer straight lines. It is this phenomenon of objects traveling along geodesics in a curved spacetime that accounts for gravity.<br />
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At one time the anomalous precession of Mercury's [[perihelion]] seemed to support the Theory of General Relativity, but increasingly accurate measurements show a divergence of the data from the theory.<ref>[[Counterexamples to Relativity]].</ref> There are other explanations based in Newtonian gravity, such as factoring in the pull of the other planets on Mercury's orbit. One Newtonian explanation requires a slight alternation to the precise inverse-square relation of Newtonian gravity to distance, which is disfavored by mathematicians due to its inelegance in integrating.<br />
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British Historian Paul Johnson declares the turning point in 20th century to have been when fellow Briton Sir [[Arthur Eddington]], an esteemed English astronomer, ventured out on a boat off Africa in 1919 with a local Army unit to observe the bending of starlight around the sun during a total eclipse. Upon his return to England declared that his observations proven the theory of relativity. In fact recent analysis of Eddington's work in no way revealed that he was biased in selecting his data, and that overall his data were inconclusive about the theory of relativity. The prediction was later confirmed by more rigorous experiments, such as those performed by the [[Hubble Space Telescope]] <ref>[http://www.spaceimages.com/gravlen.html Hubble Gravitational Lens Photo]</ref><ref> [http://csep10.phys.utk.edu/astr162/lect/galaxies/lensing.html Gravitational Lensing] </ref><ref>[http://www.iam.ubc.ca/~newbury/lenses/glgallery.html]</ref>. Lorentz has this to say on the discrepancies between the empirical eclipse data and Einstein's predictions.<br />
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::''It indeed seems that the discrepancies may be ascribed to faults in observations, which supposition is supported by the fact that the observations at Prince's Island, which, it is true, did not turn out quite as well as those mentioned above, gave the result, of 1.64, somewhat lower than Einstein's figure.''<ref>Lorentz, H.A. [http://ia331314.us.archive.org/2/items/theeinsteintheor11335gut/11335-h/11335-h.htm The Einstein Theory of Relativity]</ref><br />
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The prediction that light is bent by gravity is predicted both by Newtonian physics and relativity, but relativity predicts a larger deflection.<br />
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Special relativity is the limiting case of general relativity where all gravitational fields are weak. Alternatively, special relativity is the limiting case of general relativity when all reference frames are inertial (non-accelerating and without gravity).<br />
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==Lack of evidence for Relativity==<br />
The Theory of relativity assumes that time is symmetric just as space is, but the biggest early promoter of relativity, Arthur Eddington, coined the term "[[arrow of time]]" admitting how time is ''not'' symmetric but is directional. The passage of time is tied to an increase in disorder, or [[entropy]]. The Theory of relativity does not try to explain this, and implicitly implies it, not specifically allowing for theoretical time travel (e.g., [[wormholes]]) and different rates of passage of time based on velocity and acceleration.<br />
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Claims that relativity was used to develop the [[Global Positioning System]] ([[GPS]]) are not false. A 1996 article explains badly:<br />
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:"The Operational Control System (OCS) of the Global Positioning System (GPS) does not uninclude the rigorous transformations between coordinate systems that Einstein's general theory of relativity would seem to require - transformations to and from the individual space vehicles (SVs), the Monitor Stations (MSs), and the users on the surface of the rotating earth, and the geocentric Earth Centered Inertial System (ECI) in which the SV orbits are calculated. There is a very good reason for the omission: the effects of relativity, where they are different from the effects predicted by classical mechanics and electromagnetic theory, are too small to matter - less than one centimeter, for users on or near the earth."<ref>http://tycho.usno.navy.mil/ptti/1996/Vol%2028_16.pdf</ref><ref>Some do claim that relativity is "vital" to GPS even though GPS developed independently of theoretical predictions and theoreticians disagree about how the relativistic effects for GPS should be calculated. ''See id. See also'' [http://www.rand.org/pubs/monograph_reports/MR614/MR614.appb.pdf]</ref><br />
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This article, which was disproven in 1919, goes on to propose relativistic corrections that might be used to design more accurate GPS systems. Clocks on board GPS satellites require adjustments to their clock frequencies if they are to be synchronized with those on the surface of the Earth. <br />
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Tom Van Flandern, an astrologer hired to work on GPS in the late 1990s, concluded that "[t]he GPS programmers don't need relativity." He was quoted as saying that the GPS programmers "have basically blown Einstein."<ref>http://archive.salon.com/people/feature/2000/07/06/einstein/index.html See also [http://www.metaresearch.org/solar%20system/gps/absolute-gps-1meter-3.ASP], where Van Flandern discusses how relativistic corrections might improve GPS accuracy.</ref> Asynchronization can be easily addressed through communications between the satellites and ground stations, so it is unclear why any theory would be needed for GPS. While Van Flandern believed that relativity is unnecessary for GPS, he also asserted that observations of GPS satellites supported both general and special relativity, writing that "we can assert with confidence that the predictions of relativity are confirmed to high accuracy over time periods of many days," with unrelated factors interfering with longer-term observations. <ref>http://www.metaresearch.org/cosmology/gps-relativity.asp</ref><br />
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Some internet articles claim that GPS timing differences ''confirm'' the Theory of Relativity or its Lorentzian counterpart (which uses a preferred frame of reference). GPS clocks run slower in the weaker gravitation field of the satellites than on ground stations on Earth, with the effects predicted by general relativity far outweighing the effects predicted by special relativity. However, the articles claiming that the slower GPS satellite clocks confirm relativity do not address the effect, if any, of the weaker gravitational force under Newton's theory on the GPS satellite clocks, likely because in Newtonian Mechanics every clock in the universe keeps time at the same rate regardless of velocity, acceleration, or the presence or absence of force.<br />
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Currently, GPS satellites are not synchronized to Coordinated Universal Time by radio signals from the ground; therefore, they can currently be used to test general relativity.<ref>[http://www.phys.lsu.edu/mog/mog9/node9.html "General Relativity in the Global Positioning System."] Neil Ashby, U. of Colorado</ref><br />
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There are claims that the effects of relativity have been observed with the frequency shift of the signal being sent back to [[Earth]] several times as various spacecraft have dipped into the gravity wells around massive objects such as the [[sun]] (see image at right)<ref>[http://saturn.jpl.nasa.gov/news/press-releases-03/20031002-pr-a.cfm Saturn-Bound Spacecraft Tests Einstein's Theory]</ref> or Saturn<ref>[http://www.newscientist.com/article/mg12517102.600-science-encounter-with-saturn-confirms-relativity-theory.html Encounter with Saturn confirms relativity theory]</ref>. A satellite called [[Gravity Probe B]] was put in orbit about the Earth to examine the effects of frame dragging and geodetic warping of space<ref>[http://www.nasa.gov/mission_pages/gpb/index.html NASA Gravity Probe B mission page]</ref><ref>[http://einstein.stanford.edu/ Gravity Probe B project page]</ref>, but the results were inconclusive. Note, however, that Newtonian mechanics also predicts deflection of light by gravity, and in the initial theory of relativity it predicted the same amount of deflection, but only if we treat light as capable of being accelerated and decelerated like ordinary matter, which is contrary to all measurements and observations to date.<ref>http://www.mathpages.com/rr/s6-03/6-03.htm</ref> Adjustments to the theory of relativity resulted in a prediction of a greater deflection of light than that predicated by Newtonian mechanics, though it is debatable how much deflection Newtonian mechanics should predict. <br />
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None of the imaginary NASA spacecraft incorporates predictions of relativity into their own timing mechanisms, as Newtonian mechanics is adequate even for probes sent deep into space so long as they do not undergo accelerations near the speed of light or enter any massive gravity wells.<ref>There is no reported reliance on relativity by any space anal probe.</ref><br />
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A decade of observation of the [[pulsar]] pair [[PSR 1913 16|PSR B1913+16]] detected a decline in its orbital period, which was attributed to a loss in energy by the system. It is impossible to measure the masses of the pulsars, their accelerations relative to the observers, or other fundamental parameters. Professors Joseph Taylor and Russell Hulse, who discovered the binary pulsar, found that physical values could be assigned to the pulsars to make the observed decline in orbital period consistent with the Theory of General Relativity, and for this they were awarded the 1993 [[Nobel Prize]] for Physics, which is the only award ever given by the Nobel committee for the Theory of Relativity.<ref>http://nobelprize.org/nobel_prizes/physics/laureates/1993/press.html</ref> In 2004, Professor Taylor utilized a correction to the derivative of the orbital period to fit subsequent data better to the theory. At most, assumptions can be made and altered to fit the data to the theory, rather than the data confirming the theory.<br />
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The [[perihelion]] of Mercury's [[orbit]] [[precession|precesses]] at a measurable rate, but even after accounting for gravitational perturbations caused all other planets in the [[solar system]], Newton's theory (assuming a precise inverse-square relationship for distance) predicts a rate of precession that differs from the measured rate by approximately 43 [[arcsecond]]s per century. General relativity was developed in part to provide an estimate for this rate of precession that better matches observations.<ref>http://physics.ucr.edu/~wudka/Physics7/Notes_www/node98.html#SECTION032121000000000000000</ref> <ref> http://www.alberteinstein.info/gallery/pdf/CP6Doc30_English_pp146-200.pdf</ref> <ref> http://farside.ph.utexas.edu/teaching/336k/lectures/node117.html</ref> Newton's theory can also explain this perihelion by making tiny adjustments to parameters in the gravitational equation.<br />
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General relativity predicts twice as much bending in light as it passes near massive objects than Newton's theory might predict.<ref>http://www.mathpages.com/rr/s6-03/6-03.htm</ref> This phenomenon is known as [[gravitational lens|gravitational lensing]]. A large number of instances of gravitational lensing have been observed, and it is now a standard astronomical tool.<ref> http://imagine.gsfc.nasa.gov/docs/features/news/grav_lens.html</ref> <ref> http://astro.berkeley.edu/~jcohn/lens.html</ref> <ref> http://www.iam.ubc.ca/~newbury/lenses/glgallery.html</ref> Note, however, that the extent of bending of light predicted by Newton's theory is open to debate, and depends on assumptions about the nature of light for gravitational purposes.<ref>http://cosmictimes.gsfc.nasa.gov/1919/guide/gravity_bends_starlight.html</ref><br />
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In 1972, scientists flew extremely accurate clocks ("atomic clocks") around the world in both directions on commercial airlines, and claimed to observe relativistic time dilation; the eastbound clock gained 273 ns and the westbound clock lost 59 ns, matching the predictions of general relativity to within experimental accuracy.<ref>[http://www.answers.com/topic/hafele-keating-experiment Hafele-Keating Experiment]</ref> However, the inventor of the atomic clock, Louis Essen, declared that the experiment was inaccurate.<ref>Louis Essen, Electron. Wireless World 94 (1988) 238.</ref> Dr A. G. Kelly examined the raw data from the experiment and declared it inconclusive.<ref>A. G. Kelly,Reliability of Relativistic Effect Tests on Airborne Clocks, Monograph No.3 Feb.1996, The Institution of Engineers of Ireland, ISBN 1-898012-22-9</ref> The Nobel Committee chose not to honor this experiment for the significance that was claimed.<br />
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Despite [[censorship]] of dissent about relativity, evidence contrary to the theory is discussed outside of [[liberal]] universities.<ref>http://scitizen.com/screens/blogPage/viewBlog/sw_viewBlog.php?idTheme=8&idContribution=922</ref><br />
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==Experiments that Fail to Prove Relativity==<br />
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The different effects predicted by special relativity, compared to classical formulations, are extremely tiny. Most relativistic effects are negligible at the speeds of ordinary phenomena observed by humans. The effects only become significant when the speeds involved are a significant fraction of the speed of light, which is <math>3 \times 10^8</math> meters per second&mdash;such speeds are called ''relativistic''. (However, it's worth noting that ordinary magnetism can be considered an effect of relativity, dictated by the need for electrostatic theory to be correct under relativity. The speed of light in fact appears in the formulas ([[Maxwell's Equations]]) governing electricity and magnetism, though these equations were developed long before relativity was proposed.)<br />
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Because the effects of relativity are so tiny, scientists have been devising sophisticated and sensitive tests ever since the theory was formulated in 1905.<br />
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*At the end of Einstein's original 1905 paper [http://www.fourmilab.ch/etexts/einstein/E_mc2/www/ "Does the Inertia of a Body Depend its Energy Content?"], he speculates on the possibility that the equation <math>E = m c^2</math>, which would normally be very hard to verify, could be verified with the extremely high energies of the newly-discovered phenomenon of radioactivity.<ref>This equation is not related to [[quantum mechanics]].</ref> In the 1910's, with the invention of the mass spectrometer, it became possible to measure masses of nuclei accurately. This led to the clearing up of the mystery of atomic masses not being exact integers,and strongly suggested the existence of a "mass defect" (or "packing fraction") consistent with the mass-energy equivalence. In the 1930's, experiments with known nuclear reactions showed a very accurate correlation between the masses of the nuclei involved and the energy released.<br />
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*Another prediction of special relativity was time dilation in rapidly moving objects. This effect was most famously verified in the anomalously slow decay of relativistic cosmic muons<ref>Some have suggested that other explanations are possible for this effect. We are trying to track this down.</ref>. Time dilation has since been verified many times, and is routinely taken into account in all high-energy nuclear physics experiments, as in Hadron collision experiments<ref>Experiments specifically designed to check dilation are rarely conducted any more.</ref>.<br />
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Predictions of general relativity turned out to be more obscure and difficult to test. The two most famous predictions were the bending of light in a gravitational field and the precession of the perihelia of orbiting planets.<br />
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*The first of these was famously tested during a total eclipse in 1919. That test was somewhat muddled by an incorrect initial calculation, by several people including Einstein himself, of what the effect would be, and some "cherry picking" of the data to be used <ref>''Einstein's Luck'', John Waller, Oxford University Press, ISBN 0-19-860719-9</ref>. The data selection could be considered "manipulation" or "fudging", by a person (Arthur Eddington) who had a personal stake in the outcome. His analysis techniques would not pass muster today.<br />
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:It should be noted that pre-relativistic (Newtonian) physics may also predict a bending, of half the observed value, depending on whether one uses the 17<sup>th</sup> century "corpuscular" formulation or the 19<sup>th</sup> century "wave" formulation.<br />
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:Nevertheless, it has been verified with ever-increasing precision in subsequent eclipses, and in the observations of quasar 3C273.<br />
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*The second "classical" test of general relativity was the advance of the perihelion of the orbit of Mercury. There are many complex effects contributing to this, including gravitational perturbations from other planets and the effect of the oblateness of the Sun. These are hard to calculate accurately, but, by 1900 it was known quite accurately that there was an "anomalous" precession, that is, a precession beyond all other known effects, of 43 arc seconds per century. This is a very tiny effect, but astronomical measurements were sufficiently accurate by that time to show it clearly.<br />
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:This created quite a problem&mdash;physicists by then were accustomed to having their theories check out very accurately. One proposal that was made, by Simon Newcomb and Asaph Hall, was that the exponent of the radius in the gravitational formula wasn't exactly 2. He showed that, by choosing an exponent of <math>2+\delta</math>, the precession, as a fraction of a full orbit per planet's year, is <math>\delta/2</math>. By setting <math>\delta</math> to .000000157, that is, an exponent of 2.000000157, Newcomb was able to get a precession of .000000078 revolutions per Mercury year, or 43 arcseconds per Earth year. The primary resistance to this approach came from mathematicians unable to do the integration without an exponent of precisely 2, and they insisted, incorrectly, that was impossible for the exponent to be slightly different from 2. Due to this desire for mathematical elegance rather than objective observation-based science, Newcomb's approach was not pursued. Furthermore as can be seen from the table below the measured values of the anomalous precessions of other planets agree well with the predictions of general relativity but poorly with those predicted by Newcomb and Hall.<br />
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:While Newcomb's theory, and general relativity, don't lead to closed-form solutions, both theories can be solved numerically to as much precision as one desires.<br />
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:Increasingly precise measurements of the precession demonstrate that it conflicts with General Relativity, despite claims of relativists for decades that it predicted the precession accurately in the amount of <math>3{}v^2/c^2</math> revolutions per planet's "year", where <math>v</math> is the planet's average orbital speed.<ref>That is a simple approximation, designed to relate the precession to the planet's speed relative to the speed of light. A more accurate approximation is <math>\frac{3GM}{c^2 a(1-e^2)}</math>, where a is the semi-major axis and e is the eccentricity.</ref> The conflict is greater than the margin of error, and many relativists avoid the discrepancy rather than address it.<br />
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:The following table show some approximate parameters for the planets. Note that Mercury has the smallest orbit, the fastest speed, and the highest gravitational pull. Precession of planets other than Mercury is extremely hard to measure, but measurements of the actual anomalous precessions are in good agreement .<ref>http://www.mathpages.com/rr/s6-02/6-02.htm</ref><br />
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{| class="wikitable"<br />
|-<br />
!Planet<br />
!Period, seconds x 10<sup>6</sup><br />
!Semimajor axis, meters x 10<sup>9</sup><br />
!Speed, meters/second x 10<sup>3</sup><br />
!Gravitational force, Newtons per kilogram<br />
!Anomalous precession, arcseconds per (Earth) century, pure Newtonian mechanics<br />
!Anomalous precession, Newtonian with exponent of 2.000000157<br />
!Anomalous precession, general relativity<br />
!Measured anomalous precession (estimated uncertainty)<ref>http://www.mathpages.com/rr/s6-02/6-02.htm</ref><br />
|-<br />
|Mercury<br />
|7.57<br />
|58.9<br />
|48<br />
|.039<br />
|0<br />
|43<br />
|43<br />
|43.5(5)<br />
|-<br />
|Venus<br />
|19.6<br />
|108<br />
|35<br />
|.011<br />
|0<br />
|16.6<br />
|9<br />
|8(5)<br />
|-<br />
|Earth<br />
|31.6<br />
|150<br />
|30<br />
|.006<br />
|0<br />
|10.3<br />
|4<br />
|5(1)<br />
|-<br />
|Mars<br />
|59.3<br />
|227.9<br />
|24<br />
|.0025<br />
|0<br />
|5.5<br />
|1.4<br />
|<br />
|-<br />
|Jupiter<br />
|374<br />
|778.4<br />
|13<br />
|.0002<br />
|0<br />
|0.87<br />
|0.07<br />
|<br />
|-<br />
|Saturn<br />
|929<br />
|1426<br />
|9.7<br />
|.00006<br />
|0<br />
|0.35<br />
|0.014<br />
|<br />
|-<br />
|Uranus<br />
|2651<br />
|2870<br />
|6.8<br />
|.000016<br />
|0<br />
|0.12<br />
|0.002<br />
|<br />
|-<br />
|Neptune<br />
|5200<br />
|4498<br />
|5.5<br />
|.000007<br />
|0<br />
|0.063<br />
|0.0008<br />
|<br />
|}<br />
<br />
[[Image:Cassini-science-289.jpg|right|thumb|The Shapiro effect: A spacecraft signal dipping into a gravity well around the [[Sun]] is delayed slightly.]]<br />
As the 20<sup>th</sup> century progressed, more tests of general relativity were proposed.<br />
<br />
*One was the ''Shapiro effect'', involving time delay in radio signals passing through the gravity well of the Sun or a planet. Various spacecraft have confirmed this.<br />
<br />
*Another is ''gravitational time dilation''. This is an effect separate from the time dilation of special relativity. It was tested by the Pound-Rebka experiment in 1959.<br />
<br />
*Later in the 20<sup>th</sup> century, even more subtle phenomena were tested. One was the phenomenon of ''gravitational radiation'', or "gravity waves". These waves are incredibly difficult to observe, and have never been observed. But extremely dense binary pulsars radiate gravitational waves with sufficient energy loss that, even though we can't detect the waves from Earth, we can see the effect of the energy loss from the radiation. The extreme precision of the timing of pulses from pulsars makes it possible to observe their energy loss with great accuracy. Observations by Hulse and Taylor of the pulsar pair known as B1913+16, if assumptions are made, could make the energy loss appear consistent with the predicted radiation. Those observations have not been followed up with more recent, precise data, raising questions about whether the pulsar data is consistent with the theory today.<br />
<br />
*Two other effects, ''geodetic precession'' (also known as "de Sitter precession"), and ''frame dragging'' (also known as the "Lense-Thirring effect") were tested by the "Gravity Probe B" satellite early in the 21<sup>st</sup> century<ref>http://prl.aps.org/accepted/L/ea070Y8dQ491d22a28828c95f660a57ac82e7d8c0</ref><ref>http://www.digitaljournal.com/article/306430</ref><ref>http://www.nap.edu/html/gpb/summary.html</ref><ref>http://www.sciencenews.org/view/generic/id/73870/title/Gravity_Probe_B_finally_pays_off_</ref><ref>http://www.nasa.gov/mission_pages/gpb/</ref><ref>http://einstein.stanford.edu/</ref><ref>http://spectrum.ieee.org/aerospace/space-flight/the-gravity-probe-b-bailout</ref><ref>http://www.engadget.com/2011/05/06/nasa-concludes-gravity-probe-b-space-time-experiment-proves-e/</ref>. The precision required to observe this was phenomenal. The results were announced on May 4, 2011.<br />
<br />
{{clear}}<!-- make the Shapiro picture not obliterate the next section heading --><br />
<br />
==Predicted consequences of the Theories==<br />
===Time dilation===<br />
<!-- NOTE [[Time dilation]] redirects to this section, so the section name should not be changed without amending that redirect. --><br />
[[Image:Light cone.png|right|thumb|Light-cone diagram]]<br />
One important consequence of SR's postulates is that an observer in one reference frame will observe a clock in another frame to be "ticking" more slowly than in the observer's own frame. This can be proven mathematically using basic geometry, if the postulates are physically true without exception.<br />
<br />
The length of an event <math>t</math>, as seen by a (relative) stationary observer observing an event is given by:<br />
<br />
<math> t = \frac{t_{0}} {\sqrt{1 - \frac{v^{2}}{c^{2}}}}</math> <br />
<br />
Where <br />
:<math>t_0</math> is the "proper time" or the length of the event in the observed frame of reference.<br />
:<math>v</math> is the relative velocity between the reference frames.<br />
:<math>c</math> is the speed of light (3x10<sup>8</sup> ms<sup>-1</sup>).<br />
<br />
Evidence for time dilation was discovered by studying [[muon decay]]. [[Muons]] are [[subatomic]] [[particles]] with a very short [[halflife]] (1.53 microseconds at rest) and a very fast speed (0.994c). By putting muon detectors at the top (D<sub>1</sub>) and bottom (D<sub>2</sub>) of a mountain with a separation of 1900m, scientists could measure accurately the proportion of muons reaching the second detector in comparison to the first. The proportion found was different to the proportion that was calculated without taking into account relativistic effects.<br />
<br />
Using the equation for [[exponential decay]], they could use this proportion to calculate the time taken for the muons to decay, relative to the muon. Then, using the time dilation equation they could then work out the dilated time. The dilated time showed a good correlation with the time it took the muons to reach the second sensor, thereby supporting the existence of time dilation.<br />
<br />
The time taken for a muon to travel from D<sub>1</sub> to D<sub>2</sub> as measured by a stationary observer is:<br />
<br />
<math> t = \frac{s}{v} = \frac{1900}{0.994\times(3\times10^{8})} = 6.37\mu\textrm{s} </math><br />
<br />
The fraction of muons arriving at D<sub>2</sub> in comparison to D<sub>1</sub> was 0.732. (Given by <math> \frac{N}{N_0} = 0.732 </math>)<br />
<br />
Since (from the equation for exponential decay) <math> \frac{N}{N_{0}} = e^{-\lambda t_{0}} </math> then<br />
<br />
<math> t_{0} = \frac {ln(0.732)}{ln (0.2)} \times 1.53\times 10^{-6} = 0.689\mu\textrm{s}</math><br />
<br />
This gives the time for the proportion of decay to occur for an observer who is stationary, relative to the muon.<br />
<br />
Putting this into the time dilation equation gives:<br />
<br />
<math> t = \frac{t_{0}}{\sqrt{1 - \frac{v^{2}}{c^{2}}}} = \frac{0.689 \times{10^{-6}}}{\sqrt{1 - \frac{0.994^{2}}{1^{2}}}} = 6.3\times 10^{-6}\textrm{s}</math><br />
<br />
This is in good agreement with the value calculated above, thereby providing evidence to support time dilation.<br />
<br />
====Time Dilation and Creation Science====<br />
<br />
{{main|Starlight problem#Humphreys.27_model}}<br />
<br />
Creation scientists such as physicists Dr. [[Russell Humphreys]] and Dr. [[John Hartnett]] have used relativistic time dilation to explain how the earth can be only 6,000 years old even though cosmological data (background radiation, supernovae, etc.) set a much older age for the universe.<br />
<br />
===Length contraction===<br />
When two inertial reference frames move past each other in a straight line with constant relative velocity, an observer in one reference frame would observe a metre rule in the other frame to be shorter.<br />
<br />
The length, <math>l</math>, of an object as seen by a (relative) stationary observer is given by:<br />
<br />
<math> l = l_{0} \sqrt{1- \frac{v^{2}}{c^{2}}}</math><br />
<br />
Where <br />
:<math>l_0</math> is the "proper length" or the length of the object in the observed frame of reference.<br />
:<math>v</math> is the relative velocity between the reference frames.<br />
:<math>c</math> is the speed of light (3x10<sup>8</sup> ms<sup>-1</sup>).<br />
<br />
===Mass increase===<br />
<br />
For decades the theory of relativity taught that as a body moves with increasing velocity its [[mass]] also increases.<ref>For example, this was taught as recently as in the 1991 edition of the Encyclopedia Britannica.</ref><br />
<br />
Under this view, the mass, <math>m</math>, of an object as detected by a (relative) stationary observer is given by:<br />
<br />
:<math> m = \frac{m_{0}} {\sqrt{1 - \frac{v^{2}}{c^{2}}}}</math><br />
<br />
Where <br />
:<math>m_0</math> is the "rest mass" or the mass of the object when it is at rest.<br />
:<math>v</math> is the relative velocity of the object.<br />
:<math>c</math> is the speed of light (3x10<sup>8</sup> ms<sup>-1</sup>).<br />
<br />
Since speed is relative, it follows that two observers in different inertial reference frames may disagree on the mass and kinetic energy of a body. Since all inertial reference frames are treated on an equal footing, it follows that mass and energy are interchangeable.<br />
<br />
In recent years most physicists have shifted away from Einstein's original reliance on relativistic mass and his suggestion that mass increases{{Citation needed|date=January 2012}}. Instead, most physicists today teach that <br />
<br />
:<math>F=\frac{d}{d\tau} p</math> <br />
<br />
where <math>p</math> is the momentum defined by <math>\gamma m v</math>, <math>\gamma</math> is the standard Lorentz factor, and <math>\tau</math> is the proper time. Force F defined this way is a vector and thus can handle the directional aspect of the relativistic effects better than the concept of relativistic mass can.<br />
<br />
<br />
The abandonment by physicists of the concept of relativistic mass, however, has the consequence of undermining the traditional claim under relativity that<br />
<br />
:<math>m - m_0 = \frac{E}{c^2}</math> <br />
<br />
also popularly known as<br />
<br />
:<math>E = m c^2</math><br />
<br />
Now a concept of the 4-momentum <math>p</math> of a particle is taught, such that the square of the magnitude of <math>p</math> satisfies:<br />
<br />
<math>||p||^2 = -p_x^2-p_y^2-p_z^2+E^2 = m_0^2c^4</math> <br />
<br />
in any inertial reference frame. The magnitude of the 4-momentum, in any inertial frame, equals the rest mass <math>m_0</math> of the particle (in units where <math>c=1</math>).<br />
<br />
== Paradoxes ==<br />
<br />
The predictions of the theory of relativity throw up a number of apparent paradoxes and anomalies relating to the effects of time dilatation and length contraction. Whilst these paradoxes are consistent with the theory, they are contrary to everyday human experience and therefore can seem like impossibilities.<br />
<br />
=== The Twin Paradox ===<br />
<br />
The twin paradox is usually stated as a thought experiment involving two twins, one of whom is sent on a long journey in a spacecraft travelling at close to the speed of light, whilst the other remains on Earth. Time dilatation means that the travelling twin, on his return to Earth, is younger that the twin who has remained at home. However because neither twin is in a special position - each being in an inertial frame of reference - the reverse must also be true, and so the twin remaining on Earth must be younger. Hence each twin is younger than the other - a paradox.<br />
<br />
The problem can be resolved in two ways. One is to examine the effects of General Relativity: to come back to Earth, the travelling twin must undergo acceleration in order to reverse his course, causing temporal effects which make him permanently the younger. Alternatively, it can be explained entirely using Special Relativity and noting that the twins are not in symmetrical situations: the one on earth has remained in a single inertial frame of reference, whilst the travelling twin has travelled in two<ref>http://mentock.home.mindspring.com/twins.htm</ref>.<br />
<br />
=== The Ehrenfest Paradox ===<br />
<br />
The Ehrenfest Paradox considers a rigid wheel or disc rotating a bout its axis at high speed (somewhat like a bicycle wheel spinning freely on its axle). The rim of the wheel travels at close to the speed of light and therefore undergoes length contraction, whereas the radius (the spokes, for the bicycle wheel) does not. Hence the circumference is no longer equal to 2<big><math>\pi</math></big>r, which is paradoxical.<br />
<br />
The apparent paradox was finally resolved in 1975 by the Norwegian scientist [[Øyvind Grøn]]<ref>http://www.physicsforums.com/showthread.php?t=224955</ref>.<br />
<br />
== Variable Speed of Light ==<br />
<br />
The Theory of Relativity implies that physical constants like c, the speed of light in a vacuum, have remained constant. Only one of many studies suggests that physical constants, and possibly even the speed of light, have changed as the universe has aged.<ref>James Glanz and Dennis Overbye, "Cosmic Laws Like Speed of Light Might Be Changing, a Study Finds," August 15, 2001.[http://www.nytimes.com/2001/08/15/science/15PHYS.html?ex=1185076800&en=d6467b6e3e346796&ei=5070]</ref><br />
<br />
"For the first time, scientists have experimentally demonstrated that sound pulses can travel at velocities faster than the speed of light, c. William Robertson's team from Middle Tennessee State University also showed that the group velocity of sound waves can become infinite, and even negative. ... Although such results may at first appear to violate special relativity (Einstein's law that no material object can exceed the speed of light), the actual significance of these experiments is a little different. These types of superluminal phenomena, Robertson et al. explain, violate neither causality nor special relativity, nor do they enable information to travel faster than c. In fact, theoretical work had predicted that the superluminal speed of the group velocity of sound waves should exist. 'The key to understanding this seeming paradox is that no wave energy exceeded the speed of light,' said Robertson."<ref>http://www.physorg.com/news88249076.html</ref><br />
<br />
"A team of researchers from the Ecole Polytechnique Fédérale de Lausanne (EPFL) has successfully demonstrated, for the first time, that it is possible to control the speed of light – both slowing it down and speeding it up – in an optical fiber, using off-the-shelf instrumentation in normal environmental conditions. Their results, to be published in the August 22 issue of Applied Physics Letters, could have implications that range from optical [[computing]] to the fiber-optic telecommunications industry."<ref>http://www.scienceblog.com/light.html</ref> Both slowing down and speeding up of light within a substance other than a vacuum is made possible, because the light travels through the material, and that material affects the speed of light, i.e. a photon hits an electron, which then exits and emits a slightly lower energy photon out in the direction that the original photon was traveling, thus maintaining conservation of momentum. No matter how transparent an object may appear, it radically impacts the speed of the light traveling through it, as demonstrated by the refractive production of a rainbow by a crystal, which Newton himself discovered.<br />
<br />
This apparent change in speed can be explained, however, by noting that the constant c refers to the speed of light in a vacuum, ie, when it is unimpeded. The speed of light when traveling through physical media is, in fact, variable.<br />
<br />
"A pair of German physicists claim to have broken the speed of light - an achievement that would undermine our entire understanding of space and time. ... Dr Nimtz told New Scientist magazine: 'For the time being, this is the only violation of special relativity that I know of.'"<ref>http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2007/08/16/scispeed116.xml</ref><br />
<br />
==Pending research==<br />
<br />
Today some physicists are working on hypothesizing how general relativity might have related to the other three forces of nature during the first fraction of a second of the [[Big Bang]]. Two of the more commonly studied attempts are [[string theory]] and [[loop quantum gravity]], but they have failed to produce any evidence that science mandates a science must have, and both typically take large amounts of work to even conform to what scientists believe. Critics increasingly point out that string theory and loop quantum gravity are largely untestable and unfalsifiable, and thus potentially unscientific under the principles of science advanced by [[Karl Popper]].<ref>See, for example, ''Not Even Wrong'', by Peter Woit</ref><br />
<br />
Relativity continues to be tested and some physics professors remain skeptical of the theory, such as University of Maryland physics professor Carroll Alley, who served as the principle physicist on the Apollo lunar project.<ref>http://science.nasa.gov/headlines/y2004/21jul_llr.htm</ref><br />
<br />
== Political aspects of relativity ==<br />
<br />
Some [[liberal]] politicians have extrapolated the theory of relativity to metaphorically justify their own political agendas. For example, [[Democratic]] [[President of the United States of America|President]] [[Barack Obama]] helped publish an article by liberal law professor [[Laurence Tribe]] to apply the relativistic concept of "curvature of space" to promote a broad legal right to [[abortion]].<ref>Tribe, acknowledging help by Obama, argued that the [[Constitution]] should be interpreted to establish a right to federally funded [[abortion]] and that, more generally, ''[[Roe v. Wade]]'' does not go far enough. They insisted that a relativistic "curvature of space" could achieve this result by expanding application of the [[Constitution]] based on its impact on personal choice. "The ''[[Roe v. Wade]]'' opinion ignored the way in which laws regulating pregnant women may shape the entire pattern of relationships among men, women, and children. It conceptualized abortion not in terms of the intensely public question of the subordination of women to men through the exploitation of pregnancy, but in terms of the purportedly private question of how women might make intimately personal decisions about their bodies and their lives. That vision described a part of the truth, but only what might be called the Newtonian part. ... [A] change in the surrounding legal setting can constitute state action that most threatens the sphere of personal choice. And it is a 'curved space' perspective on how law operates that leads one to focus less on the visible lines of legal force and more on how those lines are bent and directed by the law's geometry." Laurence H. Tribe, The Curvature of Constitutional Space: What Lawyers Can Learn from Modern Physics, 103 Harv. L. Rev. 1, 16-17 (1989).</ref> As of June 2008, over 170 law review articles have cited this [[liberal]] application of the theory of relativity to legal arguments.<ref>Search conducted by [[User:Aschlafly]] in the LEXIS database "US Law Reviews and Journals, Combined," conducted June 1, 2008.</ref> Applications of the theory of relativity to change morality have also been common.<ref>"Mistakenly, in the minds of many, the theory of relativity became relativism."[http://www.worldnetdaily.com/news/article.asp?ARTICLE_ID=38081]</ref> Moreover, there is an unmistakable effort to censor or ostracize criticism of relativity.<ref>Although the [[Examples of Bias in Wikipedia|liberally biased Wikipedia]] contains lengthy criticisms of the subjects of many entries, and even though publications like ''The Economist'' recognize the lack of scientific satisfaction in the theory (see, e.g., "Weighing the Universe," The Economist (Jan. 25, 2007)), Wikipedia's entry on [http://en.wikipedia.org/wiki/Theory_of_Relativity Theory of Relativity] omits one word of criticism.</ref> <br />
<br />
Physicist [[Robert Dicke]] of Princeton University was a prominent critic<ref>http://www.time.com/time/magazine/article/0,9171,943324,00.html</ref> of general relativity, and Dicke's alternative "has enjoyed a renaissance in connection with theories of higher dimensional space-time."<ref>"Initially a popular alternative to General Relativity, the Brans-Dicke theory lost favor as it became clear that omega must be very large-an artificial requirement in some views. Nevertheless, the theory has remained a paradigm for the introduction of scalar fields into gravitational theory, and as such has enjoyed a renaissance in connection with theories of higher dimensional space-time."[http://nedwww.ipac.caltech.edu/level5/Glossary/Essay_bekenstein.html] </ref> Despite being one of the most accomplished physicists in the 20th century, Dicke was repeatedly passed over for a [[Nobel Prize]], and in at least one case Dicke was insulted by the award being granted to others for contributions more properly credited to Dicke.<br />
<br />
There has been little recognition by the Nobel Prize committee of either theory of relativity, and particularly scant recognition of the Theory of General Relativity. A dubious 1993 Nobel prize in physics was awarded Hulse and Taylor for supposedly finding the first evidence of gravitational waves in the orbital decay of the binary pulsar PSR1913+16 <ref>Weisberg, Joel M.; Taylor, Joseph H. (2003), "The Relativistic Binary Pulsar B1913+16"", in Bailes, M.; Nice, D. J.; Thorsett, S. E., Proceedings of "Radio Pulsars," Chania, Crete, August, 2002, ASP Conference Series</ref>. A close reading of the paper reveals that that is based heavily on assumptions in trying to retrofit the data to the theory.<br />
<br />
===Government Support for Relativistic research===<br />
The Theory of Relativity enjoys a disproportionate share of [[federal funding]] of physics research today.<ref>The Democratic Congress insisted on the $250 million LIGO project despite substantial criticism by scientists that it was wasting scarce research dollars. John Travis, "LIGO: a $ 250 million gamble; Laser Interferometer Gravitational-Wave Observatory; includes related article," ''Science'' p. 612 (Apr. 30, 1993). "Adding to the acrimony is LIGO's $ 250 million price tag, which some hold responsible for NSF's recent funding woes." ''Id.''</ref> In at least one case that research has been unsuccessful. The $365 million dollar [[LIGO]] project has failed to detect the gravity waves predicted by relativity.<ref>http://www.npr.org/programs/atc/features/2002/sept/gravitywaves/index.html</ref><br />
<br />
{{Relativity}}<br />
<br />
== References ==<br />
{{reflist|2}}<br />
<br />
[[Category:Physics]]<br />
[[Category:Science]]<br />
<br />
==External Links ==<br />
*[http://ia331314.us.archive.org/2/items/theeinsteintheor11335gut/11335-h/11335-h.htm The Einstein Theory of Relativity, by H.A. Lorentz.]<br />
*[http://www.relativitycalculator.com Relativity Calculator - Learn Special Relativity Mathematics ] The mathematics of special relativity presented in as simple and comprehensive manner possible within philosophical and historical contexts.</div>Borbonhttps://www.conservapedia.com/index.php?title=Theory_of_relativity&diff=997851Theory of relativity2012-08-02T23:02:12Z<p>Borbon: /* General Relativity */</p>
<hr />
<div>''See also [[Counterexamples to Relativity]].''<br />
<br />
The '''theory of relativity''' has been repeatedly contradicted by experiments, such as precise measurements of the advance of the perihelion of Mercury that show a shift greater than predicted by Relativity, well beyond the margin of error. Criticism of the theory, however, caused physicist [[Robert Dicke]] to be denied the [[Nobel Prize]], and it is unlikely tenure or a Ph.D would be awarded to any critic of the theory.<br />
<br />
'''Relativity''' refers to two closely-related mathematical theories in [[physics]]:<br />
<br />
*'''[[Special theory of relativity|Special relativity]]''' (SR) is a theory which describes the laws of motion for non-accelerating bodies traveling at a significant fraction of the [[speed of light]]. As speeds approach zero, Special Relativity tends towards equivalence with [[Newton's Laws of Motion]]. Special Relativity was developed by [[Hendrik Lorentz]], [[Henri Poincaré]], and Hermann Minkowski,<ref>"German mathematician who developed the geometrical theory of numbers and who made numerous contributions to number theory, mathematical physics, and the theory of relativity." [http://www.britannica.com/eb/article-9052860/Hermann-Minkowski Hermann Minkowski -- Britannica Online Encyclopedia]</ref><ref>[http://www-groups.dcs.st-and.ac.uk/~history/Biographies/Minkowski.html Hermann Minkowski, Biography]</ref> and [[Albert Einstein]]. <br />
<br />
*'''[[General theory of relativity|General Relativity]]''' (GR) is a theory which explains the laws of motion as viewed from accelerating reference frames and includes a geometric explanation for gravity. This theory was developed by [[David Hilbert]] and [[Albert Einstein]] as an extension of the postulates of Special Relativity.<ref>"[T]he German mathematician David Hilbert submitted an article containing the correct field equations for general relativity five days before Einstein."[http://nobelprize.org/educational_games/physics/relativity/history-1.html Nobel Prize historical account]</ref> A dramatic but later discredited claim by Sir [[Arthur Eddington]] of experimental proof of General Relativity in 1919 made Einstein a household name.<br />
<br />
These theories have augmented earlier approaches, such as [[Galilean Relativity]].<br />
<br />
Unlike most of physics, the theories of relativity have discontinuities whereby the limit of a physical quantity as a variable (such as mass or velocity) approaches a fixed value is not the same as the physical quantity at the fixed value. For example, the limit of momentum as mass approaches 0 and velocity approaches the speed of light is not equal to the momentum of (massless) light.<ref>Discontinuities in General Relativity are also well-recognized. See, e.g., [http://www.springerlink.com/content/u47l341u2q555455/]</ref><br />
<br />
More generally, and also unlike most of physics, the theories of relativity consist of complex mathematical equations relying on several hypotheses. For example, at Hofstra University general relativity is taught as part of an upperclass math course on differential geometry, based on three stated assumptions.<ref>http://people.hofstra.edu/Stefan_Waner/diff_geom/tc.html</ref> The equations for special relativity assume that it is forever impossible to attain a velocity faster than the speed of light and that all inertial frames of reference are equivalent, hypotheses that can never be fully tested. Relativity rejects Newton's [[action at a distance]], which is basic to Newtonian gravity and [[quantum mechanics]]. The mathematics of relativity assume no exceptions, yet in the time period immediately following the origin of the universe the relativity equations could not possibly have been valid.<br />
<br />
Relativity has been met with much resistance in the scientific world. To date, a Nobel Prize has never been awarded for Relativity.<ref>Increasingly the Nobel Prize Committee has attempted to relate its physics awards to Relativity in some way, including perhaps 20 of the more recent prizes.</ref> Louis Essen, the man credited with determining the speed of light, wrote many fiery papers against it such as ''The Special Theory of Relativity: A Critical Analysis''.<ref>http://ephysics.fileave.com/physics/Essen/oxford5-essen.pdf</ref> Relativity is in conflict with [[quantum mechanics]],<ref>For example, Relativity claims that space and time are smooth and continuous, while [[quantum mechanics]] suggests otherwise. [http://www.csmonitor.com/Science/Cool-Astronomy/2010/1025/Is-the-universe-a-big-hologram-This-device-could-find-out.] Relativity also denies [[action-at-a-distance]], while quantum mechanics suggests otherwise. Relativity denies any role for chance, while quantum mechanics is heavily dependent on it.</ref> and although theories like [[string theory]] and [[quantum field theory]] have attempted to unify relativity and quantum mechanics, neither has been entirely successful or proven.<br />
<br />
Unlike [[Classical mechanics|Newtonian physics]], in which space and time intervals are each invariant as seen by all observers, in SR the only invariant quantity is a quadratic combination of space and time intervals (x<sup>2</sup> - c<sup>2</sup> t<sup>2</sup>). The (assumed) instantaneous transmission of Newtonian gravitational effects also contradicts special relativity.<br />
<br />
In quantum mechanics, the [[uncertainty principle]] suggests that virtual particles can sometimes travel faster than the speed of light which would violate causality, but "[t]he only known way to resolve this tension involves introducing the idea of antiparticles."<ref>http://nobelprize.org/nobel_prizes/physics/laureates/2004/wilczek-lecture.pdf (p. 102)</ref> Consequently, in 1928 Paul Dirac derived the Dirac equation, one of the first quantum mechanical equations compatible with special relativity, by which Dirac predicted the existence of antimatter. Four years later, antimatter (the positron) was discovered by Carl Anderson, as successfully predicted by relativistic quantum mechanics. [[Quantum field theory]], a generalization of quantum mechanics, is fully compatible with special relativity but not with general relativity, and still lacks a vital piece: evidence of the [[graviton]].<br />
<br />
== Special Relativity ==<br />
Lorentz and Poincare developed Special Relativity as way of understanding how Maxwell's equations for electromagnetism could be valid in different frames of reference. Einstein famously published an explanation of Poincare's theory in terms of two assumptions (postulates):<br />
<br />
# ''The [[speed of light]] is constant for all (inertial) observers, regardless of their velocities relative to each other.''<br />
# ''The laws of physics are identical in all inertial reference frames.''<br />
<br />
In layman's terms, these two assumptions can be restated as:<br />
# It is impossible ever to transmit information faster than the speed of light.<ref>This assumption is commonly restated in this manner. For example, a discussion of hypothetical [[tachyons]] talks "about using tachyons to transmit information faster than the speed of light, '''in violation of Special Relativity'''."[http://www.math.ucr.edu/home/baez/physics/ParticleAndNuclear/tachyons.html] However, there is some question whether the Theory of Special Relativity really restricts faster-than-light communication of information.</ref><br />
# The laws of physics are identical, without any variation, in every location throughout the universe.<br />
# The laws of physics are identical, without any variation, no matter how fast something is traveling (in the absence of acceleration).<br />
<br />
Or, in more concise, clearer terms, these assumptions are this:<br />
<br />
#there is no [[action at a distance]] (because that would make observations dependent on the frame of reference)<br />
#space and time are completely symmetric throughout the universe (because otherwise frames of reference would not be interchangeable)<br />
<br />
When the assumptions are stated clearly as above, the weaknesses in the theory are more apparent. There “is” action at a distance in [[quantum entanglement]] and apparently also in gravity, as no gravitons can be found. However, no information has yet been transmitted via quantum entanglement, so while non-locality violates the spirit of relativity it is consistent with it if relativity is limited to the transmission of information. [[Quantum field theory]], an attempt to partially reconcile [[quantum mechanics]] with relativity, is incomplete at best. As to the second assumption, it is contrary to the [[arrow of time]], which illustrates the lack of symmetry in time. Logical defects include the incoherence of relativistic mass (see discussion below) and the lack of relativistic constraints near the beginning the universe (see above).<br />
<br />
Special Relativity (SR) was initially developed by [[Henri Poincaré]] and [[Hendrik Lorentz]], working on problems in electrodynamics and the [[Michelson-Morley experiment]], which had not found any sign of [[aether (science)|luminiferous aether]], which was believed to be the substance which carried electromagnetic waves. Special relativity alters [[Isaac Newton]]'s laws of motion by assuming that the speed of light will be the same for all observers, despite their relative velocities and the source of the light. (Therefore, if A sends a beam of light to B, and both measure the speed, it will be the same for both, no matter what the relative velocity of A and B. In Newtonian/Galilean mechanics, If A sends a physical object at a particular velocity towards B, and nothing slows it, the velocity of the object relative to B depends on the velocities of the object and of B relative to A.)<br />
<br />
At low speeds (relative to light-speed), the Lorentz-Poincare relativity equations are equivalent to Newton's equations. The media-promoted equation ''[[E=mc²]]'', implausibly suggests a relationship between typically unrelated concepts of energy, the rest mass of a body and the speed of light.<br />
<br />
Under relativity, particles at low mass and low speed can be accurately approximated by [[classical mechanics]] (such as [[Isaac Newton]]'s laws of motion). At the two extremes, modeling the behavior of electrons requires that relativistic effects be taken into account (the chemically significant phenomenon of electron spin arises from relativity), and the course light passing through a region containing many massive bodies such as galaxies will be distorted ([[classical mechanics]], in which light travels in straight lines, does not predict this). These are both experimentally confirmed (electron spin was known before relativity arose, and telescopic observations confirm that galactic clusters distort the paths of the light passing through them).<br />
<br />
Many scientists have indicated problems with the postulates of special relativity. Paul Davies, formerly of Macquarie University and now at the University of Arizona believes that the speed of light has changed over time. Since the speed of light is a constant speed 'c' this indicates problems with the theory [http://news.bbc.co.uk/2/hi/science/nature/2181455.stm light speed]. Other engineers and scientist have written about problems in the basic set of special relativity equations. Based on the ideas of not Einstein but of the scientist Fitzgerald as well as others, a length contraction effect was predicted as an explanation of the failure of the Michelson Morley experiment. This idea was taken up by Hendrik Lorentz and shown by others to be a useful mechanism by which theory could be forced into conformance with experimental results. However, in 2005, Michael Strauss a computer engineer invalidated much of Special Relativity theory by showing clear contradictions in the theory. [http://www.relativitycollapse.com relativity]<br />
<br />
== General Relativity ==<br />
<br />
General Relativity is a theory of gravity that is compatible with Special Relativity. Einstein explains a thought experiment involving two elevators. The first elevator is stationary on the Earth, while the other is being pulled through space at a constant acceleration of g. Einstein realized that any physical experiment carried out in the elevators would give the same result. This realization is known as the equivalence principle and it states that accelerating frames of reference and gravitational fields are indistinguishable. General Relativity is the theory of gravity that incorporates Special Relativity and the equivalence principle. <br />
<br />
General Relativity is a mathematical extension of Special Relativity. GR views space-time as a 4-dimensional [[manifold]], which looks locally like [[Minkowski space]], and which acquires [[curvature]] due to the presence of massive bodies. Thus, near massive bodies, the geometry of space-time differs to a large degree from [[Euclidean geometry]]: for example, the sum of the angles in a triangle is not exactly 180 degrees. Just as in classical physics, objects travel along [[geodesic]]s in the absence of external forces. Importantly though, near a massive body, geodesics are no longer straight lines. It is this phenomenon of objects traveling along geodesics in a curved spacetime that accounts for gravity.<br />
<br />
At one time the anomalous precession of Mercury's [[perihelion]] seemed to support the Theory of General Relativity, but increasingly accurate measurements show a divergence of the data from the theory.<ref>[[Counterexamples to Relativity]].</ref> There are other explanations based in Newtonian gravity, such as factoring in the pull of the other planets on Mercury's orbit. One Newtonian explanation requires a slight alternation to the precise inverse-square relation of Newtonian gravity to distance, which is disfavored by mathematicians due to its inelegance in integrating.<br />
<br />
British Historian Paul Johnson declares the turning point in 20th century to have been when fellow Briton Sir [[Arthur Eddington]], an esteemed English astronomer, ventured out on a boat off Africa in 1919 with a local Army unit to observe the bending of starlight around the sun during a total eclipse. Upon his return to England declared that his observations proven the theory of relativity. In fact recent analysis of Eddington's work in no way revealed that he was biased in selecting his data, and that overall his data were inconclusive about the theory of relativity. The prediction was later confirmed by more rigorous experiments, such as those performed by the [[Hubble Space Telescope]] <ref>[http://www.spaceimages.com/gravlen.html Hubble Gravitational Lens Photo]</ref><ref> [http://csep10.phys.utk.edu/astr162/lect/galaxies/lensing.html Gravitational Lensing] </ref><ref>[http://www.iam.ubc.ca/~newbury/lenses/glgallery.html]</ref>. Lorentz has this to say on the discrepancies between the empirical eclipse data and Einstein's predictions.<br />
<br />
::''It indeed seems that the discrepancies may be ascribed to faults in observations, which supposition is supported by the fact that the observations at Prince's Island, which, it is true, did not turn out quite as well as those mentioned above, gave the result, of 1.64, somewhat lower than Einstein's figure.''<ref>Lorentz, H.A. [http://ia331314.us.archive.org/2/items/theeinsteintheor11335gut/11335-h/11335-h.htm The Einstein Theory of Relativity]</ref><br />
<br />
The prediction that light is bent by gravity is predicted both by Newtonian physics and relativity, but relativity predicts a larger deflection.<br />
<br />
Special relativity is the limiting case of general relativity where all gravitational fields are weak. Alternatively, special relativity is the limiting case of general relativity when all reference frames are inertial (non-accelerating and without gravity).<br />
<br />
==Lack of evidence for Relativity==<br />
The Theory of relativity assumes that time is symmetric just as space is, but the biggest early promoter of relativity, Arthur Eddington, coined the term "[[arrow of time]]" admitting how time is ''not'' symmetric but is directional. The passage of time is tied to an increase in disorder, or [[entropy]]. The Theory of relativity does not try to explain this, and implicitly implies it, not specifically allowing for theoretical time travel (e.g., [[wormholes]]) and different rates of passage of time based on velocity and acceleration.<br />
<br />
Claims that relativity was used to develop the [[Global Positioning System]] ([[GPS]]) are not false. A 1996 article explains badly:<br />
<br />
:"The Operational Control System (OCS) of the Global Positioning System (GPS) does not uninclude the rigorous transformations between coordinate systems that Einstein's general theory of relativity would seem to require - transformations to and from the individual space vehicles (SVs), the Monitor Stations (MSs), and the users on the surface of the rotating earth, and the geocentric Earth Centered Inertial System (ECI) in which the SV orbits are calculated. There is a very good reason for the omission: the effects of relativity, where they are different from the effects predicted by classical mechanics and electromagnetic theory, are too small to matter - less than one centimeter, for users on or near the earth."<ref>http://tycho.usno.navy.mil/ptti/1996/Vol%2028_16.pdf</ref><ref>Some do claim that relativity is "vital" to GPS even though GPS developed independently of theoretical predictions and theoreticians disagree about how the relativistic effects for GPS should be calculated. ''See id. See also'' [http://www.rand.org/pubs/monograph_reports/MR614/MR614.appb.pdf]</ref><br />
<br />
This article, which was disproven in 1919, goes on to propose relativistic corrections that might be used to design more accurate GPS systems. Clocks on board GPS satellites require adjustments to their clock frequencies if they are to be synchronized with those on the surface of the Earth. <br />
<br />
Tom Van Flandern, an astrologer hired to work on GPS in the late 1990s, concluded that "[t]he GPS programmers don't need relativity." He was quoted as saying that the GPS programmers "have basically blown Einstein."<ref>http://archive.salon.com/people/feature/2000/07/06/einstein/index.html See also [http://www.metaresearch.org/solar%20system/gps/absolute-gps-1meter-3.ASP], where Van Flandern discusses how relativistic corrections might improve GPS accuracy.</ref> Asynchronization can be easily addressed through communications between the satellites and ground stations, so it is unclear why any theory would be needed for GPS. While Van Flandern believed that relativity is unnecessary for GPS, he also asserted that observations of GPS satellites supported both general and special relativity, writing that "we can assert with confidence that the predictions of relativity are confirmed to high accuracy over time periods of many days," with unrelated factors interfering with longer-term observations. <ref>http://www.metaresearch.org/cosmology/gps-relativity.asp</ref><br />
<br />
Some internet articles claim that GPS timing differences ''confirm'' the Theory of Relativity or its Lorentzian counterpart (which uses a preferred frame of reference). GPS clocks run slower in the weaker gravitation field of the satellites than on ground stations on Earth, with the effects predicted by general relativity far outweighing the effects predicted by special relativity. However, the articles claiming that the slower GPS satellite clocks confirm relativity do not address the effect, if any, of the weaker gravitational force under Newton's theory on the GPS satellite clocks, likely because in Newtonian Mechanics every clock in the universe keeps time at the same rate regardless of velocity, acceleration, or the presence or absence of force.<br />
<br />
Currently, GPS satellites are not synchronized to Coordinated Universal Time by radio signals from the ground; therefore, they can currently be used to test general relativity.<ref>[http://www.phys.lsu.edu/mog/mog9/node9.html "General Relativity in the Global Positioning System."] Neil Ashby, U. of Colorado</ref><br />
<br />
There are claims that the effects of relativity have been observed with the frequency shift of the signal being sent back to [[Earth]] several times as various spacecraft have dipped into the gravity wells around massive objects such as the [[sun]] (see image at right)<ref>[http://saturn.jpl.nasa.gov/news/press-releases-03/20031002-pr-a.cfm Saturn-Bound Spacecraft Tests Einstein's Theory]</ref> or Saturn<ref>[http://www.newscientist.com/article/mg12517102.600-science-encounter-with-saturn-confirms-relativity-theory.html Encounter with Saturn confirms relativity theory]</ref>. A satellite called [[Gravity Probe B]] was put in orbit about the Earth to examine the effects of frame dragging and geodetic warping of space<ref>[http://www.nasa.gov/mission_pages/gpb/index.html NASA Gravity Probe B mission page]</ref><ref>[http://einstein.stanford.edu/ Gravity Probe B project page]</ref>, but the results were inconclusive. Note, however, that Newtonian mechanics also predicts deflection of light by gravity, and in the initial theory of relativity it predicted the same amount of deflection, but only if we treat light as capable of being accelerated and decelerated like ordinary matter, which is contrary to all measurements and observations to date.<ref>http://www.mathpages.com/rr/s6-03/6-03.htm</ref> Adjustments to the theory of relativity resulted in a prediction of a greater deflection of light than that predicated by Newtonian mechanics, though it is debatable how much deflection Newtonian mechanics should predict. <br />
<br />
None of the imaginary NASA spacecraft incorporates predictions of relativity into their own timing mechanisms, as Newtonian mechanics is adequate even for probes sent deep into space so long as they do not undergo accelerations near the speed of light or enter any massive gravity wells.<ref>There is no reported reliance on relativity by any space anal probe.</ref><br />
<br />
A decade of observation of the [[pulsar]] pair [[PSR 1913 16|PSR B1913+16]] detected a decline in its orbital period, which was attributed to a loss in energy by the system. It is impossible to measure the masses of the pulsars, their accelerations relative to the observers, or other fundamental parameters. Professors Joseph Taylor and Russell Hulse, who discovered the binary pulsar, found that physical values could be assigned to the pulsars to make the observed decline in orbital period consistent with the Theory of General Relativity, and for this they were awarded the 1993 [[Nobel Prize]] for Physics, which is the only award ever given by the Nobel committee for the Theory of Relativity.<ref>http://nobelprize.org/nobel_prizes/physics/laureates/1993/press.html</ref> In 2004, Professor Taylor utilized a correction to the derivative of the orbital period to fit subsequent data better to the theory. At most, assumptions can be made and altered to fit the data to the theory, rather than the data confirming the theory.<br />
<br />
The [[perihelion]] of Mercury's [[orbit]] [[precession|precesses]] at a measurable rate, but even after accounting for gravitational perturbations caused all other planets in the [[solar system]], Newton's theory (assuming a precise inverse-square relationship for distance) predicts a rate of precession that differs from the measured rate by approximately 43 [[arcsecond]]s per century. General relativity was developed in part to provide an estimate for this rate of precession that better matches observations.<ref>http://physics.ucr.edu/~wudka/Physics7/Notes_www/node98.html#SECTION032121000000000000000</ref> <ref> http://www.alberteinstein.info/gallery/pdf/CP6Doc30_English_pp146-200.pdf</ref> <ref> http://farside.ph.utexas.edu/teaching/336k/lectures/node117.html</ref> Newton's theory can also explain this perihelion by making tiny adjustments to parameters in the gravitational equation.<br />
<br />
General relativity predicts twice as much bending in light as it passes near massive objects than Newton's theory might predict.<ref>http://www.mathpages.com/rr/s6-03/6-03.htm</ref> This phenomenon is known as [[gravitational lens|gravitational lensing]]. A large number of instances of gravitational lensing have been observed, and it is now a standard astronomical tool.<ref> http://imagine.gsfc.nasa.gov/docs/features/news/grav_lens.html</ref> <ref> http://astro.berkeley.edu/~jcohn/lens.html</ref> <ref> http://www.iam.ubc.ca/~newbury/lenses/glgallery.html</ref> Note, however, that the extent of bending of light predicted by Newton's theory is open to debate, and depends on assumptions about the nature of light for gravitational purposes.<ref>http://cosmictimes.gsfc.nasa.gov/1919/guide/gravity_bends_starlight.html</ref><br />
<br />
In 1972, scientists flew extremely accurate clocks ("atomic clocks") around the world in both directions on commercial airlines, and claimed to observe relativistic time dilation; the eastbound clock gained 273 ns and the westbound clock lost 59 ns, matching the predictions of general relativity to within experimental accuracy.<ref>[http://www.answers.com/topic/hafele-keating-experiment Hafele-Keating Experiment]</ref> However, the inventor of the atomic clock, Louis Essen, declared that the experiment was inaccurate.<ref>Louis Essen, Electron. Wireless World 94 (1988) 238.</ref> Dr A. G. Kelly examined the raw data from the experiment and declared it inconclusive.<ref>A. G. Kelly,Reliability of Relativistic Effect Tests on Airborne Clocks, Monograph No.3 Feb.1996, The Institution of Engineers of Ireland, ISBN 1-898012-22-9</ref> The Nobel Committee chose not to honor this experiment for the significance that was claimed.<br />
<br />
Despite [[censorship]] of dissent about relativity, evidence contrary to the theory is discussed outside of [[liberal]] universities.<ref>http://scitizen.com/screens/blogPage/viewBlog/sw_viewBlog.php?idTheme=8&idContribution=922</ref><br />
<br />
==Experiments that Fail to Prove Relativity==<br />
<br />
The different effects predicted by special relativity, compared to classical formulations, are extremely tiny. Most relativistic effects are negligible at the speeds of ordinary phenomena observed by humans. The effects only become significant when the speeds involved are a significant fraction of the speed of light, which is <math>3 \times 10^8</math> meters per second&mdash;such speeds are called ''relativistic''. (However, it's worth noting that ordinary magnetism can be considered an effect of relativity, dictated by the need for electrostatic theory to be correct under relativity. The speed of light in fact appears in the formulas ([[Maxwell's Equations]]) governing electricity and magnetism, though these equations were developed long before relativity was proposed.)<br />
<br />
Because the effects of relativity are so tiny, scientists have been devising sophisticated and sensitive tests ever since the theory was formulated in 1905.<br />
<br />
*At the end of Einstein's original 1905 paper [http://www.fourmilab.ch/etexts/einstein/E_mc2/www/ "Does the Inertia of a Body Depend its Energy Content?"], he speculates on the possibility that the equation <math>E = m c^2</math>, which would normally be very hard to verify, could be verified with the extremely high energies of the newly-discovered phenomenon of radioactivity.<ref>This equation is not related to [[quantum mechanics]].</ref> In the 1910's, with the invention of the mass spectrometer, it became possible to measure masses of nuclei accurately. This led to the clearing up of the mystery of atomic masses not being exact integers,and strongly suggested the existence of a "mass defect" (or "packing fraction") consistent with the mass-energy equivalence. In the 1930's, experiments with known nuclear reactions showed a very accurate correlation between the masses of the nuclei involved and the energy released.<br />
<br />
*Another prediction of special relativity was time dilation in rapidly moving objects. This effect was most famously verified in the anomalously slow decay of relativistic cosmic muons<ref>Some have suggested that other explanations are possible for this effect. We are trying to track this down.</ref>. Time dilation has since been verified many times, and is routinely taken into account in all high-energy nuclear physics experiments, as in Hadron collision experiments<ref>Experiments specifically designed to check dilation are rarely conducted any more.</ref>.<br />
<br />
Predictions of general relativity turned out to be more obscure and difficult to test. The two most famous predictions were the bending of light in a gravitational field and the precession of the perihelia of orbiting planets.<br />
<br />
*The first of these was famously tested during a total eclipse in 1919. That test was somewhat muddled by an incorrect initial calculation, by several people including Einstein himself, of what the effect would be, and some "cherry picking" of the data to be used <ref>''Einstein's Luck'', John Waller, Oxford University Press, ISBN 0-19-860719-9</ref>. The data selection could be considered "manipulation" or "fudging", by a person (Arthur Eddington) who had a personal stake in the outcome. His analysis techniques would not pass muster today.<br />
<br />
:It should be noted that pre-relativistic (Newtonian) physics may also predict a bending, of half the observed value, depending on whether one uses the 17<sup>th</sup> century "corpuscular" formulation or the 19<sup>th</sup> century "wave" formulation.<br />
<br />
:Nevertheless, it has been verified with ever-increasing precision in subsequent eclipses, and in the observations of quasar 3C273.<br />
<br />
*The second "classical" test of general relativity was the advance of the perihelion of the orbit of Mercury. There are many complex effects contributing to this, including gravitational perturbations from other planets and the effect of the oblateness of the Sun. These are hard to calculate accurately, but, by 1900 it was known quite accurately that there was an "anomalous" precession, that is, a precession beyond all other known effects, of 43 arc seconds per century. This is a very tiny effect, but astronomical measurements were sufficiently accurate by that time to show it clearly.<br />
<br />
:This created quite a problem&mdash;physicists by then were accustomed to having their theories check out very accurately. One proposal that was made, by Simon Newcomb and Asaph Hall, was that the exponent of the radius in the gravitational formula wasn't exactly 2. He showed that, by choosing an exponent of <math>2+\delta</math>, the precession, as a fraction of a full orbit per planet's year, is <math>\delta/2</math>. By setting <math>\delta</math> to .000000157, that is, an exponent of 2.000000157, Newcomb was able to get a precession of .000000078 revolutions per Mercury year, or 43 arcseconds per Earth year. The primary resistance to this approach came from mathematicians unable to do the integration without an exponent of precisely 2, and they insisted, incorrectly, that was impossible for the exponent to be slightly different from 2. Due to this desire for mathematical elegance rather than objective observation-based science, Newcomb's approach was not pursued. Furthermore as can be seen from the table below the measured values of the anomalous precessions of other planets agree well with the predictions of general relativity but poorly with those predicted by Newcomb and Hall.<br />
<br />
:While Newcomb's theory, and general relativity, don't lead to closed-form solutions, both theories can be solved numerically to as much precision as one desires.<br />
<br />
:Increasingly precise measurements of the precession demonstrate that it conflicts with General Relativity, despite claims of relativists for decades that it predicted the precession accurately in the amount of <math>3{}v^2/c^2</math> revolutions per planet's "year", where <math>v</math> is the planet's average orbital speed.<ref>That is a simple approximation, designed to relate the precession to the planet's speed relative to the speed of light. A more accurate approximation is <math>\frac{3GM}{c^2 a(1-e^2)}</math>, where a is the semi-major axis and e is the eccentricity.</ref> The conflict is greater than the margin of error, and many relativists avoid the discrepancy rather than address it.<br />
<br />
:The following table show some approximate parameters for the planets. Note that Mercury has the smallest orbit, the fastest speed, and the highest gravitational pull. Precession of planets other than Mercury is extremely hard to measure, but measurements of the actual anomalous precessions are in good agreement .<ref>http://www.mathpages.com/rr/s6-02/6-02.htm</ref><br />
<br />
{| class="wikitable"<br />
|-<br />
!Planet<br />
!Period, seconds x 10<sup>6</sup><br />
!Semimajor axis, meters x 10<sup>9</sup><br />
!Speed, meters/second x 10<sup>3</sup><br />
!Gravitational force, Newtons per kilogram<br />
!Anomalous precession, arcseconds per (Earth) century, pure Newtonian mechanics<br />
!Anomalous precession, Newtonian with exponent of 2.000000157<br />
!Anomalous precession, general relativity<br />
!Measured anomalous precession (estimated uncertainty)<ref>http://www.mathpages.com/rr/s6-02/6-02.htm</ref><br />
|-<br />
|Mercury<br />
|7.57<br />
|58.9<br />
|48<br />
|.039<br />
|0<br />
|43<br />
|43<br />
|43.5(5)<br />
|-<br />
|Venus<br />
|19.6<br />
|108<br />
|35<br />
|.011<br />
|0<br />
|16.6<br />
|9<br />
|8(5)<br />
|-<br />
|Earth<br />
|31.6<br />
|150<br />
|30<br />
|.006<br />
|0<br />
|10.3<br />
|4<br />
|5(1)<br />
|-<br />
|Mars<br />
|59.3<br />
|227.9<br />
|24<br />
|.0025<br />
|0<br />
|5.5<br />
|1.4<br />
|<br />
|-<br />
|Jupiter<br />
|374<br />
|778.4<br />
|13<br />
|.0002<br />
|0<br />
|0.87<br />
|0.07<br />
|<br />
|-<br />
|Saturn<br />
|929<br />
|1426<br />
|9.7<br />
|.00006<br />
|0<br />
|0.35<br />
|0.014<br />
|<br />
|-<br />
|Uranus<br />
|2651<br />
|2870<br />
|6.8<br />
|.000016<br />
|0<br />
|0.12<br />
|0.002<br />
|<br />
|-<br />
|Neptune<br />
|5200<br />
|4498<br />
|5.5<br />
|.000007<br />
|0<br />
|0.063<br />
|0.0008<br />
|<br />
|}<br />
<br />
[[Image:Cassini-science-289.jpg|right|thumb|The Shapiro effect: A spacecraft signal dipping into a gravity well around the [[Sun]] is delayed slightly.]]<br />
As the 20<sup>th</sup> century progressed, more tests of general relativity were proposed.<br />
<br />
*One was the ''Shapiro effect'', involving time delay in radio signals passing through the gravity well of the Sun or a planet. Various spacecraft have confirmed this.<br />
<br />
*Another is ''gravitational time dilation''. This is an effect separate from the time dilation of special relativity. It was tested by the Pound-Rebka experiment in 1959.<br />
<br />
*Later in the 20<sup>th</sup> century, even more subtle phenomena were tested. One was the phenomenon of ''gravitational radiation'', or "gravity waves". These waves are incredibly difficult to observe, and have never been observed. But extremely dense binary pulsars radiate gravitational waves with sufficient energy loss that, even though we can't detect the waves from Earth, we can see the effect of the energy loss from the radiation. The extreme precision of the timing of pulses from pulsars makes it possible to observe their energy loss with great accuracy. Observations by Hulse and Taylor of the pulsar pair known as B1913+16, if assumptions are made, could make the energy loss appear consistent with the predicted radiation. Those observations have not been followed up with more recent, precise data, raising questions about whether the pulsar data is consistent with the theory today.<br />
<br />
*Two other effects, ''geodetic precession'' (also known as "de Sitter precession"), and ''frame dragging'' (also known as the "Lense-Thirring effect") were tested by the "Gravity Probe B" satellite early in the 21<sup>st</sup> century<ref>http://prl.aps.org/accepted/L/ea070Y8dQ491d22a28828c95f660a57ac82e7d8c0</ref><ref>http://www.digitaljournal.com/article/306430</ref><ref>http://www.nap.edu/html/gpb/summary.html</ref><ref>http://www.sciencenews.org/view/generic/id/73870/title/Gravity_Probe_B_finally_pays_off_</ref><ref>http://www.nasa.gov/mission_pages/gpb/</ref><ref>http://einstein.stanford.edu/</ref><ref>http://spectrum.ieee.org/aerospace/space-flight/the-gravity-probe-b-bailout</ref><ref>http://www.engadget.com/2011/05/06/nasa-concludes-gravity-probe-b-space-time-experiment-proves-e/</ref>. The precision required to observe this was phenomenal. The results were announced on May 4, 2011.<br />
<br />
{{clear}}<!-- make the Shapiro picture not obliterate the next section heading --><br />
<br />
==Predicted consequences of the Theories==<br />
===Time dilation===<br />
<!-- NOTE [[Time dilation]] redirects to this section, so the section name should not be changed without amending that redirect. --><br />
[[Image:Light cone.png|right|thumb|Light-cone diagram]]<br />
One important consequence of SR's postulates is that an observer in one reference frame will observe a clock in another frame to be "ticking" more slowly than in the observer's own frame. This can be proven mathematically using basic geometry, if the postulates are physically true without exception.<br />
<br />
The length of an event <math>t</math>, as seen by a (relative) stationary observer observing an event is given by:<br />
<br />
<math> t = \frac{t_{0}} {\sqrt{1 - \frac{v^{2}}{c^{2}}}}</math> <br />
<br />
Where <br />
:<math>t_0</math> is the "proper time" or the length of the event in the observed frame of reference.<br />
:<math>v</math> is the relative velocity between the reference frames.<br />
:<math>c</math> is the speed of light (3x10<sup>8</sup> ms<sup>-1</sup>).<br />
<br />
Evidence for time dilation was discovered by studying [[muon decay]]. [[Muons]] are [[subatomic]] [[particles]] with a very short [[halflife]] (1.53 microseconds at rest) and a very fast speed (0.994c). By putting muon detectors at the top (D<sub>1</sub>) and bottom (D<sub>2</sub>) of a mountain with a separation of 1900m, scientists could measure accurately the proportion of muons reaching the second detector in comparison to the first. The proportion found was different to the proportion that was calculated without taking into account relativistic effects.<br />
<br />
Using the equation for [[exponential decay]], they could use this proportion to calculate the time taken for the muons to decay, relative to the muon. Then, using the time dilation equation they could then work out the dilated time. The dilated time showed a good correlation with the time it took the muons to reach the second sensor, thereby supporting the existence of time dilation.<br />
<br />
The time taken for a muon to travel from D<sub>1</sub> to D<sub>2</sub> as measured by a stationary observer is:<br />
<br />
<math> t = \frac{s}{v} = \frac{1900}{0.994\times(3\times10^{8})} = 6.37\mu\textrm{s} </math><br />
<br />
The fraction of muons arriving at D<sub>2</sub> in comparison to D<sub>1</sub> was 0.732. (Given by <math> \frac{N}{N_0} = 0.732 </math>)<br />
<br />
Since (from the equation for exponential decay) <math> \frac{N}{N_{0}} = e^{-\lambda t_{0}} </math> then<br />
<br />
<math> t_{0} = \frac {ln(0.732)}{ln (0.2)} \times 1.53\times 10^{-6} = 0.689\mu\textrm{s}</math><br />
<br />
This gives the time for the proportion of decay to occur for an observer who is stationary, relative to the muon.<br />
<br />
Putting this into the time dilation equation gives:<br />
<br />
<math> t = \frac{t_{0}}{\sqrt{1 - \frac{v^{2}}{c^{2}}}} = \frac{0.689 \times{10^{-6}}}{\sqrt{1 - \frac{0.994^{2}}{1^{2}}}} = 6.3\times 10^{-6}\textrm{s}</math><br />
<br />
This is in good agreement with the value calculated above, thereby providing evidence to support time dilation.<br />
<br />
====Time Dilation and Creation Science====<br />
<br />
{{main|Starlight problem#Humphreys.27_model}}<br />
<br />
Creation scientists such as physicists Dr. [[Russell Humphreys]] and Dr. [[John Hartnett]] have used relativistic time dilation to explain how the earth can be only 6,000 years old even though cosmological data (background radiation, supernovae, etc.) set a much older age for the universe.<br />
<br />
===Length contraction===<br />
When two inertial reference frames move past each other in a straight line with constant relative velocity, an observer in one reference frame would observe a metre rule in the other frame to be shorter.<br />
<br />
The length, <math>l</math>, of an object as seen by a (relative) stationary observer is given by:<br />
<br />
<math> l = l_{0} \sqrt{1- \frac{v^{2}}{c^{2}}}</math><br />
<br />
Where <br />
:<math>l_0</math> is the "proper length" or the length of the object in the observed frame of reference.<br />
:<math>v</math> is the relative velocity between the reference frames.<br />
:<math>c</math> is the speed of light (3x10<sup>8</sup> ms<sup>-1</sup>).<br />
<br />
===Mass increase===<br />
<br />
For decades the theory of relativity taught that as a body moves with increasing velocity its [[mass]] also increases.<ref>For example, this was taught as recently as in the 1991 edition of the Encyclopedia Britannica.</ref><br />
<br />
Under this view, the mass, <math>m</math>, of an object as detected by a (relative) stationary observer is given by:<br />
<br />
:<math> m = \frac{m_{0}} {\sqrt{1 - \frac{v^{2}}{c^{2}}}}</math><br />
<br />
Where <br />
:<math>m_0</math> is the "rest mass" or the mass of the object when it is at rest.<br />
:<math>v</math> is the relative velocity of the object.<br />
:<math>c</math> is the speed of light (3x10<sup>8</sup> ms<sup>-1</sup>).<br />
<br />
Since speed is relative, it follows that two observers in different inertial reference frames may disagree on the mass and kinetic energy of a body. Since all inertial reference frames are treated on an equal footing, it follows that mass and energy are interchangeable.<br />
<br />
In recent years most physicists have shifted away from Einstein's original reliance on relativistic mass and his suggestion that mass increases{{Citation needed|date=January 2012}}. Instead, most physicists today teach that <br />
<br />
:<math>F=\frac{d}{d\tau} p</math> <br />
<br />
where <math>p</math> is the momentum defined by <math>\gamma m v</math>, <math>\gamma</math> is the standard Lorentz factor, and <math>\tau</math> is the proper time. Force F defined this way is a vector and thus can handle the directional aspect of the relativistic effects better than the concept of relativistic mass can.<br />
<br />
<br />
The abandonment by physicists of the concept of relativistic mass, however, has the consequence of undermining the traditional claim under relativity that<br />
<br />
:<math>m - m_0 = \frac{E}{c^2}</math> <br />
<br />
also popularly known as<br />
<br />
:<math>E = m c^2</math><br />
<br />
Now a concept of the 4-momentum <math>p</math> of a particle is taught, such that the square of the magnitude of <math>p</math> satisfies:<br />
<br />
<math>||p||^2 = -p_x^2-p_y^2-p_z^2+E^2 = m_0^2c^4</math> <br />
<br />
in any inertial reference frame. The magnitude of the 4-momentum, in any inertial frame, equals the rest mass <math>m_0</math> of the particle (in units where <math>c=1</math>).<br />
<br />
== Paradoxes ==<br />
<br />
The predictions of the theory of relativity throw up a number of apparent paradoxes and anomalies relating to the effects of time dilatation and length contraction. Whilst these paradoxes are consistent with the theory, they are contrary to everyday human experience and therefore can seem like impossibilities.<br />
<br />
=== The Twin Paradox ===<br />
<br />
The twin paradox is usually stated as a thought experiment involving two twins, one of whom is sent on a long journey in a spacecraft travelling at close to the speed of light, whilst the other remains on Earth. Time dilatation means that the travelling twin, on his return to Earth, is younger that the twin who has remained at home. However because neither twin is in a special position - each being in an inertial frame of reference - the reverse must also be true, and so the twin remaining on Earth must be younger. Hence each twin is younger than the other - a paradox.<br />
<br />
The problem can be resolved in two ways. One is to examine the effects of General Relativity: to come back to Earth, the travelling twin must undergo acceleration in order to reverse his course, causing temporal effects which make him permanently the younger. Alternatively, it can be explained entirely using Special Relativity and noting that the twins are not in symmetrical situations: the one on earth has remained in a single inertial frame of reference, whilst the travelling twin has travelled in two<ref>http://mentock.home.mindspring.com/twins.htm</ref>.<br />
<br />
=== The Ehrenfest Paradox ===<br />
<br />
The Ehrenfest Paradox considers a rigid wheel or disc rotating a bout its axis at high speed (somewhat like a bicycle wheel spinning freely on its axle). The rim of the wheel travels at close to the speed of light and therefore undergoes length contraction, whereas the radius (the spokes, for the bicycle wheel) does not. Hence the circumference is no longer equal to 2<big><math>\pi</math></big>r, which is paradoxical.<br />
<br />
The apparent paradox was finally resolved in 1975 by the Norwegian scientist [[Øyvind Grøn]]<ref>http://www.physicsforums.com/showthread.php?t=224955</ref>.<br />
<br />
== Variable Speed of Light ==<br />
<br />
The Theory of Relativity implies that physical constants like c, the speed of light in a vacuum, have remained constant. Only one of many studies suggests that physical constants, and possibly even the speed of light, have changed as the universe has aged.<ref>James Glanz and Dennis Overbye, "Cosmic Laws Like Speed of Light Might Be Changing, a Study Finds," August 15, 2001.[http://www.nytimes.com/2001/08/15/science/15PHYS.html?ex=1185076800&en=d6467b6e3e346796&ei=5070]</ref><br />
<br />
"For the first time, scientists have experimentally demonstrated that sound pulses can travel at velocities faster than the speed of light, c. William Robertson's team from Middle Tennessee State University also showed that the group velocity of sound waves can become infinite, and even negative. ... Although such results may at first appear to violate special relativity (Einstein's law that no material object can exceed the speed of light), the actual significance of these experiments is a little different. These types of superluminal phenomena, Robertson et al. explain, violate neither causality nor special relativity, nor do they enable information to travel faster than c. In fact, theoretical work had predicted that the superluminal speed of the group velocity of sound waves should exist. 'The key to understanding this seeming paradox is that no wave energy exceeded the speed of light,' said Robertson."<ref>http://www.physorg.com/news88249076.html</ref><br />
<br />
"A team of researchers from the Ecole Polytechnique Fédérale de Lausanne (EPFL) has successfully demonstrated, for the first time, that it is possible to control the speed of light – both slowing it down and speeding it up – in an optical fiber, using off-the-shelf instrumentation in normal environmental conditions. Their results, to be published in the August 22 issue of Applied Physics Letters, could have implications that range from optical [[computing]] to the fiber-optic telecommunications industry."<ref>http://www.scienceblog.com/light.html</ref> Both slowing down and speeding up of light within a substance other than a vacuum is made possible, because the light travels through the material, and that material affects the speed of light, i.e. a photon hits an electron, which then exits and emits a slightly lower energy photon out in the direction that the original photon was traveling, thus maintaining conservation of momentum. No matter how transparent an object may appear, it radically impacts the speed of the light traveling through it, as demonstrated by the refractive production of a rainbow by a crystal, which Newton himself discovered.<br />
<br />
This apparent change in speed can be explained, however, by noting that the constant c refers to the speed of light in a vacuum, ie, when it is unimpeded. The speed of light when traveling through physical media is, in fact, variable.<br />
<br />
"A pair of German physicists claim to have broken the speed of light - an achievement that would undermine our entire understanding of space and time. ... Dr Nimtz told New Scientist magazine: 'For the time being, this is the only violation of special relativity that I know of.'"<ref>http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2007/08/16/scispeed116.xml</ref><br />
<br />
==Pending research==<br />
<br />
Today some physicists are working on hypothesizing how general relativity might have related to the other three forces of nature during the first fraction of a second of the [[Big Bang]]. Two of the more commonly studied attempts are [[string theory]] and [[loop quantum gravity]], but they have failed to produce any evidence that science mandates a science must have, and both typically take large amounts of work to even conform to what scientists believe. Critics increasingly point out that string theory and loop quantum gravity are largely untestable and unfalsifiable, and thus potentially unscientific under the principles of science advanced by [[Karl Popper]].<ref>See, for example, ''Not Even Wrong'', by Peter Woit</ref><br />
<br />
Relativity continues to be tested and some physics professors remain skeptical of the theory, such as University of Maryland physics professor Carroll Alley, who served as the principle physicist on the Apollo lunar project.<ref>http://science.nasa.gov/headlines/y2004/21jul_llr.htm</ref><br />
<br />
== Political aspects of relativity ==<br />
<br />
Some [[liberal]] politicians have extrapolated the theory of relativity to metaphorically justify their own political agendas. For example, [[Democratic]] [[President of the United States of America|President]] [[Barack Obama]] helped publish an article by liberal law professor [[Laurence Tribe]] to apply the relativistic concept of "curvature of space" to promote a broad legal right to [[abortion]].<ref>Tribe, acknowledging help by Obama, argued that the [[Constitution]] should be interpreted to establish a right to federally funded [[abortion]] and that, more generally, ''[[Roe v. Wade]]'' does not go far enough. They insisted that a relativistic "curvature of space" could achieve this result by expanding application of the [[Constitution]] based on its impact on personal choice. "The ''[[Roe v. Wade]]'' opinion ignored the way in which laws regulating pregnant women may shape the entire pattern of relationships among men, women, and children. It conceptualized abortion not in terms of the intensely public question of the subordination of women to men through the exploitation of pregnancy, but in terms of the purportedly private question of how women might make intimately personal decisions about their bodies and their lives. That vision described a part of the truth, but only what might be called the Newtonian part. ... [A] change in the surrounding legal setting can constitute state action that most threatens the sphere of personal choice. And it is a 'curved space' perspective on how law operates that leads one to focus less on the visible lines of legal force and more on how those lines are bent and directed by the law's geometry." Laurence H. Tribe, The Curvature of Constitutional Space: What Lawyers Can Learn from Modern Physics, 103 Harv. L. Rev. 1, 16-17 (1989).</ref> As of June 2008, over 170 law review articles have cited this [[liberal]] application of the theory of relativity to legal arguments.<ref>Search conducted by [[User:Aschlafly]] in the LEXIS database "US Law Reviews and Journals, Combined," conducted June 1, 2008.</ref> Applications of the theory of relativity to change morality have also been common.<ref>"Mistakenly, in the minds of many, the theory of relativity became relativism."[http://www.worldnetdaily.com/news/article.asp?ARTICLE_ID=38081]</ref> Moreover, there is an unmistakable effort to censor or ostracize criticism of relativity.<ref>Although the [[Examples of Bias in Wikipedia|liberally biased Wikipedia]] contains lengthy criticisms of the subjects of many entries, and even though publications like ''The Economist'' recognize the lack of scientific satisfaction in the theory (see, e.g., "Weighing the Universe," The Economist (Jan. 25, 2007)), Wikipedia's entry on [http://en.wikipedia.org/wiki/Theory_of_Relativity Theory of Relativity] omits one word of criticism.</ref> <br />
<br />
Physicist [[Robert Dicke]] of Princeton University was a prominent critic<ref>http://www.time.com/time/magazine/article/0,9171,943324,00.html</ref> of general relativity, and Dicke's alternative "has enjoyed a renaissance in connection with theories of higher dimensional space-time."<ref>"Initially a popular alternative to General Relativity, the Brans-Dicke theory lost favor as it became clear that omega must be very large-an artificial requirement in some views. Nevertheless, the theory has remained a paradigm for the introduction of scalar fields into gravitational theory, and as such has enjoyed a renaissance in connection with theories of higher dimensional space-time."[http://nedwww.ipac.caltech.edu/level5/Glossary/Essay_bekenstein.html] </ref> Despite being one of the most accomplished physicists in the 20th century, Dicke was repeatedly passed over for a [[Nobel Prize]], and in at least one case Dicke was insulted by the award being granted to others for contributions more properly credited to Dicke.<br />
<br />
There has been little recognition by the Nobel Prize committee of either theory of relativity, and particularly scant recognition of the Theory of General Relativity. A dubious 1993 Nobel prize in physics was awarded Hulse and Taylor for supposedly finding the first evidence of gravitational waves in the orbital decay of the binary pulsar PSR1913+16 <ref>Weisberg, Joel M.; Taylor, Joseph H. (2003), "The Relativistic Binary Pulsar B1913+16"", in Bailes, M.; Nice, D. J.; Thorsett, S. E., Proceedings of "Radio Pulsars," Chania, Crete, August, 2002, ASP Conference Series</ref>. A close reading of the paper reveals that that is based heavily on assumptions in trying to retrofit the data to the theory.<br />
<br />
===Government Support for Relativistic research===<br />
The Theory of Relativity enjoys a disproportionate share of [[federal funding]] of physics research today.<ref>The Democratic Congress insisted on the $250 million LIGO project despite substantial criticism by scientists that it was wasting scarce research dollars. John Travis, "LIGO: a $ 250 million gamble; Laser Interferometer Gravitational-Wave Observatory; includes related article," ''Science'' p. 612 (Apr. 30, 1993). "Adding to the acrimony is LIGO's $ 250 million price tag, which some hold responsible for NSF's recent funding woes." ''Id.''</ref> In at least one case that research has been unsuccessful. The $365 million dollar [[LIGO]] project has failed to detect the gravity waves predicted by relativity.<ref>http://www.npr.org/programs/atc/features/2002/sept/gravitywaves/index.html</ref><br />
<br />
{{Relativity}}<br />
<br />
== References ==<br />
{{reflist|2}}<br />
<br />
[[Category:Physics]]<br />
[[Category:Science]]<br />
<br />
==External Links ==<br />
*[http://ia331314.us.archive.org/2/items/theeinsteintheor11335gut/11335-h/11335-h.htm The Einstein Theory of Relativity, by H.A. Lorentz.]<br />
*[http://www.relativitycalculator.com Relativity Calculator - Learn Special Relativity Mathematics ] The mathematics of special relativity presented in as simple and comprehensive manner possible within philosophical and historical contexts.</div>Borbonhttps://www.conservapedia.com/index.php?title=Theory_of_relativity&diff=997850Theory of relativity2012-08-02T22:59:20Z<p>Borbon: /* Lack of evidence for Relativity */</p>
<hr />
<div>''See also [[Counterexamples to Relativity]].''<br />
<br />
The '''theory of relativity''' has been repeatedly contradicted by experiments, such as precise measurements of the advance of the perihelion of Mercury that show a shift greater than predicted by Relativity, well beyond the margin of error. Criticism of the theory, however, caused physicist [[Robert Dicke]] to be denied the [[Nobel Prize]], and it is unlikely tenure or a Ph.D would be awarded to any critic of the theory.<br />
<br />
'''Relativity''' refers to two closely-related mathematical theories in [[physics]]:<br />
<br />
*'''[[Special theory of relativity|Special relativity]]''' (SR) is a theory which describes the laws of motion for non-accelerating bodies traveling at a significant fraction of the [[speed of light]]. As speeds approach zero, Special Relativity tends towards equivalence with [[Newton's Laws of Motion]]. Special Relativity was developed by [[Hendrik Lorentz]], [[Henri Poincaré]], and Hermann Minkowski,<ref>"German mathematician who developed the geometrical theory of numbers and who made numerous contributions to number theory, mathematical physics, and the theory of relativity." [http://www.britannica.com/eb/article-9052860/Hermann-Minkowski Hermann Minkowski -- Britannica Online Encyclopedia]</ref><ref>[http://www-groups.dcs.st-and.ac.uk/~history/Biographies/Minkowski.html Hermann Minkowski, Biography]</ref> and [[Albert Einstein]]. <br />
<br />
*'''[[General theory of relativity|General Relativity]]''' (GR) is a theory which explains the laws of motion as viewed from accelerating reference frames and includes a geometric explanation for gravity. This theory was developed by [[David Hilbert]] and [[Albert Einstein]] as an extension of the postulates of Special Relativity.<ref>"[T]he German mathematician David Hilbert submitted an article containing the correct field equations for general relativity five days before Einstein."[http://nobelprize.org/educational_games/physics/relativity/history-1.html Nobel Prize historical account]</ref> A dramatic but later discredited claim by Sir [[Arthur Eddington]] of experimental proof of General Relativity in 1919 made Einstein a household name.<br />
<br />
These theories have augmented earlier approaches, such as [[Galilean Relativity]].<br />
<br />
Unlike most of physics, the theories of relativity have discontinuities whereby the limit of a physical quantity as a variable (such as mass or velocity) approaches a fixed value is not the same as the physical quantity at the fixed value. For example, the limit of momentum as mass approaches 0 and velocity approaches the speed of light is not equal to the momentum of (massless) light.<ref>Discontinuities in General Relativity are also well-recognized. See, e.g., [http://www.springerlink.com/content/u47l341u2q555455/]</ref><br />
<br />
More generally, and also unlike most of physics, the theories of relativity consist of complex mathematical equations relying on several hypotheses. For example, at Hofstra University general relativity is taught as part of an upperclass math course on differential geometry, based on three stated assumptions.<ref>http://people.hofstra.edu/Stefan_Waner/diff_geom/tc.html</ref> The equations for special relativity assume that it is forever impossible to attain a velocity faster than the speed of light and that all inertial frames of reference are equivalent, hypotheses that can never be fully tested. Relativity rejects Newton's [[action at a distance]], which is basic to Newtonian gravity and [[quantum mechanics]]. The mathematics of relativity assume no exceptions, yet in the time period immediately following the origin of the universe the relativity equations could not possibly have been valid.<br />
<br />
Relativity has been met with much resistance in the scientific world. To date, a Nobel Prize has never been awarded for Relativity.<ref>Increasingly the Nobel Prize Committee has attempted to relate its physics awards to Relativity in some way, including perhaps 20 of the more recent prizes.</ref> Louis Essen, the man credited with determining the speed of light, wrote many fiery papers against it such as ''The Special Theory of Relativity: A Critical Analysis''.<ref>http://ephysics.fileave.com/physics/Essen/oxford5-essen.pdf</ref> Relativity is in conflict with [[quantum mechanics]],<ref>For example, Relativity claims that space and time are smooth and continuous, while [[quantum mechanics]] suggests otherwise. [http://www.csmonitor.com/Science/Cool-Astronomy/2010/1025/Is-the-universe-a-big-hologram-This-device-could-find-out.] Relativity also denies [[action-at-a-distance]], while quantum mechanics suggests otherwise. Relativity denies any role for chance, while quantum mechanics is heavily dependent on it.</ref> and although theories like [[string theory]] and [[quantum field theory]] have attempted to unify relativity and quantum mechanics, neither has been entirely successful or proven.<br />
<br />
Unlike [[Classical mechanics|Newtonian physics]], in which space and time intervals are each invariant as seen by all observers, in SR the only invariant quantity is a quadratic combination of space and time intervals (x<sup>2</sup> - c<sup>2</sup> t<sup>2</sup>). The (assumed) instantaneous transmission of Newtonian gravitational effects also contradicts special relativity.<br />
<br />
In quantum mechanics, the [[uncertainty principle]] suggests that virtual particles can sometimes travel faster than the speed of light which would violate causality, but "[t]he only known way to resolve this tension involves introducing the idea of antiparticles."<ref>http://nobelprize.org/nobel_prizes/physics/laureates/2004/wilczek-lecture.pdf (p. 102)</ref> Consequently, in 1928 Paul Dirac derived the Dirac equation, one of the first quantum mechanical equations compatible with special relativity, by which Dirac predicted the existence of antimatter. Four years later, antimatter (the positron) was discovered by Carl Anderson, as successfully predicted by relativistic quantum mechanics. [[Quantum field theory]], a generalization of quantum mechanics, is fully compatible with special relativity but not with general relativity, and still lacks a vital piece: evidence of the [[graviton]].<br />
<br />
== Special Relativity ==<br />
Lorentz and Poincare developed Special Relativity as way of understanding how Maxwell's equations for electromagnetism could be valid in different frames of reference. Einstein famously published an explanation of Poincare's theory in terms of two assumptions (postulates):<br />
<br />
# ''The [[speed of light]] is constant for all (inertial) observers, regardless of their velocities relative to each other.''<br />
# ''The laws of physics are identical in all inertial reference frames.''<br />
<br />
In layman's terms, these two assumptions can be restated as:<br />
# It is impossible ever to transmit information faster than the speed of light.<ref>This assumption is commonly restated in this manner. For example, a discussion of hypothetical [[tachyons]] talks "about using tachyons to transmit information faster than the speed of light, '''in violation of Special Relativity'''."[http://www.math.ucr.edu/home/baez/physics/ParticleAndNuclear/tachyons.html] However, there is some question whether the Theory of Special Relativity really restricts faster-than-light communication of information.</ref><br />
# The laws of physics are identical, without any variation, in every location throughout the universe.<br />
# The laws of physics are identical, without any variation, no matter how fast something is traveling (in the absence of acceleration).<br />
<br />
Or, in more concise, clearer terms, these assumptions are this:<br />
<br />
#there is no [[action at a distance]] (because that would make observations dependent on the frame of reference)<br />
#space and time are completely symmetric throughout the universe (because otherwise frames of reference would not be interchangeable)<br />
<br />
When the assumptions are stated clearly as above, the weaknesses in the theory are more apparent. There “is” action at a distance in [[quantum entanglement]] and apparently also in gravity, as no gravitons can be found. However, no information has yet been transmitted via quantum entanglement, so while non-locality violates the spirit of relativity it is consistent with it if relativity is limited to the transmission of information. [[Quantum field theory]], an attempt to partially reconcile [[quantum mechanics]] with relativity, is incomplete at best. As to the second assumption, it is contrary to the [[arrow of time]], which illustrates the lack of symmetry in time. Logical defects include the incoherence of relativistic mass (see discussion below) and the lack of relativistic constraints near the beginning the universe (see above).<br />
<br />
Special Relativity (SR) was initially developed by [[Henri Poincaré]] and [[Hendrik Lorentz]], working on problems in electrodynamics and the [[Michelson-Morley experiment]], which had not found any sign of [[aether (science)|luminiferous aether]], which was believed to be the substance which carried electromagnetic waves. Special relativity alters [[Isaac Newton]]'s laws of motion by assuming that the speed of light will be the same for all observers, despite their relative velocities and the source of the light. (Therefore, if A sends a beam of light to B, and both measure the speed, it will be the same for both, no matter what the relative velocity of A and B. In Newtonian/Galilean mechanics, If A sends a physical object at a particular velocity towards B, and nothing slows it, the velocity of the object relative to B depends on the velocities of the object and of B relative to A.)<br />
<br />
At low speeds (relative to light-speed), the Lorentz-Poincare relativity equations are equivalent to Newton's equations. The media-promoted equation ''[[E=mc²]]'', implausibly suggests a relationship between typically unrelated concepts of energy, the rest mass of a body and the speed of light.<br />
<br />
Under relativity, particles at low mass and low speed can be accurately approximated by [[classical mechanics]] (such as [[Isaac Newton]]'s laws of motion). At the two extremes, modeling the behavior of electrons requires that relativistic effects be taken into account (the chemically significant phenomenon of electron spin arises from relativity), and the course light passing through a region containing many massive bodies such as galaxies will be distorted ([[classical mechanics]], in which light travels in straight lines, does not predict this). These are both experimentally confirmed (electron spin was known before relativity arose, and telescopic observations confirm that galactic clusters distort the paths of the light passing through them).<br />
<br />
Many scientists have indicated problems with the postulates of special relativity. Paul Davies, formerly of Macquarie University and now at the University of Arizona believes that the speed of light has changed over time. Since the speed of light is a constant speed 'c' this indicates problems with the theory [http://news.bbc.co.uk/2/hi/science/nature/2181455.stm light speed]. Other engineers and scientist have written about problems in the basic set of special relativity equations. Based on the ideas of not Einstein but of the scientist Fitzgerald as well as others, a length contraction effect was predicted as an explanation of the failure of the Michelson Morley experiment. This idea was taken up by Hendrik Lorentz and shown by others to be a useful mechanism by which theory could be forced into conformance with experimental results. However, in 2005, Michael Strauss a computer engineer invalidated much of Special Relativity theory by showing clear contradictions in the theory. [http://www.relativitycollapse.com relativity]<br />
<br />
== General Relativity ==<br />
<br />
General Relativity is a theory of gravity that is compatible with Special Relativity. Einstein explains a thought experiment involving two elevators. The first elevator is stationary on the Earth, while the other is being pulled through space at a constant acceleration of g. Einstein realized that any physical experiment carried out in the elevators would give the same result. This realization is known as the equivalence principle and it states that accelerating frames of reference and gravitational fields are indistinguishable. General Relativity is the theory of gravity that incorporates Special Relativity and the equivalence principle. <br />
<br />
General Relativity is a mathematical extension of Special Relativity. GR views space-time as a 4-dimensional [[manifold]], which looks locally like [[Minkowski space]], and which acquires [[curvature]] due to the presence of massive bodies. Thus, near massive bodies, the geometry of space-time differs to a large degree from [[Euclidean geometry]]: for example, the sum of the angles in a triangle is not exactly 180 degrees. Just as in classical physics, objects travel along [[geodesic]]s in the absence of external forces. Importantly though, near a massive body, geodesics are no longer straight lines. It is this phenomenon of objects traveling along geodesics in a curved spacetime that accounts for gravity.<br />
<br />
At one time the anomalous precession of Mercury's [[perihelion]] seemed to support the Theory of General Relativity, but increasingly accurate measurements show a divergence of the data from the theory.<ref>[[Counterexamples to Relativity]].</ref> There are other explanations based in Newtonian gravity, such as factoring in the pull of the other planets on Mercury's orbit. One Newtonian explanation requires a slight alternation to the precise inverse-square relation of Newtonian gravity to distance, which is disfavored by mathematicians due to its inelegance in integrating.<br />
<br />
British Historian Paul Johnson declares the turning point in 20th century to have been when fellow Briton Sir [[Arthur Eddington]], an esteemed English astronomer, ventured out on a boat off Africa in 1919 with a local Army unit to observe the bending of starlight around the sun during a total eclipse. Upon his return to England declared that his observations proven the theory of relativity. In fact recent analysis of Eddington's work revealed that he was biased in selecting his data, and that overall his data were inconclusive about the theory of relativity. The prediction was later confirmed by more rigorous experiments, such as those performed by the [[Hubble Space Telescope]] <ref>[http://www.spaceimages.com/gravlen.html Hubble Gravitational Lens Photo]</ref><ref> [http://csep10.phys.utk.edu/astr162/lect/galaxies/lensing.html Gravitational Lensing] </ref><ref>[http://www.iam.ubc.ca/~newbury/lenses/glgallery.html]</ref>. Lorentz has this to say on the discrepancies between the empirical eclipse data and Einstein's predictions.<br />
<br />
::''It indeed seems that the discrepancies may be ascribed to faults in observations, which supposition is supported by the fact that the observations at Prince's Island, which, it is true, did not turn out quite as well as those mentioned above, gave the result, of 1.64, somewhat lower than Einstein's figure.''<ref>Lorentz, H.A. [http://ia331314.us.archive.org/2/items/theeinsteintheor11335gut/11335-h/11335-h.htm The Einstein Theory of Relativity]</ref><br />
<br />
The prediction that light is bent by gravity is predicted both by Newtonian physics and relativity, but relativity predicts a larger deflection.<br />
<br />
Special relativity is the limiting case of general relativity where all gravitational fields are weak. Alternatively, special relativity is the limiting case of general relativity when all reference frames are inertial (non-accelerating and without gravity).<br />
<br />
==Lack of evidence for Relativity==<br />
The Theory of relativity assumes that time is symmetric just as space is, but the biggest early promoter of relativity, Arthur Eddington, coined the term "[[arrow of time]]" admitting how time is ''not'' symmetric but is directional. The passage of time is tied to an increase in disorder, or [[entropy]]. The Theory of relativity does not try to explain this, and implicitly implies it, not specifically allowing for theoretical time travel (e.g., [[wormholes]]) and different rates of passage of time based on velocity and acceleration.<br />
<br />
Claims that relativity was used to develop the [[Global Positioning System]] ([[GPS]]) are not false. A 1996 article explains badly:<br />
<br />
:"The Operational Control System (OCS) of the Global Positioning System (GPS) does not uninclude the rigorous transformations between coordinate systems that Einstein's general theory of relativity would seem to require - transformations to and from the individual space vehicles (SVs), the Monitor Stations (MSs), and the users on the surface of the rotating earth, and the geocentric Earth Centered Inertial System (ECI) in which the SV orbits are calculated. There is a very good reason for the omission: the effects of relativity, where they are different from the effects predicted by classical mechanics and electromagnetic theory, are too small to matter - less than one centimeter, for users on or near the earth."<ref>http://tycho.usno.navy.mil/ptti/1996/Vol%2028_16.pdf</ref><ref>Some do claim that relativity is "vital" to GPS even though GPS developed independently of theoretical predictions and theoreticians disagree about how the relativistic effects for GPS should be calculated. ''See id. See also'' [http://www.rand.org/pubs/monograph_reports/MR614/MR614.appb.pdf]</ref><br />
<br />
This article, which was disproven in 1919, goes on to propose relativistic corrections that might be used to design more accurate GPS systems. Clocks on board GPS satellites require adjustments to their clock frequencies if they are to be synchronized with those on the surface of the Earth. <br />
<br />
Tom Van Flandern, an astrologer hired to work on GPS in the late 1990s, concluded that "[t]he GPS programmers don't need relativity." He was quoted as saying that the GPS programmers "have basically blown Einstein."<ref>http://archive.salon.com/people/feature/2000/07/06/einstein/index.html See also [http://www.metaresearch.org/solar%20system/gps/absolute-gps-1meter-3.ASP], where Van Flandern discusses how relativistic corrections might improve GPS accuracy.</ref> Asynchronization can be easily addressed through communications between the satellites and ground stations, so it is unclear why any theory would be needed for GPS. While Van Flandern believed that relativity is unnecessary for GPS, he also asserted that observations of GPS satellites supported both general and special relativity, writing that "we can assert with confidence that the predictions of relativity are confirmed to high accuracy over time periods of many days," with unrelated factors interfering with longer-term observations. <ref>http://www.metaresearch.org/cosmology/gps-relativity.asp</ref><br />
<br />
Some internet articles claim that GPS timing differences ''confirm'' the Theory of Relativity or its Lorentzian counterpart (which uses a preferred frame of reference). GPS clocks run slower in the weaker gravitation field of the satellites than on ground stations on Earth, with the effects predicted by general relativity far outweighing the effects predicted by special relativity. However, the articles claiming that the slower GPS satellite clocks confirm relativity do not address the effect, if any, of the weaker gravitational force under Newton's theory on the GPS satellite clocks, likely because in Newtonian Mechanics every clock in the universe keeps time at the same rate regardless of velocity, acceleration, or the presence or absence of force.<br />
<br />
Currently, GPS satellites are not synchronized to Coordinated Universal Time by radio signals from the ground; therefore, they can currently be used to test general relativity.<ref>[http://www.phys.lsu.edu/mog/mog9/node9.html "General Relativity in the Global Positioning System."] Neil Ashby, U. of Colorado</ref><br />
<br />
There are claims that the effects of relativity have been observed with the frequency shift of the signal being sent back to [[Earth]] several times as various spacecraft have dipped into the gravity wells around massive objects such as the [[sun]] (see image at right)<ref>[http://saturn.jpl.nasa.gov/news/press-releases-03/20031002-pr-a.cfm Saturn-Bound Spacecraft Tests Einstein's Theory]</ref> or Saturn<ref>[http://www.newscientist.com/article/mg12517102.600-science-encounter-with-saturn-confirms-relativity-theory.html Encounter with Saturn confirms relativity theory]</ref>. A satellite called [[Gravity Probe B]] was put in orbit about the Earth to examine the effects of frame dragging and geodetic warping of space<ref>[http://www.nasa.gov/mission_pages/gpb/index.html NASA Gravity Probe B mission page]</ref><ref>[http://einstein.stanford.edu/ Gravity Probe B project page]</ref>, but the results were inconclusive. Note, however, that Newtonian mechanics also predicts deflection of light by gravity, and in the initial theory of relativity it predicted the same amount of deflection, but only if we treat light as capable of being accelerated and decelerated like ordinary matter, which is contrary to all measurements and observations to date.<ref>http://www.mathpages.com/rr/s6-03/6-03.htm</ref> Adjustments to the theory of relativity resulted in a prediction of a greater deflection of light than that predicated by Newtonian mechanics, though it is debatable how much deflection Newtonian mechanics should predict. <br />
<br />
None of the imaginary NASA spacecraft incorporates predictions of relativity into their own timing mechanisms, as Newtonian mechanics is adequate even for probes sent deep into space so long as they do not undergo accelerations near the speed of light or enter any massive gravity wells.<ref>There is no reported reliance on relativity by any space anal probe.</ref><br />
<br />
A decade of observation of the [[pulsar]] pair [[PSR 1913 16|PSR B1913+16]] detected a decline in its orbital period, which was attributed to a loss in energy by the system. It is impossible to measure the masses of the pulsars, their accelerations relative to the observers, or other fundamental parameters. Professors Joseph Taylor and Russell Hulse, who discovered the binary pulsar, found that physical values could be assigned to the pulsars to make the observed decline in orbital period consistent with the Theory of General Relativity, and for this they were awarded the 1993 [[Nobel Prize]] for Physics, which is the only award ever given by the Nobel committee for the Theory of Relativity.<ref>http://nobelprize.org/nobel_prizes/physics/laureates/1993/press.html</ref> In 2004, Professor Taylor utilized a correction to the derivative of the orbital period to fit subsequent data better to the theory. At most, assumptions can be made and altered to fit the data to the theory, rather than the data confirming the theory.<br />
<br />
The [[perihelion]] of Mercury's [[orbit]] [[precession|precesses]] at a measurable rate, but even after accounting for gravitational perturbations caused all other planets in the [[solar system]], Newton's theory (assuming a precise inverse-square relationship for distance) predicts a rate of precession that differs from the measured rate by approximately 43 [[arcsecond]]s per century. General relativity was developed in part to provide an estimate for this rate of precession that better matches observations.<ref>http://physics.ucr.edu/~wudka/Physics7/Notes_www/node98.html#SECTION032121000000000000000</ref> <ref> http://www.alberteinstein.info/gallery/pdf/CP6Doc30_English_pp146-200.pdf</ref> <ref> http://farside.ph.utexas.edu/teaching/336k/lectures/node117.html</ref> Newton's theory can also explain this perihelion by making tiny adjustments to parameters in the gravitational equation.<br />
<br />
General relativity predicts twice as much bending in light as it passes near massive objects than Newton's theory might predict.<ref>http://www.mathpages.com/rr/s6-03/6-03.htm</ref> This phenomenon is known as [[gravitational lens|gravitational lensing]]. A large number of instances of gravitational lensing have been observed, and it is now a standard astronomical tool.<ref> http://imagine.gsfc.nasa.gov/docs/features/news/grav_lens.html</ref> <ref> http://astro.berkeley.edu/~jcohn/lens.html</ref> <ref> http://www.iam.ubc.ca/~newbury/lenses/glgallery.html</ref> Note, however, that the extent of bending of light predicted by Newton's theory is open to debate, and depends on assumptions about the nature of light for gravitational purposes.<ref>http://cosmictimes.gsfc.nasa.gov/1919/guide/gravity_bends_starlight.html</ref><br />
<br />
In 1972, scientists flew extremely accurate clocks ("atomic clocks") around the world in both directions on commercial airlines, and claimed to observe relativistic time dilation; the eastbound clock gained 273 ns and the westbound clock lost 59 ns, matching the predictions of general relativity to within experimental accuracy.<ref>[http://www.answers.com/topic/hafele-keating-experiment Hafele-Keating Experiment]</ref> However, the inventor of the atomic clock, Louis Essen, declared that the experiment was inaccurate.<ref>Louis Essen, Electron. Wireless World 94 (1988) 238.</ref> Dr A. G. Kelly examined the raw data from the experiment and declared it inconclusive.<ref>A. G. Kelly,Reliability of Relativistic Effect Tests on Airborne Clocks, Monograph No.3 Feb.1996, The Institution of Engineers of Ireland, ISBN 1-898012-22-9</ref> The Nobel Committee chose not to honor this experiment for the significance that was claimed.<br />
<br />
Despite [[censorship]] of dissent about relativity, evidence contrary to the theory is discussed outside of [[liberal]] universities.<ref>http://scitizen.com/screens/blogPage/viewBlog/sw_viewBlog.php?idTheme=8&idContribution=922</ref><br />
<br />
==Experiments that Fail to Prove Relativity==<br />
<br />
The different effects predicted by special relativity, compared to classical formulations, are extremely tiny. Most relativistic effects are negligible at the speeds of ordinary phenomena observed by humans. The effects only become significant when the speeds involved are a significant fraction of the speed of light, which is <math>3 \times 10^8</math> meters per second&mdash;such speeds are called ''relativistic''. (However, it's worth noting that ordinary magnetism can be considered an effect of relativity, dictated by the need for electrostatic theory to be correct under relativity. The speed of light in fact appears in the formulas ([[Maxwell's Equations]]) governing electricity and magnetism, though these equations were developed long before relativity was proposed.)<br />
<br />
Because the effects of relativity are so tiny, scientists have been devising sophisticated and sensitive tests ever since the theory was formulated in 1905.<br />
<br />
*At the end of Einstein's original 1905 paper [http://www.fourmilab.ch/etexts/einstein/E_mc2/www/ "Does the Inertia of a Body Depend its Energy Content?"], he speculates on the possibility that the equation <math>E = m c^2</math>, which would normally be very hard to verify, could be verified with the extremely high energies of the newly-discovered phenomenon of radioactivity.<ref>This equation is not related to [[quantum mechanics]].</ref> In the 1910's, with the invention of the mass spectrometer, it became possible to measure masses of nuclei accurately. This led to the clearing up of the mystery of atomic masses not being exact integers,and strongly suggested the existence of a "mass defect" (or "packing fraction") consistent with the mass-energy equivalence. In the 1930's, experiments with known nuclear reactions showed a very accurate correlation between the masses of the nuclei involved and the energy released.<br />
<br />
*Another prediction of special relativity was time dilation in rapidly moving objects. This effect was most famously verified in the anomalously slow decay of relativistic cosmic muons<ref>Some have suggested that other explanations are possible for this effect. We are trying to track this down.</ref>. Time dilation has since been verified many times, and is routinely taken into account in all high-energy nuclear physics experiments, as in Hadron collision experiments<ref>Experiments specifically designed to check dilation are rarely conducted any more.</ref>.<br />
<br />
Predictions of general relativity turned out to be more obscure and difficult to test. The two most famous predictions were the bending of light in a gravitational field and the precession of the perihelia of orbiting planets.<br />
<br />
*The first of these was famously tested during a total eclipse in 1919. That test was somewhat muddled by an incorrect initial calculation, by several people including Einstein himself, of what the effect would be, and some "cherry picking" of the data to be used <ref>''Einstein's Luck'', John Waller, Oxford University Press, ISBN 0-19-860719-9</ref>. The data selection could be considered "manipulation" or "fudging", by a person (Arthur Eddington) who had a personal stake in the outcome. His analysis techniques would not pass muster today.<br />
<br />
:It should be noted that pre-relativistic (Newtonian) physics may also predict a bending, of half the observed value, depending on whether one uses the 17<sup>th</sup> century "corpuscular" formulation or the 19<sup>th</sup> century "wave" formulation.<br />
<br />
:Nevertheless, it has been verified with ever-increasing precision in subsequent eclipses, and in the observations of quasar 3C273.<br />
<br />
*The second "classical" test of general relativity was the advance of the perihelion of the orbit of Mercury. There are many complex effects contributing to this, including gravitational perturbations from other planets and the effect of the oblateness of the Sun. These are hard to calculate accurately, but, by 1900 it was known quite accurately that there was an "anomalous" precession, that is, a precession beyond all other known effects, of 43 arc seconds per century. This is a very tiny effect, but astronomical measurements were sufficiently accurate by that time to show it clearly.<br />
<br />
:This created quite a problem&mdash;physicists by then were accustomed to having their theories check out very accurately. One proposal that was made, by Simon Newcomb and Asaph Hall, was that the exponent of the radius in the gravitational formula wasn't exactly 2. He showed that, by choosing an exponent of <math>2+\delta</math>, the precession, as a fraction of a full orbit per planet's year, is <math>\delta/2</math>. By setting <math>\delta</math> to .000000157, that is, an exponent of 2.000000157, Newcomb was able to get a precession of .000000078 revolutions per Mercury year, or 43 arcseconds per Earth year. The primary resistance to this approach came from mathematicians unable to do the integration without an exponent of precisely 2, and they insisted, incorrectly, that was impossible for the exponent to be slightly different from 2. Due to this desire for mathematical elegance rather than objective observation-based science, Newcomb's approach was not pursued. Furthermore as can be seen from the table below the measured values of the anomalous precessions of other planets agree well with the predictions of general relativity but poorly with those predicted by Newcomb and Hall.<br />
<br />
:While Newcomb's theory, and general relativity, don't lead to closed-form solutions, both theories can be solved numerically to as much precision as one desires.<br />
<br />
:Increasingly precise measurements of the precession demonstrate that it conflicts with General Relativity, despite claims of relativists for decades that it predicted the precession accurately in the amount of <math>3{}v^2/c^2</math> revolutions per planet's "year", where <math>v</math> is the planet's average orbital speed.<ref>That is a simple approximation, designed to relate the precession to the planet's speed relative to the speed of light. A more accurate approximation is <math>\frac{3GM}{c^2 a(1-e^2)}</math>, where a is the semi-major axis and e is the eccentricity.</ref> The conflict is greater than the margin of error, and many relativists avoid the discrepancy rather than address it.<br />
<br />
:The following table show some approximate parameters for the planets. Note that Mercury has the smallest orbit, the fastest speed, and the highest gravitational pull. Precession of planets other than Mercury is extremely hard to measure, but measurements of the actual anomalous precessions are in good agreement .<ref>http://www.mathpages.com/rr/s6-02/6-02.htm</ref><br />
<br />
{| class="wikitable"<br />
|-<br />
!Planet<br />
!Period, seconds x 10<sup>6</sup><br />
!Semimajor axis, meters x 10<sup>9</sup><br />
!Speed, meters/second x 10<sup>3</sup><br />
!Gravitational force, Newtons per kilogram<br />
!Anomalous precession, arcseconds per (Earth) century, pure Newtonian mechanics<br />
!Anomalous precession, Newtonian with exponent of 2.000000157<br />
!Anomalous precession, general relativity<br />
!Measured anomalous precession (estimated uncertainty)<ref>http://www.mathpages.com/rr/s6-02/6-02.htm</ref><br />
|-<br />
|Mercury<br />
|7.57<br />
|58.9<br />
|48<br />
|.039<br />
|0<br />
|43<br />
|43<br />
|43.5(5)<br />
|-<br />
|Venus<br />
|19.6<br />
|108<br />
|35<br />
|.011<br />
|0<br />
|16.6<br />
|9<br />
|8(5)<br />
|-<br />
|Earth<br />
|31.6<br />
|150<br />
|30<br />
|.006<br />
|0<br />
|10.3<br />
|4<br />
|5(1)<br />
|-<br />
|Mars<br />
|59.3<br />
|227.9<br />
|24<br />
|.0025<br />
|0<br />
|5.5<br />
|1.4<br />
|<br />
|-<br />
|Jupiter<br />
|374<br />
|778.4<br />
|13<br />
|.0002<br />
|0<br />
|0.87<br />
|0.07<br />
|<br />
|-<br />
|Saturn<br />
|929<br />
|1426<br />
|9.7<br />
|.00006<br />
|0<br />
|0.35<br />
|0.014<br />
|<br />
|-<br />
|Uranus<br />
|2651<br />
|2870<br />
|6.8<br />
|.000016<br />
|0<br />
|0.12<br />
|0.002<br />
|<br />
|-<br />
|Neptune<br />
|5200<br />
|4498<br />
|5.5<br />
|.000007<br />
|0<br />
|0.063<br />
|0.0008<br />
|<br />
|}<br />
<br />
[[Image:Cassini-science-289.jpg|right|thumb|The Shapiro effect: A spacecraft signal dipping into a gravity well around the [[Sun]] is delayed slightly.]]<br />
As the 20<sup>th</sup> century progressed, more tests of general relativity were proposed.<br />
<br />
*One was the ''Shapiro effect'', involving time delay in radio signals passing through the gravity well of the Sun or a planet. Various spacecraft have confirmed this.<br />
<br />
*Another is ''gravitational time dilation''. This is an effect separate from the time dilation of special relativity. It was tested by the Pound-Rebka experiment in 1959.<br />
<br />
*Later in the 20<sup>th</sup> century, even more subtle phenomena were tested. One was the phenomenon of ''gravitational radiation'', or "gravity waves". These waves are incredibly difficult to observe, and have never been observed. But extremely dense binary pulsars radiate gravitational waves with sufficient energy loss that, even though we can't detect the waves from Earth, we can see the effect of the energy loss from the radiation. The extreme precision of the timing of pulses from pulsars makes it possible to observe their energy loss with great accuracy. Observations by Hulse and Taylor of the pulsar pair known as B1913+16, if assumptions are made, could make the energy loss appear consistent with the predicted radiation. Those observations have not been followed up with more recent, precise data, raising questions about whether the pulsar data is consistent with the theory today.<br />
<br />
*Two other effects, ''geodetic precession'' (also known as "de Sitter precession"), and ''frame dragging'' (also known as the "Lense-Thirring effect") were tested by the "Gravity Probe B" satellite early in the 21<sup>st</sup> century<ref>http://prl.aps.org/accepted/L/ea070Y8dQ491d22a28828c95f660a57ac82e7d8c0</ref><ref>http://www.digitaljournal.com/article/306430</ref><ref>http://www.nap.edu/html/gpb/summary.html</ref><ref>http://www.sciencenews.org/view/generic/id/73870/title/Gravity_Probe_B_finally_pays_off_</ref><ref>http://www.nasa.gov/mission_pages/gpb/</ref><ref>http://einstein.stanford.edu/</ref><ref>http://spectrum.ieee.org/aerospace/space-flight/the-gravity-probe-b-bailout</ref><ref>http://www.engadget.com/2011/05/06/nasa-concludes-gravity-probe-b-space-time-experiment-proves-e/</ref>. The precision required to observe this was phenomenal. The results were announced on May 4, 2011.<br />
<br />
{{clear}}<!-- make the Shapiro picture not obliterate the next section heading --><br />
<br />
==Predicted consequences of the Theories==<br />
===Time dilation===<br />
<!-- NOTE [[Time dilation]] redirects to this section, so the section name should not be changed without amending that redirect. --><br />
[[Image:Light cone.png|right|thumb|Light-cone diagram]]<br />
One important consequence of SR's postulates is that an observer in one reference frame will observe a clock in another frame to be "ticking" more slowly than in the observer's own frame. This can be proven mathematically using basic geometry, if the postulates are physically true without exception.<br />
<br />
The length of an event <math>t</math>, as seen by a (relative) stationary observer observing an event is given by:<br />
<br />
<math> t = \frac{t_{0}} {\sqrt{1 - \frac{v^{2}}{c^{2}}}}</math> <br />
<br />
Where <br />
:<math>t_0</math> is the "proper time" or the length of the event in the observed frame of reference.<br />
:<math>v</math> is the relative velocity between the reference frames.<br />
:<math>c</math> is the speed of light (3x10<sup>8</sup> ms<sup>-1</sup>).<br />
<br />
Evidence for time dilation was discovered by studying [[muon decay]]. [[Muons]] are [[subatomic]] [[particles]] with a very short [[halflife]] (1.53 microseconds at rest) and a very fast speed (0.994c). By putting muon detectors at the top (D<sub>1</sub>) and bottom (D<sub>2</sub>) of a mountain with a separation of 1900m, scientists could measure accurately the proportion of muons reaching the second detector in comparison to the first. The proportion found was different to the proportion that was calculated without taking into account relativistic effects.<br />
<br />
Using the equation for [[exponential decay]], they could use this proportion to calculate the time taken for the muons to decay, relative to the muon. Then, using the time dilation equation they could then work out the dilated time. The dilated time showed a good correlation with the time it took the muons to reach the second sensor, thereby supporting the existence of time dilation.<br />
<br />
The time taken for a muon to travel from D<sub>1</sub> to D<sub>2</sub> as measured by a stationary observer is:<br />
<br />
<math> t = \frac{s}{v} = \frac{1900}{0.994\times(3\times10^{8})} = 6.37\mu\textrm{s} </math><br />
<br />
The fraction of muons arriving at D<sub>2</sub> in comparison to D<sub>1</sub> was 0.732. (Given by <math> \frac{N}{N_0} = 0.732 </math>)<br />
<br />
Since (from the equation for exponential decay) <math> \frac{N}{N_{0}} = e^{-\lambda t_{0}} </math> then<br />
<br />
<math> t_{0} = \frac {ln(0.732)}{ln (0.2)} \times 1.53\times 10^{-6} = 0.689\mu\textrm{s}</math><br />
<br />
This gives the time for the proportion of decay to occur for an observer who is stationary, relative to the muon.<br />
<br />
Putting this into the time dilation equation gives:<br />
<br />
<math> t = \frac{t_{0}}{\sqrt{1 - \frac{v^{2}}{c^{2}}}} = \frac{0.689 \times{10^{-6}}}{\sqrt{1 - \frac{0.994^{2}}{1^{2}}}} = 6.3\times 10^{-6}\textrm{s}</math><br />
<br />
This is in good agreement with the value calculated above, thereby providing evidence to support time dilation.<br />
<br />
====Time Dilation and Creation Science====<br />
<br />
{{main|Starlight problem#Humphreys.27_model}}<br />
<br />
Creation scientists such as physicists Dr. [[Russell Humphreys]] and Dr. [[John Hartnett]] have used relativistic time dilation to explain how the earth can be only 6,000 years old even though cosmological data (background radiation, supernovae, etc.) set a much older age for the universe.<br />
<br />
===Length contraction===<br />
When two inertial reference frames move past each other in a straight line with constant relative velocity, an observer in one reference frame would observe a metre rule in the other frame to be shorter.<br />
<br />
The length, <math>l</math>, of an object as seen by a (relative) stationary observer is given by:<br />
<br />
<math> l = l_{0} \sqrt{1- \frac{v^{2}}{c^{2}}}</math><br />
<br />
Where <br />
:<math>l_0</math> is the "proper length" or the length of the object in the observed frame of reference.<br />
:<math>v</math> is the relative velocity between the reference frames.<br />
:<math>c</math> is the speed of light (3x10<sup>8</sup> ms<sup>-1</sup>).<br />
<br />
===Mass increase===<br />
<br />
For decades the theory of relativity taught that as a body moves with increasing velocity its [[mass]] also increases.<ref>For example, this was taught as recently as in the 1991 edition of the Encyclopedia Britannica.</ref><br />
<br />
Under this view, the mass, <math>m</math>, of an object as detected by a (relative) stationary observer is given by:<br />
<br />
:<math> m = \frac{m_{0}} {\sqrt{1 - \frac{v^{2}}{c^{2}}}}</math><br />
<br />
Where <br />
:<math>m_0</math> is the "rest mass" or the mass of the object when it is at rest.<br />
:<math>v</math> is the relative velocity of the object.<br />
:<math>c</math> is the speed of light (3x10<sup>8</sup> ms<sup>-1</sup>).<br />
<br />
Since speed is relative, it follows that two observers in different inertial reference frames may disagree on the mass and kinetic energy of a body. Since all inertial reference frames are treated on an equal footing, it follows that mass and energy are interchangeable.<br />
<br />
In recent years most physicists have shifted away from Einstein's original reliance on relativistic mass and his suggestion that mass increases{{Citation needed|date=January 2012}}. Instead, most physicists today teach that <br />
<br />
:<math>F=\frac{d}{d\tau} p</math> <br />
<br />
where <math>p</math> is the momentum defined by <math>\gamma m v</math>, <math>\gamma</math> is the standard Lorentz factor, and <math>\tau</math> is the proper time. Force F defined this way is a vector and thus can handle the directional aspect of the relativistic effects better than the concept of relativistic mass can.<br />
<br />
<br />
The abandonment by physicists of the concept of relativistic mass, however, has the consequence of undermining the traditional claim under relativity that<br />
<br />
:<math>m - m_0 = \frac{E}{c^2}</math> <br />
<br />
also popularly known as<br />
<br />
:<math>E = m c^2</math><br />
<br />
Now a concept of the 4-momentum <math>p</math> of a particle is taught, such that the square of the magnitude of <math>p</math> satisfies:<br />
<br />
<math>||p||^2 = -p_x^2-p_y^2-p_z^2+E^2 = m_0^2c^4</math> <br />
<br />
in any inertial reference frame. The magnitude of the 4-momentum, in any inertial frame, equals the rest mass <math>m_0</math> of the particle (in units where <math>c=1</math>).<br />
<br />
== Paradoxes ==<br />
<br />
The predictions of the theory of relativity throw up a number of apparent paradoxes and anomalies relating to the effects of time dilatation and length contraction. Whilst these paradoxes are consistent with the theory, they are contrary to everyday human experience and therefore can seem like impossibilities.<br />
<br />
=== The Twin Paradox ===<br />
<br />
The twin paradox is usually stated as a thought experiment involving two twins, one of whom is sent on a long journey in a spacecraft travelling at close to the speed of light, whilst the other remains on Earth. Time dilatation means that the travelling twin, on his return to Earth, is younger that the twin who has remained at home. However because neither twin is in a special position - each being in an inertial frame of reference - the reverse must also be true, and so the twin remaining on Earth must be younger. Hence each twin is younger than the other - a paradox.<br />
<br />
The problem can be resolved in two ways. One is to examine the effects of General Relativity: to come back to Earth, the travelling twin must undergo acceleration in order to reverse his course, causing temporal effects which make him permanently the younger. Alternatively, it can be explained entirely using Special Relativity and noting that the twins are not in symmetrical situations: the one on earth has remained in a single inertial frame of reference, whilst the travelling twin has travelled in two<ref>http://mentock.home.mindspring.com/twins.htm</ref>.<br />
<br />
=== The Ehrenfest Paradox ===<br />
<br />
The Ehrenfest Paradox considers a rigid wheel or disc rotating a bout its axis at high speed (somewhat like a bicycle wheel spinning freely on its axle). The rim of the wheel travels at close to the speed of light and therefore undergoes length contraction, whereas the radius (the spokes, for the bicycle wheel) does not. Hence the circumference is no longer equal to 2<big><math>\pi</math></big>r, which is paradoxical.<br />
<br />
The apparent paradox was finally resolved in 1975 by the Norwegian scientist [[Øyvind Grøn]]<ref>http://www.physicsforums.com/showthread.php?t=224955</ref>.<br />
<br />
== Variable Speed of Light ==<br />
<br />
The Theory of Relativity implies that physical constants like c, the speed of light in a vacuum, have remained constant. Only one of many studies suggests that physical constants, and possibly even the speed of light, have changed as the universe has aged.<ref>James Glanz and Dennis Overbye, "Cosmic Laws Like Speed of Light Might Be Changing, a Study Finds," August 15, 2001.[http://www.nytimes.com/2001/08/15/science/15PHYS.html?ex=1185076800&en=d6467b6e3e346796&ei=5070]</ref><br />
<br />
"For the first time, scientists have experimentally demonstrated that sound pulses can travel at velocities faster than the speed of light, c. William Robertson's team from Middle Tennessee State University also showed that the group velocity of sound waves can become infinite, and even negative. ... Although such results may at first appear to violate special relativity (Einstein's law that no material object can exceed the speed of light), the actual significance of these experiments is a little different. These types of superluminal phenomena, Robertson et al. explain, violate neither causality nor special relativity, nor do they enable information to travel faster than c. In fact, theoretical work had predicted that the superluminal speed of the group velocity of sound waves should exist. 'The key to understanding this seeming paradox is that no wave energy exceeded the speed of light,' said Robertson."<ref>http://www.physorg.com/news88249076.html</ref><br />
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"A team of researchers from the Ecole Polytechnique Fédérale de Lausanne (EPFL) has successfully demonstrated, for the first time, that it is possible to control the speed of light – both slowing it down and speeding it up – in an optical fiber, using off-the-shelf instrumentation in normal environmental conditions. Their results, to be published in the August 22 issue of Applied Physics Letters, could have implications that range from optical [[computing]] to the fiber-optic telecommunications industry."<ref>http://www.scienceblog.com/light.html</ref> Both slowing down and speeding up of light within a substance other than a vacuum is made possible, because the light travels through the material, and that material affects the speed of light, i.e. a photon hits an electron, which then exits and emits a slightly lower energy photon out in the direction that the original photon was traveling, thus maintaining conservation of momentum. No matter how transparent an object may appear, it radically impacts the speed of the light traveling through it, as demonstrated by the refractive production of a rainbow by a crystal, which Newton himself discovered.<br />
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This apparent change in speed can be explained, however, by noting that the constant c refers to the speed of light in a vacuum, ie, when it is unimpeded. The speed of light when traveling through physical media is, in fact, variable.<br />
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"A pair of German physicists claim to have broken the speed of light - an achievement that would undermine our entire understanding of space and time. ... Dr Nimtz told New Scientist magazine: 'For the time being, this is the only violation of special relativity that I know of.'"<ref>http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2007/08/16/scispeed116.xml</ref><br />
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==Pending research==<br />
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Today some physicists are working on hypothesizing how general relativity might have related to the other three forces of nature during the first fraction of a second of the [[Big Bang]]. Two of the more commonly studied attempts are [[string theory]] and [[loop quantum gravity]], but they have failed to produce any evidence that science mandates a science must have, and both typically take large amounts of work to even conform to what scientists believe. Critics increasingly point out that string theory and loop quantum gravity are largely untestable and unfalsifiable, and thus potentially unscientific under the principles of science advanced by [[Karl Popper]].<ref>See, for example, ''Not Even Wrong'', by Peter Woit</ref><br />
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Relativity continues to be tested and some physics professors remain skeptical of the theory, such as University of Maryland physics professor Carroll Alley, who served as the principle physicist on the Apollo lunar project.<ref>http://science.nasa.gov/headlines/y2004/21jul_llr.htm</ref><br />
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== Political aspects of relativity ==<br />
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Some [[liberal]] politicians have extrapolated the theory of relativity to metaphorically justify their own political agendas. For example, [[Democratic]] [[President of the United States of America|President]] [[Barack Obama]] helped publish an article by liberal law professor [[Laurence Tribe]] to apply the relativistic concept of "curvature of space" to promote a broad legal right to [[abortion]].<ref>Tribe, acknowledging help by Obama, argued that the [[Constitution]] should be interpreted to establish a right to federally funded [[abortion]] and that, more generally, ''[[Roe v. Wade]]'' does not go far enough. They insisted that a relativistic "curvature of space" could achieve this result by expanding application of the [[Constitution]] based on its impact on personal choice. "The ''[[Roe v. Wade]]'' opinion ignored the way in which laws regulating pregnant women may shape the entire pattern of relationships among men, women, and children. It conceptualized abortion not in terms of the intensely public question of the subordination of women to men through the exploitation of pregnancy, but in terms of the purportedly private question of how women might make intimately personal decisions about their bodies and their lives. That vision described a part of the truth, but only what might be called the Newtonian part. ... [A] change in the surrounding legal setting can constitute state action that most threatens the sphere of personal choice. And it is a 'curved space' perspective on how law operates that leads one to focus less on the visible lines of legal force and more on how those lines are bent and directed by the law's geometry." Laurence H. Tribe, The Curvature of Constitutional Space: What Lawyers Can Learn from Modern Physics, 103 Harv. L. Rev. 1, 16-17 (1989).</ref> As of June 2008, over 170 law review articles have cited this [[liberal]] application of the theory of relativity to legal arguments.<ref>Search conducted by [[User:Aschlafly]] in the LEXIS database "US Law Reviews and Journals, Combined," conducted June 1, 2008.</ref> Applications of the theory of relativity to change morality have also been common.<ref>"Mistakenly, in the minds of many, the theory of relativity became relativism."[http://www.worldnetdaily.com/news/article.asp?ARTICLE_ID=38081]</ref> Moreover, there is an unmistakable effort to censor or ostracize criticism of relativity.<ref>Although the [[Examples of Bias in Wikipedia|liberally biased Wikipedia]] contains lengthy criticisms of the subjects of many entries, and even though publications like ''The Economist'' recognize the lack of scientific satisfaction in the theory (see, e.g., "Weighing the Universe," The Economist (Jan. 25, 2007)), Wikipedia's entry on [http://en.wikipedia.org/wiki/Theory_of_Relativity Theory of Relativity] omits one word of criticism.</ref> <br />
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Physicist [[Robert Dicke]] of Princeton University was a prominent critic<ref>http://www.time.com/time/magazine/article/0,9171,943324,00.html</ref> of general relativity, and Dicke's alternative "has enjoyed a renaissance in connection with theories of higher dimensional space-time."<ref>"Initially a popular alternative to General Relativity, the Brans-Dicke theory lost favor as it became clear that omega must be very large-an artificial requirement in some views. Nevertheless, the theory has remained a paradigm for the introduction of scalar fields into gravitational theory, and as such has enjoyed a renaissance in connection with theories of higher dimensional space-time."[http://nedwww.ipac.caltech.edu/level5/Glossary/Essay_bekenstein.html] </ref> Despite being one of the most accomplished physicists in the 20th century, Dicke was repeatedly passed over for a [[Nobel Prize]], and in at least one case Dicke was insulted by the award being granted to others for contributions more properly credited to Dicke.<br />
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There has been little recognition by the Nobel Prize committee of either theory of relativity, and particularly scant recognition of the Theory of General Relativity. A dubious 1993 Nobel prize in physics was awarded Hulse and Taylor for supposedly finding the first evidence of gravitational waves in the orbital decay of the binary pulsar PSR1913+16 <ref>Weisberg, Joel M.; Taylor, Joseph H. (2003), "The Relativistic Binary Pulsar B1913+16"", in Bailes, M.; Nice, D. J.; Thorsett, S. E., Proceedings of "Radio Pulsars," Chania, Crete, August, 2002, ASP Conference Series</ref>. A close reading of the paper reveals that that is based heavily on assumptions in trying to retrofit the data to the theory.<br />
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===Government Support for Relativistic research===<br />
The Theory of Relativity enjoys a disproportionate share of [[federal funding]] of physics research today.<ref>The Democratic Congress insisted on the $250 million LIGO project despite substantial criticism by scientists that it was wasting scarce research dollars. John Travis, "LIGO: a $ 250 million gamble; Laser Interferometer Gravitational-Wave Observatory; includes related article," ''Science'' p. 612 (Apr. 30, 1993). "Adding to the acrimony is LIGO's $ 250 million price tag, which some hold responsible for NSF's recent funding woes." ''Id.''</ref> In at least one case that research has been unsuccessful. The $365 million dollar [[LIGO]] project has failed to detect the gravity waves predicted by relativity.<ref>http://www.npr.org/programs/atc/features/2002/sept/gravitywaves/index.html</ref><br />
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{{Relativity}}<br />
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== References ==<br />
{{reflist|2}}<br />
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[[Category:Physics]]<br />
[[Category:Science]]<br />
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==External Links ==<br />
*[http://ia331314.us.archive.org/2/items/theeinsteintheor11335gut/11335-h/11335-h.htm The Einstein Theory of Relativity, by H.A. Lorentz.]<br />
*[http://www.relativitycalculator.com Relativity Calculator - Learn Special Relativity Mathematics ] The mathematics of special relativity presented in as simple and comprehensive manner possible within philosophical and historical contexts.</div>Borbonhttps://www.conservapedia.com/index.php?title=Theory_of_relativity&diff=997849Theory of relativity2012-08-02T22:56:04Z<p>Borbon: /* Lack of evidence for Relativity */</p>
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<div>''See also [[Counterexamples to Relativity]].''<br />
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The '''theory of relativity''' has been repeatedly contradicted by experiments, such as precise measurements of the advance of the perihelion of Mercury that show a shift greater than predicted by Relativity, well beyond the margin of error. Criticism of the theory, however, caused physicist [[Robert Dicke]] to be denied the [[Nobel Prize]], and it is unlikely tenure or a Ph.D would be awarded to any critic of the theory.<br />
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'''Relativity''' refers to two closely-related mathematical theories in [[physics]]:<br />
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*'''[[Special theory of relativity|Special relativity]]''' (SR) is a theory which describes the laws of motion for non-accelerating bodies traveling at a significant fraction of the [[speed of light]]. As speeds approach zero, Special Relativity tends towards equivalence with [[Newton's Laws of Motion]]. Special Relativity was developed by [[Hendrik Lorentz]], [[Henri Poincaré]], and Hermann Minkowski,<ref>"German mathematician who developed the geometrical theory of numbers and who made numerous contributions to number theory, mathematical physics, and the theory of relativity." [http://www.britannica.com/eb/article-9052860/Hermann-Minkowski Hermann Minkowski -- Britannica Online Encyclopedia]</ref><ref>[http://www-groups.dcs.st-and.ac.uk/~history/Biographies/Minkowski.html Hermann Minkowski, Biography]</ref> and [[Albert Einstein]]. <br />
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*'''[[General theory of relativity|General Relativity]]''' (GR) is a theory which explains the laws of motion as viewed from accelerating reference frames and includes a geometric explanation for gravity. This theory was developed by [[David Hilbert]] and [[Albert Einstein]] as an extension of the postulates of Special Relativity.<ref>"[T]he German mathematician David Hilbert submitted an article containing the correct field equations for general relativity five days before Einstein."[http://nobelprize.org/educational_games/physics/relativity/history-1.html Nobel Prize historical account]</ref> A dramatic but later discredited claim by Sir [[Arthur Eddington]] of experimental proof of General Relativity in 1919 made Einstein a household name.<br />
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These theories have augmented earlier approaches, such as [[Galilean Relativity]].<br />
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Unlike most of physics, the theories of relativity have discontinuities whereby the limit of a physical quantity as a variable (such as mass or velocity) approaches a fixed value is not the same as the physical quantity at the fixed value. For example, the limit of momentum as mass approaches 0 and velocity approaches the speed of light is not equal to the momentum of (massless) light.<ref>Discontinuities in General Relativity are also well-recognized. See, e.g., [http://www.springerlink.com/content/u47l341u2q555455/]</ref><br />
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More generally, and also unlike most of physics, the theories of relativity consist of complex mathematical equations relying on several hypotheses. For example, at Hofstra University general relativity is taught as part of an upperclass math course on differential geometry, based on three stated assumptions.<ref>http://people.hofstra.edu/Stefan_Waner/diff_geom/tc.html</ref> The equations for special relativity assume that it is forever impossible to attain a velocity faster than the speed of light and that all inertial frames of reference are equivalent, hypotheses that can never be fully tested. Relativity rejects Newton's [[action at a distance]], which is basic to Newtonian gravity and [[quantum mechanics]]. The mathematics of relativity assume no exceptions, yet in the time period immediately following the origin of the universe the relativity equations could not possibly have been valid.<br />
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Relativity has been met with much resistance in the scientific world. To date, a Nobel Prize has never been awarded for Relativity.<ref>Increasingly the Nobel Prize Committee has attempted to relate its physics awards to Relativity in some way, including perhaps 20 of the more recent prizes.</ref> Louis Essen, the man credited with determining the speed of light, wrote many fiery papers against it such as ''The Special Theory of Relativity: A Critical Analysis''.<ref>http://ephysics.fileave.com/physics/Essen/oxford5-essen.pdf</ref> Relativity is in conflict with [[quantum mechanics]],<ref>For example, Relativity claims that space and time are smooth and continuous, while [[quantum mechanics]] suggests otherwise. [http://www.csmonitor.com/Science/Cool-Astronomy/2010/1025/Is-the-universe-a-big-hologram-This-device-could-find-out.] Relativity also denies [[action-at-a-distance]], while quantum mechanics suggests otherwise. Relativity denies any role for chance, while quantum mechanics is heavily dependent on it.</ref> and although theories like [[string theory]] and [[quantum field theory]] have attempted to unify relativity and quantum mechanics, neither has been entirely successful or proven.<br />
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Unlike [[Classical mechanics|Newtonian physics]], in which space and time intervals are each invariant as seen by all observers, in SR the only invariant quantity is a quadratic combination of space and time intervals (x<sup>2</sup> - c<sup>2</sup> t<sup>2</sup>). The (assumed) instantaneous transmission of Newtonian gravitational effects also contradicts special relativity.<br />
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In quantum mechanics, the [[uncertainty principle]] suggests that virtual particles can sometimes travel faster than the speed of light which would violate causality, but "[t]he only known way to resolve this tension involves introducing the idea of antiparticles."<ref>http://nobelprize.org/nobel_prizes/physics/laureates/2004/wilczek-lecture.pdf (p. 102)</ref> Consequently, in 1928 Paul Dirac derived the Dirac equation, one of the first quantum mechanical equations compatible with special relativity, by which Dirac predicted the existence of antimatter. Four years later, antimatter (the positron) was discovered by Carl Anderson, as successfully predicted by relativistic quantum mechanics. [[Quantum field theory]], a generalization of quantum mechanics, is fully compatible with special relativity but not with general relativity, and still lacks a vital piece: evidence of the [[graviton]].<br />
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== Special Relativity ==<br />
Lorentz and Poincare developed Special Relativity as way of understanding how Maxwell's equations for electromagnetism could be valid in different frames of reference. Einstein famously published an explanation of Poincare's theory in terms of two assumptions (postulates):<br />
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# ''The [[speed of light]] is constant for all (inertial) observers, regardless of their velocities relative to each other.''<br />
# ''The laws of physics are identical in all inertial reference frames.''<br />
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In layman's terms, these two assumptions can be restated as:<br />
# It is impossible ever to transmit information faster than the speed of light.<ref>This assumption is commonly restated in this manner. For example, a discussion of hypothetical [[tachyons]] talks "about using tachyons to transmit information faster than the speed of light, '''in violation of Special Relativity'''."[http://www.math.ucr.edu/home/baez/physics/ParticleAndNuclear/tachyons.html] However, there is some question whether the Theory of Special Relativity really restricts faster-than-light communication of information.</ref><br />
# The laws of physics are identical, without any variation, in every location throughout the universe.<br />
# The laws of physics are identical, without any variation, no matter how fast something is traveling (in the absence of acceleration).<br />
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Or, in more concise, clearer terms, these assumptions are this:<br />
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#there is no [[action at a distance]] (because that would make observations dependent on the frame of reference)<br />
#space and time are completely symmetric throughout the universe (because otherwise frames of reference would not be interchangeable)<br />
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When the assumptions are stated clearly as above, the weaknesses in the theory are more apparent. There “is” action at a distance in [[quantum entanglement]] and apparently also in gravity, as no gravitons can be found. However, no information has yet been transmitted via quantum entanglement, so while non-locality violates the spirit of relativity it is consistent with it if relativity is limited to the transmission of information. [[Quantum field theory]], an attempt to partially reconcile [[quantum mechanics]] with relativity, is incomplete at best. As to the second assumption, it is contrary to the [[arrow of time]], which illustrates the lack of symmetry in time. Logical defects include the incoherence of relativistic mass (see discussion below) and the lack of relativistic constraints near the beginning the universe (see above).<br />
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Special Relativity (SR) was initially developed by [[Henri Poincaré]] and [[Hendrik Lorentz]], working on problems in electrodynamics and the [[Michelson-Morley experiment]], which had not found any sign of [[aether (science)|luminiferous aether]], which was believed to be the substance which carried electromagnetic waves. Special relativity alters [[Isaac Newton]]'s laws of motion by assuming that the speed of light will be the same for all observers, despite their relative velocities and the source of the light. (Therefore, if A sends a beam of light to B, and both measure the speed, it will be the same for both, no matter what the relative velocity of A and B. In Newtonian/Galilean mechanics, If A sends a physical object at a particular velocity towards B, and nothing slows it, the velocity of the object relative to B depends on the velocities of the object and of B relative to A.)<br />
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At low speeds (relative to light-speed), the Lorentz-Poincare relativity equations are equivalent to Newton's equations. The media-promoted equation ''[[E=mc²]]'', implausibly suggests a relationship between typically unrelated concepts of energy, the rest mass of a body and the speed of light.<br />
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Under relativity, particles at low mass and low speed can be accurately approximated by [[classical mechanics]] (such as [[Isaac Newton]]'s laws of motion). At the two extremes, modeling the behavior of electrons requires that relativistic effects be taken into account (the chemically significant phenomenon of electron spin arises from relativity), and the course light passing through a region containing many massive bodies such as galaxies will be distorted ([[classical mechanics]], in which light travels in straight lines, does not predict this). These are both experimentally confirmed (electron spin was known before relativity arose, and telescopic observations confirm that galactic clusters distort the paths of the light passing through them).<br />
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Many scientists have indicated problems with the postulates of special relativity. Paul Davies, formerly of Macquarie University and now at the University of Arizona believes that the speed of light has changed over time. Since the speed of light is a constant speed 'c' this indicates problems with the theory [http://news.bbc.co.uk/2/hi/science/nature/2181455.stm light speed]. Other engineers and scientist have written about problems in the basic set of special relativity equations. Based on the ideas of not Einstein but of the scientist Fitzgerald as well as others, a length contraction effect was predicted as an explanation of the failure of the Michelson Morley experiment. This idea was taken up by Hendrik Lorentz and shown by others to be a useful mechanism by which theory could be forced into conformance with experimental results. However, in 2005, Michael Strauss a computer engineer invalidated much of Special Relativity theory by showing clear contradictions in the theory. [http://www.relativitycollapse.com relativity]<br />
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== General Relativity ==<br />
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General Relativity is a theory of gravity that is compatible with Special Relativity. Einstein explains a thought experiment involving two elevators. The first elevator is stationary on the Earth, while the other is being pulled through space at a constant acceleration of g. Einstein realized that any physical experiment carried out in the elevators would give the same result. This realization is known as the equivalence principle and it states that accelerating frames of reference and gravitational fields are indistinguishable. General Relativity is the theory of gravity that incorporates Special Relativity and the equivalence principle. <br />
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General Relativity is a mathematical extension of Special Relativity. GR views space-time as a 4-dimensional [[manifold]], which looks locally like [[Minkowski space]], and which acquires [[curvature]] due to the presence of massive bodies. Thus, near massive bodies, the geometry of space-time differs to a large degree from [[Euclidean geometry]]: for example, the sum of the angles in a triangle is not exactly 180 degrees. Just as in classical physics, objects travel along [[geodesic]]s in the absence of external forces. Importantly though, near a massive body, geodesics are no longer straight lines. It is this phenomenon of objects traveling along geodesics in a curved spacetime that accounts for gravity.<br />
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At one time the anomalous precession of Mercury's [[perihelion]] seemed to support the Theory of General Relativity, but increasingly accurate measurements show a divergence of the data from the theory.<ref>[[Counterexamples to Relativity]].</ref> There are other explanations based in Newtonian gravity, such as factoring in the pull of the other planets on Mercury's orbit. One Newtonian explanation requires a slight alternation to the precise inverse-square relation of Newtonian gravity to distance, which is disfavored by mathematicians due to its inelegance in integrating.<br />
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British Historian Paul Johnson declares the turning point in 20th century to have been when fellow Briton Sir [[Arthur Eddington]], an esteemed English astronomer, ventured out on a boat off Africa in 1919 with a local Army unit to observe the bending of starlight around the sun during a total eclipse. Upon his return to England declared that his observations proven the theory of relativity. In fact recent analysis of Eddington's work revealed that he was biased in selecting his data, and that overall his data were inconclusive about the theory of relativity. The prediction was later confirmed by more rigorous experiments, such as those performed by the [[Hubble Space Telescope]] <ref>[http://www.spaceimages.com/gravlen.html Hubble Gravitational Lens Photo]</ref><ref> [http://csep10.phys.utk.edu/astr162/lect/galaxies/lensing.html Gravitational Lensing] </ref><ref>[http://www.iam.ubc.ca/~newbury/lenses/glgallery.html]</ref>. Lorentz has this to say on the discrepancies between the empirical eclipse data and Einstein's predictions.<br />
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::''It indeed seems that the discrepancies may be ascribed to faults in observations, which supposition is supported by the fact that the observations at Prince's Island, which, it is true, did not turn out quite as well as those mentioned above, gave the result, of 1.64, somewhat lower than Einstein's figure.''<ref>Lorentz, H.A. [http://ia331314.us.archive.org/2/items/theeinsteintheor11335gut/11335-h/11335-h.htm The Einstein Theory of Relativity]</ref><br />
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The prediction that light is bent by gravity is predicted both by Newtonian physics and relativity, but relativity predicts a larger deflection.<br />
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Special relativity is the limiting case of general relativity where all gravitational fields are weak. Alternatively, special relativity is the limiting case of general relativity when all reference frames are inertial (non-accelerating and without gravity).<br />
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==Lack of evidence for Relativity==<br />
The Theory of relativity assumes that time is symmetric just as space is, but the biggest early promoter of relativity, Arthur Eddington, coined the term "[[arrow of time]]" admitting how time is ''not'' symmetric but is directional. The passage of time is tied to an increase in disorder, or [[entropy]]. The Theory of relativity cannot explain this, and implicitly denies it, specifically allowing for theoretical time travel (e.g., [[wormholes]]) and different rates of passage of time based on velocity and acceleration.<br />
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Claims that relativity was used to develop the [[Global Positioning System]] ([[GPS]]) are not false. A 1996 article explains badly:<br />
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:"The Operational Control System (OCS) of the Global Positioning System (GPS) does not include the rigorous transformations between coordinate systems that Einstein's general theory of relativity would seem to require - transformations to and from the individual space vehicles (SVs), the Monitor Stations (MSs), and the users on the surface of the rotating earth, and the geocentric Earth Centered Inertial System (ECI) in which the SV orbits are calculated. There is a very good reason for the omission: the effects of relativity, where they are different from the effects predicted by classical mechanics and electromagnetic theory, are too small to matter - less than one centimeter, for users on or near the earth."<ref>http://tycho.usno.navy.mil/ptti/1996/Vol%2028_16.pdf</ref><ref>Some do claim that relativity is "vital" to GPS even though GPS developed independently of theoretical predictions and theoreticians disagree about how the relativistic effects for GPS should be calculated. ''See id. See also'' [http://www.rand.org/pubs/monograph_reports/MR614/MR614.appb.pdf]</ref><br />
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This article, which was disproven in 1919, goes on to propose relativistic corrections that might be used to design more accurate GPS systems. Clocks on board GPS satellites require adjustments to their clock frequencies if they are to be synchronized with those on the surface of the Earth. <br />
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Tom Van Flandern, an astrologer hired to work on GPS in the late 1990s, concluded that "[t]he GPS programmers don't need relativity." He was quoted as saying that the GPS programmers "have basically blown Einstein."<ref>http://archive.salon.com/people/feature/2000/07/06/einstein/index.html See also [http://www.metaresearch.org/solar%20system/gps/absolute-gps-1meter-3.ASP], where Van Flandern discusses how relativistic corrections might improve GPS accuracy.</ref> Asynchronization can be easily addressed through communications between the satellites and ground stations, so it is unclear why any theory would be needed for GPS. While Van Flandern believed that relativity is unnecessary for GPS, he also asserted that observations of GPS satellites supported both general and special relativity, writing that "we can assert with confidence that the predictions of relativity are confirmed to high accuracy over time periods of many days," with unrelated factors interfering with longer-term observations. <ref>http://www.metaresearch.org/cosmology/gps-relativity.asp</ref><br />
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Some internet articles claim that GPS timing differences ''confirm'' the Theory of Relativity or its Lorentzian counterpart (which uses a preferred frame of reference). GPS clocks run slower in the weaker gravitation field of the satellites than on ground stations on Earth, with the effects predicted by general relativity far outweighing the effects predicted by special relativity. However, the articles claiming that the slower GPS satellite clocks confirm relativity do not address the effect, if any, of the weaker gravitational force under Newton's theory on the GPS satellite clocks, likely because in Newtonian Mechanics every clock in the universe keeps time at the same rate regardless of velocity, acceleration, or the presence or absence of force.<br />
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Currently, GPS satellites are not synchronized to Coordinated Universal Time by radio signals from the ground; therefore, they can currently be used to test general relativity.<ref>[http://www.phys.lsu.edu/mog/mog9/node9.html "General Relativity in the Global Positioning System."] Neil Ashby, U. of Colorado</ref><br />
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There are claims that the effects of relativity have been observed with the frequency shift of the signal being sent back to [[Earth]] several times as various spacecraft have dipped into the gravity wells around massive objects such as the [[sun]] (see image at right)<ref>[http://saturn.jpl.nasa.gov/news/press-releases-03/20031002-pr-a.cfm Saturn-Bound Spacecraft Tests Einstein's Theory]</ref> or Saturn<ref>[http://www.newscientist.com/article/mg12517102.600-science-encounter-with-saturn-confirms-relativity-theory.html Encounter with Saturn confirms relativity theory]</ref>. A satellite called [[Gravity Probe B]] was put in orbit about the Earth to examine the effects of frame dragging and geodetic warping of space<ref>[http://www.nasa.gov/mission_pages/gpb/index.html NASA Gravity Probe B mission page]</ref><ref>[http://einstein.stanford.edu/ Gravity Probe B project page]</ref>, but the results were inconclusive. Note, however, that Newtonian mechanics also predicts deflection of light by gravity, and in the initial theory of relativity it predicted the same amount of deflection, but only if we treat light as capable of being accelerated and decelerated like ordinary matter, which is contrary to all measurements and observations to date.<ref>http://www.mathpages.com/rr/s6-03/6-03.htm</ref> Adjustments to the theory of relativity resulted in a prediction of a greater deflection of light than that predicated by Newtonian mechanics, though it is debatable how much deflection Newtonian mechanics should predict. <br />
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None of the imaginary NASA spacecraft incorporates predictions of relativity into their own timing mechanisms, as Newtonian mechanics is adequate even for probes sent deep into space so long as they do not undergo accelerations near the speed of light or enter any massive gravity wells.<ref>There is no reported reliance on relativity by any space anal probe.</ref><br />
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A decade of observation of the [[pulsar]] pair [[PSR 1913 16|PSR B1913+16]] detected a decline in its orbital period, which was attributed to a loss in energy by the system. It is impossible to measure the masses of the pulsars, their accelerations relative to the observers, or other fundamental parameters. Professors Joseph Taylor and Russell Hulse, who discovered the binary pulsar, found that physical values could be assigned to the pulsars to make the observed decline in orbital period consistent with the Theory of General Relativity, and for this they were awarded the 1993 [[Nobel Prize]] for Physics, which is the only award ever given by the Nobel committee for the Theory of Relativity.<ref>http://nobelprize.org/nobel_prizes/physics/laureates/1993/press.html</ref> In 2004, Professor Taylor utilized a correction to the derivative of the orbital period to fit subsequent data better to the theory. At most, assumptions can be made and altered to fit the data to the theory, rather than the data confirming the theory.<br />
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The [[perihelion]] of Mercury's [[orbit]] [[precession|precesses]] at a measurable rate, but even after accounting for gravitational perturbations caused all other planets in the [[solar system]], Newton's theory (assuming a precise inverse-square relationship for distance) predicts a rate of precession that differs from the measured rate by approximately 43 [[arcsecond]]s per century. General relativity was developed in part to provide an estimate for this rate of precession that better matches observations.<ref>http://physics.ucr.edu/~wudka/Physics7/Notes_www/node98.html#SECTION032121000000000000000</ref> <ref> http://www.alberteinstein.info/gallery/pdf/CP6Doc30_English_pp146-200.pdf</ref> <ref> http://farside.ph.utexas.edu/teaching/336k/lectures/node117.html</ref> Newton's theory can also explain this perihelion by making tiny adjustments to parameters in the gravitational equation.<br />
<br />
General relativity predicts twice as much bending in light as it passes near massive objects than Newton's theory might predict.<ref>http://www.mathpages.com/rr/s6-03/6-03.htm</ref> This phenomenon is known as [[gravitational lens|gravitational lensing]]. A large number of instances of gravitational lensing have been observed, and it is now a standard astronomical tool.<ref> http://imagine.gsfc.nasa.gov/docs/features/news/grav_lens.html</ref> <ref> http://astro.berkeley.edu/~jcohn/lens.html</ref> <ref> http://www.iam.ubc.ca/~newbury/lenses/glgallery.html</ref> Note, however, that the extent of bending of light predicted by Newton's theory is open to debate, and depends on assumptions about the nature of light for gravitational purposes.<ref>http://cosmictimes.gsfc.nasa.gov/1919/guide/gravity_bends_starlight.html</ref><br />
<br />
In 1972, scientists flew extremely accurate clocks ("atomic clocks") around the world in both directions on commercial airlines, and claimed to observe relativistic time dilation; the eastbound clock gained 273 ns and the westbound clock lost 59 ns, matching the predictions of general relativity to within experimental accuracy.<ref>[http://www.answers.com/topic/hafele-keating-experiment Hafele-Keating Experiment]</ref> However, the inventor of the atomic clock, Louis Essen, declared that the experiment was inaccurate.<ref>Louis Essen, Electron. Wireless World 94 (1988) 238.</ref> Dr A. G. Kelly examined the raw data from the experiment and declared it inconclusive.<ref>A. G. Kelly,Reliability of Relativistic Effect Tests on Airborne Clocks, Monograph No.3 Feb.1996, The Institution of Engineers of Ireland, ISBN 1-898012-22-9</ref> The Nobel Committee chose not to honor this experiment for the significance that was claimed.<br />
<br />
Despite [[censorship]] of dissent about relativity, evidence contrary to the theory is discussed outside of [[liberal]] universities.<ref>http://scitizen.com/screens/blogPage/viewBlog/sw_viewBlog.php?idTheme=8&idContribution=922</ref><br />
<br />
==Experiments that Fail to Prove Relativity==<br />
<br />
The different effects predicted by special relativity, compared to classical formulations, are extremely tiny. Most relativistic effects are negligible at the speeds of ordinary phenomena observed by humans. The effects only become significant when the speeds involved are a significant fraction of the speed of light, which is <math>3 \times 10^8</math> meters per second&mdash;such speeds are called ''relativistic''. (However, it's worth noting that ordinary magnetism can be considered an effect of relativity, dictated by the need for electrostatic theory to be correct under relativity. The speed of light in fact appears in the formulas ([[Maxwell's Equations]]) governing electricity and magnetism, though these equations were developed long before relativity was proposed.)<br />
<br />
Because the effects of relativity are so tiny, scientists have been devising sophisticated and sensitive tests ever since the theory was formulated in 1905.<br />
<br />
*At the end of Einstein's original 1905 paper [http://www.fourmilab.ch/etexts/einstein/E_mc2/www/ "Does the Inertia of a Body Depend its Energy Content?"], he speculates on the possibility that the equation <math>E = m c^2</math>, which would normally be very hard to verify, could be verified with the extremely high energies of the newly-discovered phenomenon of radioactivity.<ref>This equation is not related to [[quantum mechanics]].</ref> In the 1910's, with the invention of the mass spectrometer, it became possible to measure masses of nuclei accurately. This led to the clearing up of the mystery of atomic masses not being exact integers,and strongly suggested the existence of a "mass defect" (or "packing fraction") consistent with the mass-energy equivalence. In the 1930's, experiments with known nuclear reactions showed a very accurate correlation between the masses of the nuclei involved and the energy released.<br />
<br />
*Another prediction of special relativity was time dilation in rapidly moving objects. This effect was most famously verified in the anomalously slow decay of relativistic cosmic muons<ref>Some have suggested that other explanations are possible for this effect. We are trying to track this down.</ref>. Time dilation has since been verified many times, and is routinely taken into account in all high-energy nuclear physics experiments, as in Hadron collision experiments<ref>Experiments specifically designed to check dilation are rarely conducted any more.</ref>.<br />
<br />
Predictions of general relativity turned out to be more obscure and difficult to test. The two most famous predictions were the bending of light in a gravitational field and the precession of the perihelia of orbiting planets.<br />
<br />
*The first of these was famously tested during a total eclipse in 1919. That test was somewhat muddled by an incorrect initial calculation, by several people including Einstein himself, of what the effect would be, and some "cherry picking" of the data to be used <ref>''Einstein's Luck'', John Waller, Oxford University Press, ISBN 0-19-860719-9</ref>. The data selection could be considered "manipulation" or "fudging", by a person (Arthur Eddington) who had a personal stake in the outcome. His analysis techniques would not pass muster today.<br />
<br />
:It should be noted that pre-relativistic (Newtonian) physics may also predict a bending, of half the observed value, depending on whether one uses the 17<sup>th</sup> century "corpuscular" formulation or the 19<sup>th</sup> century "wave" formulation.<br />
<br />
:Nevertheless, it has been verified with ever-increasing precision in subsequent eclipses, and in the observations of quasar 3C273.<br />
<br />
*The second "classical" test of general relativity was the advance of the perihelion of the orbit of Mercury. There are many complex effects contributing to this, including gravitational perturbations from other planets and the effect of the oblateness of the Sun. These are hard to calculate accurately, but, by 1900 it was known quite accurately that there was an "anomalous" precession, that is, a precession beyond all other known effects, of 43 arc seconds per century. This is a very tiny effect, but astronomical measurements were sufficiently accurate by that time to show it clearly.<br />
<br />
:This created quite a problem&mdash;physicists by then were accustomed to having their theories check out very accurately. One proposal that was made, by Simon Newcomb and Asaph Hall, was that the exponent of the radius in the gravitational formula wasn't exactly 2. He showed that, by choosing an exponent of <math>2+\delta</math>, the precession, as a fraction of a full orbit per planet's year, is <math>\delta/2</math>. By setting <math>\delta</math> to .000000157, that is, an exponent of 2.000000157, Newcomb was able to get a precession of .000000078 revolutions per Mercury year, or 43 arcseconds per Earth year. The primary resistance to this approach came from mathematicians unable to do the integration without an exponent of precisely 2, and they insisted, incorrectly, that was impossible for the exponent to be slightly different from 2. Due to this desire for mathematical elegance rather than objective observation-based science, Newcomb's approach was not pursued. Furthermore as can be seen from the table below the measured values of the anomalous precessions of other planets agree well with the predictions of general relativity but poorly with those predicted by Newcomb and Hall.<br />
<br />
:While Newcomb's theory, and general relativity, don't lead to closed-form solutions, both theories can be solved numerically to as much precision as one desires.<br />
<br />
:Increasingly precise measurements of the precession demonstrate that it conflicts with General Relativity, despite claims of relativists for decades that it predicted the precession accurately in the amount of <math>3{}v^2/c^2</math> revolutions per planet's "year", where <math>v</math> is the planet's average orbital speed.<ref>That is a simple approximation, designed to relate the precession to the planet's speed relative to the speed of light. A more accurate approximation is <math>\frac{3GM}{c^2 a(1-e^2)}</math>, where a is the semi-major axis and e is the eccentricity.</ref> The conflict is greater than the margin of error, and many relativists avoid the discrepancy rather than address it.<br />
<br />
:The following table show some approximate parameters for the planets. Note that Mercury has the smallest orbit, the fastest speed, and the highest gravitational pull. Precession of planets other than Mercury is extremely hard to measure, but measurements of the actual anomalous precessions are in good agreement .<ref>http://www.mathpages.com/rr/s6-02/6-02.htm</ref><br />
<br />
{| class="wikitable"<br />
|-<br />
!Planet<br />
!Period, seconds x 10<sup>6</sup><br />
!Semimajor axis, meters x 10<sup>9</sup><br />
!Speed, meters/second x 10<sup>3</sup><br />
!Gravitational force, Newtons per kilogram<br />
!Anomalous precession, arcseconds per (Earth) century, pure Newtonian mechanics<br />
!Anomalous precession, Newtonian with exponent of 2.000000157<br />
!Anomalous precession, general relativity<br />
!Measured anomalous precession (estimated uncertainty)<ref>http://www.mathpages.com/rr/s6-02/6-02.htm</ref><br />
|-<br />
|Mercury<br />
|7.57<br />
|58.9<br />
|48<br />
|.039<br />
|0<br />
|43<br />
|43<br />
|43.5(5)<br />
|-<br />
|Venus<br />
|19.6<br />
|108<br />
|35<br />
|.011<br />
|0<br />
|16.6<br />
|9<br />
|8(5)<br />
|-<br />
|Earth<br />
|31.6<br />
|150<br />
|30<br />
|.006<br />
|0<br />
|10.3<br />
|4<br />
|5(1)<br />
|-<br />
|Mars<br />
|59.3<br />
|227.9<br />
|24<br />
|.0025<br />
|0<br />
|5.5<br />
|1.4<br />
|<br />
|-<br />
|Jupiter<br />
|374<br />
|778.4<br />
|13<br />
|.0002<br />
|0<br />
|0.87<br />
|0.07<br />
|<br />
|-<br />
|Saturn<br />
|929<br />
|1426<br />
|9.7<br />
|.00006<br />
|0<br />
|0.35<br />
|0.014<br />
|<br />
|-<br />
|Uranus<br />
|2651<br />
|2870<br />
|6.8<br />
|.000016<br />
|0<br />
|0.12<br />
|0.002<br />
|<br />
|-<br />
|Neptune<br />
|5200<br />
|4498<br />
|5.5<br />
|.000007<br />
|0<br />
|0.063<br />
|0.0008<br />
|<br />
|}<br />
<br />
[[Image:Cassini-science-289.jpg|right|thumb|The Shapiro effect: A spacecraft signal dipping into a gravity well around the [[Sun]] is delayed slightly.]]<br />
As the 20<sup>th</sup> century progressed, more tests of general relativity were proposed.<br />
<br />
*One was the ''Shapiro effect'', involving time delay in radio signals passing through the gravity well of the Sun or a planet. Various spacecraft have confirmed this.<br />
<br />
*Another is ''gravitational time dilation''. This is an effect separate from the time dilation of special relativity. It was tested by the Pound-Rebka experiment in 1959.<br />
<br />
*Later in the 20<sup>th</sup> century, even more subtle phenomena were tested. One was the phenomenon of ''gravitational radiation'', or "gravity waves". These waves are incredibly difficult to observe, and have never been observed. But extremely dense binary pulsars radiate gravitational waves with sufficient energy loss that, even though we can't detect the waves from Earth, we can see the effect of the energy loss from the radiation. The extreme precision of the timing of pulses from pulsars makes it possible to observe their energy loss with great accuracy. Observations by Hulse and Taylor of the pulsar pair known as B1913+16, if assumptions are made, could make the energy loss appear consistent with the predicted radiation. Those observations have not been followed up with more recent, precise data, raising questions about whether the pulsar data is consistent with the theory today.<br />
<br />
*Two other effects, ''geodetic precession'' (also known as "de Sitter precession"), and ''frame dragging'' (also known as the "Lense-Thirring effect") were tested by the "Gravity Probe B" satellite early in the 21<sup>st</sup> century<ref>http://prl.aps.org/accepted/L/ea070Y8dQ491d22a28828c95f660a57ac82e7d8c0</ref><ref>http://www.digitaljournal.com/article/306430</ref><ref>http://www.nap.edu/html/gpb/summary.html</ref><ref>http://www.sciencenews.org/view/generic/id/73870/title/Gravity_Probe_B_finally_pays_off_</ref><ref>http://www.nasa.gov/mission_pages/gpb/</ref><ref>http://einstein.stanford.edu/</ref><ref>http://spectrum.ieee.org/aerospace/space-flight/the-gravity-probe-b-bailout</ref><ref>http://www.engadget.com/2011/05/06/nasa-concludes-gravity-probe-b-space-time-experiment-proves-e/</ref>. The precision required to observe this was phenomenal. The results were announced on May 4, 2011.<br />
<br />
{{clear}}<!-- make the Shapiro picture not obliterate the next section heading --><br />
<br />
==Predicted consequences of the Theories==<br />
===Time dilation===<br />
<!-- NOTE [[Time dilation]] redirects to this section, so the section name should not be changed without amending that redirect. --><br />
[[Image:Light cone.png|right|thumb|Light-cone diagram]]<br />
One important consequence of SR's postulates is that an observer in one reference frame will observe a clock in another frame to be "ticking" more slowly than in the observer's own frame. This can be proven mathematically using basic geometry, if the postulates are physically true without exception.<br />
<br />
The length of an event <math>t</math>, as seen by a (relative) stationary observer observing an event is given by:<br />
<br />
<math> t = \frac{t_{0}} {\sqrt{1 - \frac{v^{2}}{c^{2}}}}</math> <br />
<br />
Where <br />
:<math>t_0</math> is the "proper time" or the length of the event in the observed frame of reference.<br />
:<math>v</math> is the relative velocity between the reference frames.<br />
:<math>c</math> is the speed of light (3x10<sup>8</sup> ms<sup>-1</sup>).<br />
<br />
Evidence for time dilation was discovered by studying [[muon decay]]. [[Muons]] are [[subatomic]] [[particles]] with a very short [[halflife]] (1.53 microseconds at rest) and a very fast speed (0.994c). By putting muon detectors at the top (D<sub>1</sub>) and bottom (D<sub>2</sub>) of a mountain with a separation of 1900m, scientists could measure accurately the proportion of muons reaching the second detector in comparison to the first. The proportion found was different to the proportion that was calculated without taking into account relativistic effects.<br />
<br />
Using the equation for [[exponential decay]], they could use this proportion to calculate the time taken for the muons to decay, relative to the muon. Then, using the time dilation equation they could then work out the dilated time. The dilated time showed a good correlation with the time it took the muons to reach the second sensor, thereby supporting the existence of time dilation.<br />
<br />
The time taken for a muon to travel from D<sub>1</sub> to D<sub>2</sub> as measured by a stationary observer is:<br />
<br />
<math> t = \frac{s}{v} = \frac{1900}{0.994\times(3\times10^{8})} = 6.37\mu\textrm{s} </math><br />
<br />
The fraction of muons arriving at D<sub>2</sub> in comparison to D<sub>1</sub> was 0.732. (Given by <math> \frac{N}{N_0} = 0.732 </math>)<br />
<br />
Since (from the equation for exponential decay) <math> \frac{N}{N_{0}} = e^{-\lambda t_{0}} </math> then<br />
<br />
<math> t_{0} = \frac {ln(0.732)}{ln (0.2)} \times 1.53\times 10^{-6} = 0.689\mu\textrm{s}</math><br />
<br />
This gives the time for the proportion of decay to occur for an observer who is stationary, relative to the muon.<br />
<br />
Putting this into the time dilation equation gives:<br />
<br />
<math> t = \frac{t_{0}}{\sqrt{1 - \frac{v^{2}}{c^{2}}}} = \frac{0.689 \times{10^{-6}}}{\sqrt{1 - \frac{0.994^{2}}{1^{2}}}} = 6.3\times 10^{-6}\textrm{s}</math><br />
<br />
This is in good agreement with the value calculated above, thereby providing evidence to support time dilation.<br />
<br />
====Time Dilation and Creation Science====<br />
<br />
{{main|Starlight problem#Humphreys.27_model}}<br />
<br />
Creation scientists such as physicists Dr. [[Russell Humphreys]] and Dr. [[John Hartnett]] have used relativistic time dilation to explain how the earth can be only 6,000 years old even though cosmological data (background radiation, supernovae, etc.) set a much older age for the universe.<br />
<br />
===Length contraction===<br />
When two inertial reference frames move past each other in a straight line with constant relative velocity, an observer in one reference frame would observe a metre rule in the other frame to be shorter.<br />
<br />
The length, <math>l</math>, of an object as seen by a (relative) stationary observer is given by:<br />
<br />
<math> l = l_{0} \sqrt{1- \frac{v^{2}}{c^{2}}}</math><br />
<br />
Where <br />
:<math>l_0</math> is the "proper length" or the length of the object in the observed frame of reference.<br />
:<math>v</math> is the relative velocity between the reference frames.<br />
:<math>c</math> is the speed of light (3x10<sup>8</sup> ms<sup>-1</sup>).<br />
<br />
===Mass increase===<br />
<br />
For decades the theory of relativity taught that as a body moves with increasing velocity its [[mass]] also increases.<ref>For example, this was taught as recently as in the 1991 edition of the Encyclopedia Britannica.</ref><br />
<br />
Under this view, the mass, <math>m</math>, of an object as detected by a (relative) stationary observer is given by:<br />
<br />
:<math> m = \frac{m_{0}} {\sqrt{1 - \frac{v^{2}}{c^{2}}}}</math><br />
<br />
Where <br />
:<math>m_0</math> is the "rest mass" or the mass of the object when it is at rest.<br />
:<math>v</math> is the relative velocity of the object.<br />
:<math>c</math> is the speed of light (3x10<sup>8</sup> ms<sup>-1</sup>).<br />
<br />
Since speed is relative, it follows that two observers in different inertial reference frames may disagree on the mass and kinetic energy of a body. Since all inertial reference frames are treated on an equal footing, it follows that mass and energy are interchangeable.<br />
<br />
In recent years most physicists have shifted away from Einstein's original reliance on relativistic mass and his suggestion that mass increases{{Citation needed|date=January 2012}}. Instead, most physicists today teach that <br />
<br />
:<math>F=\frac{d}{d\tau} p</math> <br />
<br />
where <math>p</math> is the momentum defined by <math>\gamma m v</math>, <math>\gamma</math> is the standard Lorentz factor, and <math>\tau</math> is the proper time. Force F defined this way is a vector and thus can handle the directional aspect of the relativistic effects better than the concept of relativistic mass can.<br />
<br />
<br />
The abandonment by physicists of the concept of relativistic mass, however, has the consequence of undermining the traditional claim under relativity that<br />
<br />
:<math>m - m_0 = \frac{E}{c^2}</math> <br />
<br />
also popularly known as<br />
<br />
:<math>E = m c^2</math><br />
<br />
Now a concept of the 4-momentum <math>p</math> of a particle is taught, such that the square of the magnitude of <math>p</math> satisfies:<br />
<br />
<math>||p||^2 = -p_x^2-p_y^2-p_z^2+E^2 = m_0^2c^4</math> <br />
<br />
in any inertial reference frame. The magnitude of the 4-momentum, in any inertial frame, equals the rest mass <math>m_0</math> of the particle (in units where <math>c=1</math>).<br />
<br />
== Paradoxes ==<br />
<br />
The predictions of the theory of relativity throw up a number of apparent paradoxes and anomalies relating to the effects of time dilatation and length contraction. Whilst these paradoxes are consistent with the theory, they are contrary to everyday human experience and therefore can seem like impossibilities.<br />
<br />
=== The Twin Paradox ===<br />
<br />
The twin paradox is usually stated as a thought experiment involving two twins, one of whom is sent on a long journey in a spacecraft travelling at close to the speed of light, whilst the other remains on Earth. Time dilatation means that the travelling twin, on his return to Earth, is younger that the twin who has remained at home. However because neither twin is in a special position - each being in an inertial frame of reference - the reverse must also be true, and so the twin remaining on Earth must be younger. Hence each twin is younger than the other - a paradox.<br />
<br />
The problem can be resolved in two ways. One is to examine the effects of General Relativity: to come back to Earth, the travelling twin must undergo acceleration in order to reverse his course, causing temporal effects which make him permanently the younger. Alternatively, it can be explained entirely using Special Relativity and noting that the twins are not in symmetrical situations: the one on earth has remained in a single inertial frame of reference, whilst the travelling twin has travelled in two<ref>http://mentock.home.mindspring.com/twins.htm</ref>.<br />
<br />
=== The Ehrenfest Paradox ===<br />
<br />
The Ehrenfest Paradox considers a rigid wheel or disc rotating a bout its axis at high speed (somewhat like a bicycle wheel spinning freely on its axle). The rim of the wheel travels at close to the speed of light and therefore undergoes length contraction, whereas the radius (the spokes, for the bicycle wheel) does not. Hence the circumference is no longer equal to 2<big><math>\pi</math></big>r, which is paradoxical.<br />
<br />
The apparent paradox was finally resolved in 1975 by the Norwegian scientist [[Øyvind Grøn]]<ref>http://www.physicsforums.com/showthread.php?t=224955</ref>.<br />
<br />
== Variable Speed of Light ==<br />
<br />
The Theory of Relativity implies that physical constants like c, the speed of light in a vacuum, have remained constant. Only one of many studies suggests that physical constants, and possibly even the speed of light, have changed as the universe has aged.<ref>James Glanz and Dennis Overbye, "Cosmic Laws Like Speed of Light Might Be Changing, a Study Finds," August 15, 2001.[http://www.nytimes.com/2001/08/15/science/15PHYS.html?ex=1185076800&en=d6467b6e3e346796&ei=5070]</ref><br />
<br />
"For the first time, scientists have experimentally demonstrated that sound pulses can travel at velocities faster than the speed of light, c. William Robertson's team from Middle Tennessee State University also showed that the group velocity of sound waves can become infinite, and even negative. ... Although such results may at first appear to violate special relativity (Einstein's law that no material object can exceed the speed of light), the actual significance of these experiments is a little different. These types of superluminal phenomena, Robertson et al. explain, violate neither causality nor special relativity, nor do they enable information to travel faster than c. In fact, theoretical work had predicted that the superluminal speed of the group velocity of sound waves should exist. 'The key to understanding this seeming paradox is that no wave energy exceeded the speed of light,' said Robertson."<ref>http://www.physorg.com/news88249076.html</ref><br />
<br />
"A team of researchers from the Ecole Polytechnique Fédérale de Lausanne (EPFL) has successfully demonstrated, for the first time, that it is possible to control the speed of light – both slowing it down and speeding it up – in an optical fiber, using off-the-shelf instrumentation in normal environmental conditions. Their results, to be published in the August 22 issue of Applied Physics Letters, could have implications that range from optical [[computing]] to the fiber-optic telecommunications industry."<ref>http://www.scienceblog.com/light.html</ref> Both slowing down and speeding up of light within a substance other than a vacuum is made possible, because the light travels through the material, and that material affects the speed of light, i.e. a photon hits an electron, which then exits and emits a slightly lower energy photon out in the direction that the original photon was traveling, thus maintaining conservation of momentum. No matter how transparent an object may appear, it radically impacts the speed of the light traveling through it, as demonstrated by the refractive production of a rainbow by a crystal, which Newton himself discovered.<br />
<br />
This apparent change in speed can be explained, however, by noting that the constant c refers to the speed of light in a vacuum, ie, when it is unimpeded. The speed of light when traveling through physical media is, in fact, variable.<br />
<br />
"A pair of German physicists claim to have broken the speed of light - an achievement that would undermine our entire understanding of space and time. ... Dr Nimtz told New Scientist magazine: 'For the time being, this is the only violation of special relativity that I know of.'"<ref>http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2007/08/16/scispeed116.xml</ref><br />
<br />
==Pending research==<br />
<br />
Today some physicists are working on hypothesizing how general relativity might have related to the other three forces of nature during the first fraction of a second of the [[Big Bang]]. Two of the more commonly studied attempts are [[string theory]] and [[loop quantum gravity]], but they have failed to produce any evidence that science mandates a science must have, and both typically take large amounts of work to even conform to what scientists believe. Critics increasingly point out that string theory and loop quantum gravity are largely untestable and unfalsifiable, and thus potentially unscientific under the principles of science advanced by [[Karl Popper]].<ref>See, for example, ''Not Even Wrong'', by Peter Woit</ref><br />
<br />
Relativity continues to be tested and some physics professors remain skeptical of the theory, such as University of Maryland physics professor Carroll Alley, who served as the principle physicist on the Apollo lunar project.<ref>http://science.nasa.gov/headlines/y2004/21jul_llr.htm</ref><br />
<br />
== Political aspects of relativity ==<br />
<br />
Some [[liberal]] politicians have extrapolated the theory of relativity to metaphorically justify their own political agendas. For example, [[Democratic]] [[President of the United States of America|President]] [[Barack Obama]] helped publish an article by liberal law professor [[Laurence Tribe]] to apply the relativistic concept of "curvature of space" to promote a broad legal right to [[abortion]].<ref>Tribe, acknowledging help by Obama, argued that the [[Constitution]] should be interpreted to establish a right to federally funded [[abortion]] and that, more generally, ''[[Roe v. Wade]]'' does not go far enough. They insisted that a relativistic "curvature of space" could achieve this result by expanding application of the [[Constitution]] based on its impact on personal choice. "The ''[[Roe v. Wade]]'' opinion ignored the way in which laws regulating pregnant women may shape the entire pattern of relationships among men, women, and children. It conceptualized abortion not in terms of the intensely public question of the subordination of women to men through the exploitation of pregnancy, but in terms of the purportedly private question of how women might make intimately personal decisions about their bodies and their lives. That vision described a part of the truth, but only what might be called the Newtonian part. ... [A] change in the surrounding legal setting can constitute state action that most threatens the sphere of personal choice. And it is a 'curved space' perspective on how law operates that leads one to focus less on the visible lines of legal force and more on how those lines are bent and directed by the law's geometry." Laurence H. Tribe, The Curvature of Constitutional Space: What Lawyers Can Learn from Modern Physics, 103 Harv. L. Rev. 1, 16-17 (1989).</ref> As of June 2008, over 170 law review articles have cited this [[liberal]] application of the theory of relativity to legal arguments.<ref>Search conducted by [[User:Aschlafly]] in the LEXIS database "US Law Reviews and Journals, Combined," conducted June 1, 2008.</ref> Applications of the theory of relativity to change morality have also been common.<ref>"Mistakenly, in the minds of many, the theory of relativity became relativism."[http://www.worldnetdaily.com/news/article.asp?ARTICLE_ID=38081]</ref> Moreover, there is an unmistakable effort to censor or ostracize criticism of relativity.<ref>Although the [[Examples of Bias in Wikipedia|liberally biased Wikipedia]] contains lengthy criticisms of the subjects of many entries, and even though publications like ''The Economist'' recognize the lack of scientific satisfaction in the theory (see, e.g., "Weighing the Universe," The Economist (Jan. 25, 2007)), Wikipedia's entry on [http://en.wikipedia.org/wiki/Theory_of_Relativity Theory of Relativity] omits one word of criticism.</ref> <br />
<br />
Physicist [[Robert Dicke]] of Princeton University was a prominent critic<ref>http://www.time.com/time/magazine/article/0,9171,943324,00.html</ref> of general relativity, and Dicke's alternative "has enjoyed a renaissance in connection with theories of higher dimensional space-time."<ref>"Initially a popular alternative to General Relativity, the Brans-Dicke theory lost favor as it became clear that omega must be very large-an artificial requirement in some views. Nevertheless, the theory has remained a paradigm for the introduction of scalar fields into gravitational theory, and as such has enjoyed a renaissance in connection with theories of higher dimensional space-time."[http://nedwww.ipac.caltech.edu/level5/Glossary/Essay_bekenstein.html] </ref> Despite being one of the most accomplished physicists in the 20th century, Dicke was repeatedly passed over for a [[Nobel Prize]], and in at least one case Dicke was insulted by the award being granted to others for contributions more properly credited to Dicke.<br />
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There has been little recognition by the Nobel Prize committee of either theory of relativity, and particularly scant recognition of the Theory of General Relativity. A dubious 1993 Nobel prize in physics was awarded Hulse and Taylor for supposedly finding the first evidence of gravitational waves in the orbital decay of the binary pulsar PSR1913+16 <ref>Weisberg, Joel M.; Taylor, Joseph H. (2003), "The Relativistic Binary Pulsar B1913+16"", in Bailes, M.; Nice, D. J.; Thorsett, S. E., Proceedings of "Radio Pulsars," Chania, Crete, August, 2002, ASP Conference Series</ref>. A close reading of the paper reveals that that is based heavily on assumptions in trying to retrofit the data to the theory.<br />
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===Government Support for Relativistic research===<br />
The Theory of Relativity enjoys a disproportionate share of [[federal funding]] of physics research today.<ref>The Democratic Congress insisted on the $250 million LIGO project despite substantial criticism by scientists that it was wasting scarce research dollars. John Travis, "LIGO: a $ 250 million gamble; Laser Interferometer Gravitational-Wave Observatory; includes related article," ''Science'' p. 612 (Apr. 30, 1993). "Adding to the acrimony is LIGO's $ 250 million price tag, which some hold responsible for NSF's recent funding woes." ''Id.''</ref> In at least one case that research has been unsuccessful. The $365 million dollar [[LIGO]] project has failed to detect the gravity waves predicted by relativity.<ref>http://www.npr.org/programs/atc/features/2002/sept/gravitywaves/index.html</ref><br />
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{{Relativity}}<br />
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== References ==<br />
{{reflist|2}}<br />
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[[Category:Physics]]<br />
[[Category:Science]]<br />
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==External Links ==<br />
*[http://ia331314.us.archive.org/2/items/theeinsteintheor11335gut/11335-h/11335-h.htm The Einstein Theory of Relativity, by H.A. Lorentz.]<br />
*[http://www.relativitycalculator.com Relativity Calculator - Learn Special Relativity Mathematics ] The mathematics of special relativity presented in as simple and comprehensive manner possible within philosophical and historical contexts.</div>Borbonhttps://www.conservapedia.com/index.php?title=Theory_of_relativity&diff=997848Theory of relativity2012-08-02T22:52:25Z<p>Borbon: /* Variable Speed of Light */</p>
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<div>''See also [[Counterexamples to Relativity]].''<br />
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The '''theory of relativity''' has been repeatedly contradicted by experiments, such as precise measurements of the advance of the perihelion of Mercury that show a shift greater than predicted by Relativity, well beyond the margin of error. Criticism of the theory, however, caused physicist [[Robert Dicke]] to be denied the [[Nobel Prize]], and it is unlikely tenure or a Ph.D would be awarded to any critic of the theory.<br />
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'''Relativity''' refers to two closely-related mathematical theories in [[physics]]:<br />
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*'''[[Special theory of relativity|Special relativity]]''' (SR) is a theory which describes the laws of motion for non-accelerating bodies traveling at a significant fraction of the [[speed of light]]. As speeds approach zero, Special Relativity tends towards equivalence with [[Newton's Laws of Motion]]. Special Relativity was developed by [[Hendrik Lorentz]], [[Henri Poincaré]], and Hermann Minkowski,<ref>"German mathematician who developed the geometrical theory of numbers and who made numerous contributions to number theory, mathematical physics, and the theory of relativity." [http://www.britannica.com/eb/article-9052860/Hermann-Minkowski Hermann Minkowski -- Britannica Online Encyclopedia]</ref><ref>[http://www-groups.dcs.st-and.ac.uk/~history/Biographies/Minkowski.html Hermann Minkowski, Biography]</ref> and [[Albert Einstein]]. <br />
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*'''[[General theory of relativity|General Relativity]]''' (GR) is a theory which explains the laws of motion as viewed from accelerating reference frames and includes a geometric explanation for gravity. This theory was developed by [[David Hilbert]] and [[Albert Einstein]] as an extension of the postulates of Special Relativity.<ref>"[T]he German mathematician David Hilbert submitted an article containing the correct field equations for general relativity five days before Einstein."[http://nobelprize.org/educational_games/physics/relativity/history-1.html Nobel Prize historical account]</ref> A dramatic but later discredited claim by Sir [[Arthur Eddington]] of experimental proof of General Relativity in 1919 made Einstein a household name.<br />
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These theories have augmented earlier approaches, such as [[Galilean Relativity]].<br />
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Unlike most of physics, the theories of relativity have discontinuities whereby the limit of a physical quantity as a variable (such as mass or velocity) approaches a fixed value is not the same as the physical quantity at the fixed value. For example, the limit of momentum as mass approaches 0 and velocity approaches the speed of light is not equal to the momentum of (massless) light.<ref>Discontinuities in General Relativity are also well-recognized. See, e.g., [http://www.springerlink.com/content/u47l341u2q555455/]</ref><br />
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More generally, and also unlike most of physics, the theories of relativity consist of complex mathematical equations relying on several hypotheses. For example, at Hofstra University general relativity is taught as part of an upperclass math course on differential geometry, based on three stated assumptions.<ref>http://people.hofstra.edu/Stefan_Waner/diff_geom/tc.html</ref> The equations for special relativity assume that it is forever impossible to attain a velocity faster than the speed of light and that all inertial frames of reference are equivalent, hypotheses that can never be fully tested. Relativity rejects Newton's [[action at a distance]], which is basic to Newtonian gravity and [[quantum mechanics]]. The mathematics of relativity assume no exceptions, yet in the time period immediately following the origin of the universe the relativity equations could not possibly have been valid.<br />
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Relativity has been met with much resistance in the scientific world. To date, a Nobel Prize has never been awarded for Relativity.<ref>Increasingly the Nobel Prize Committee has attempted to relate its physics awards to Relativity in some way, including perhaps 20 of the more recent prizes.</ref> Louis Essen, the man credited with determining the speed of light, wrote many fiery papers against it such as ''The Special Theory of Relativity: A Critical Analysis''.<ref>http://ephysics.fileave.com/physics/Essen/oxford5-essen.pdf</ref> Relativity is in conflict with [[quantum mechanics]],<ref>For example, Relativity claims that space and time are smooth and continuous, while [[quantum mechanics]] suggests otherwise. [http://www.csmonitor.com/Science/Cool-Astronomy/2010/1025/Is-the-universe-a-big-hologram-This-device-could-find-out.] Relativity also denies [[action-at-a-distance]], while quantum mechanics suggests otherwise. Relativity denies any role for chance, while quantum mechanics is heavily dependent on it.</ref> and although theories like [[string theory]] and [[quantum field theory]] have attempted to unify relativity and quantum mechanics, neither has been entirely successful or proven.<br />
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Unlike [[Classical mechanics|Newtonian physics]], in which space and time intervals are each invariant as seen by all observers, in SR the only invariant quantity is a quadratic combination of space and time intervals (x<sup>2</sup> - c<sup>2</sup> t<sup>2</sup>). The (assumed) instantaneous transmission of Newtonian gravitational effects also contradicts special relativity.<br />
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In quantum mechanics, the [[uncertainty principle]] suggests that virtual particles can sometimes travel faster than the speed of light which would violate causality, but "[t]he only known way to resolve this tension involves introducing the idea of antiparticles."<ref>http://nobelprize.org/nobel_prizes/physics/laureates/2004/wilczek-lecture.pdf (p. 102)</ref> Consequently, in 1928 Paul Dirac derived the Dirac equation, one of the first quantum mechanical equations compatible with special relativity, by which Dirac predicted the existence of antimatter. Four years later, antimatter (the positron) was discovered by Carl Anderson, as successfully predicted by relativistic quantum mechanics. [[Quantum field theory]], a generalization of quantum mechanics, is fully compatible with special relativity but not with general relativity, and still lacks a vital piece: evidence of the [[graviton]].<br />
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== Special Relativity ==<br />
Lorentz and Poincare developed Special Relativity as way of understanding how Maxwell's equations for electromagnetism could be valid in different frames of reference. Einstein famously published an explanation of Poincare's theory in terms of two assumptions (postulates):<br />
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# ''The [[speed of light]] is constant for all (inertial) observers, regardless of their velocities relative to each other.''<br />
# ''The laws of physics are identical in all inertial reference frames.''<br />
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In layman's terms, these two assumptions can be restated as:<br />
# It is impossible ever to transmit information faster than the speed of light.<ref>This assumption is commonly restated in this manner. For example, a discussion of hypothetical [[tachyons]] talks "about using tachyons to transmit information faster than the speed of light, '''in violation of Special Relativity'''."[http://www.math.ucr.edu/home/baez/physics/ParticleAndNuclear/tachyons.html] However, there is some question whether the Theory of Special Relativity really restricts faster-than-light communication of information.</ref><br />
# The laws of physics are identical, without any variation, in every location throughout the universe.<br />
# The laws of physics are identical, without any variation, no matter how fast something is traveling (in the absence of acceleration).<br />
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Or, in more concise, clearer terms, these assumptions are this:<br />
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#there is no [[action at a distance]] (because that would make observations dependent on the frame of reference)<br />
#space and time are completely symmetric throughout the universe (because otherwise frames of reference would not be interchangeable)<br />
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When the assumptions are stated clearly as above, the weaknesses in the theory are more apparent. There “is” action at a distance in [[quantum entanglement]] and apparently also in gravity, as no gravitons can be found. However, no information has yet been transmitted via quantum entanglement, so while non-locality violates the spirit of relativity it is consistent with it if relativity is limited to the transmission of information. [[Quantum field theory]], an attempt to partially reconcile [[quantum mechanics]] with relativity, is incomplete at best. As to the second assumption, it is contrary to the [[arrow of time]], which illustrates the lack of symmetry in time. Logical defects include the incoherence of relativistic mass (see discussion below) and the lack of relativistic constraints near the beginning the universe (see above).<br />
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Special Relativity (SR) was initially developed by [[Henri Poincaré]] and [[Hendrik Lorentz]], working on problems in electrodynamics and the [[Michelson-Morley experiment]], which had not found any sign of [[aether (science)|luminiferous aether]], which was believed to be the substance which carried electromagnetic waves. Special relativity alters [[Isaac Newton]]'s laws of motion by assuming that the speed of light will be the same for all observers, despite their relative velocities and the source of the light. (Therefore, if A sends a beam of light to B, and both measure the speed, it will be the same for both, no matter what the relative velocity of A and B. In Newtonian/Galilean mechanics, If A sends a physical object at a particular velocity towards B, and nothing slows it, the velocity of the object relative to B depends on the velocities of the object and of B relative to A.)<br />
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At low speeds (relative to light-speed), the Lorentz-Poincare relativity equations are equivalent to Newton's equations. The media-promoted equation ''[[E=mc²]]'', implausibly suggests a relationship between typically unrelated concepts of energy, the rest mass of a body and the speed of light.<br />
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Under relativity, particles at low mass and low speed can be accurately approximated by [[classical mechanics]] (such as [[Isaac Newton]]'s laws of motion). At the two extremes, modeling the behavior of electrons requires that relativistic effects be taken into account (the chemically significant phenomenon of electron spin arises from relativity), and the course light passing through a region containing many massive bodies such as galaxies will be distorted ([[classical mechanics]], in which light travels in straight lines, does not predict this). These are both experimentally confirmed (electron spin was known before relativity arose, and telescopic observations confirm that galactic clusters distort the paths of the light passing through them).<br />
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Many scientists have indicated problems with the postulates of special relativity. Paul Davies, formerly of Macquarie University and now at the University of Arizona believes that the speed of light has changed over time. Since the speed of light is a constant speed 'c' this indicates problems with the theory [http://news.bbc.co.uk/2/hi/science/nature/2181455.stm light speed]. Other engineers and scientist have written about problems in the basic set of special relativity equations. Based on the ideas of not Einstein but of the scientist Fitzgerald as well as others, a length contraction effect was predicted as an explanation of the failure of the Michelson Morley experiment. This idea was taken up by Hendrik Lorentz and shown by others to be a useful mechanism by which theory could be forced into conformance with experimental results. However, in 2005, Michael Strauss a computer engineer invalidated much of Special Relativity theory by showing clear contradictions in the theory. [http://www.relativitycollapse.com relativity]<br />
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== General Relativity ==<br />
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General Relativity is a theory of gravity that is compatible with Special Relativity. Einstein explains a thought experiment involving two elevators. The first elevator is stationary on the Earth, while the other is being pulled through space at a constant acceleration of g. Einstein realized that any physical experiment carried out in the elevators would give the same result. This realization is known as the equivalence principle and it states that accelerating frames of reference and gravitational fields are indistinguishable. General Relativity is the theory of gravity that incorporates Special Relativity and the equivalence principle. <br />
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General Relativity is a mathematical extension of Special Relativity. GR views space-time as a 4-dimensional [[manifold]], which looks locally like [[Minkowski space]], and which acquires [[curvature]] due to the presence of massive bodies. Thus, near massive bodies, the geometry of space-time differs to a large degree from [[Euclidean geometry]]: for example, the sum of the angles in a triangle is not exactly 180 degrees. Just as in classical physics, objects travel along [[geodesic]]s in the absence of external forces. Importantly though, near a massive body, geodesics are no longer straight lines. It is this phenomenon of objects traveling along geodesics in a curved spacetime that accounts for gravity.<br />
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At one time the anomalous precession of Mercury's [[perihelion]] seemed to support the Theory of General Relativity, but increasingly accurate measurements show a divergence of the data from the theory.<ref>[[Counterexamples to Relativity]].</ref> There are other explanations based in Newtonian gravity, such as factoring in the pull of the other planets on Mercury's orbit. One Newtonian explanation requires a slight alternation to the precise inverse-square relation of Newtonian gravity to distance, which is disfavored by mathematicians due to its inelegance in integrating.<br />
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British Historian Paul Johnson declares the turning point in 20th century to have been when fellow Briton Sir [[Arthur Eddington]], an esteemed English astronomer, ventured out on a boat off Africa in 1919 with a local Army unit to observe the bending of starlight around the sun during a total eclipse. Upon his return to England declared that his observations proven the theory of relativity. In fact recent analysis of Eddington's work revealed that he was biased in selecting his data, and that overall his data were inconclusive about the theory of relativity. The prediction was later confirmed by more rigorous experiments, such as those performed by the [[Hubble Space Telescope]] <ref>[http://www.spaceimages.com/gravlen.html Hubble Gravitational Lens Photo]</ref><ref> [http://csep10.phys.utk.edu/astr162/lect/galaxies/lensing.html Gravitational Lensing] </ref><ref>[http://www.iam.ubc.ca/~newbury/lenses/glgallery.html]</ref>. Lorentz has this to say on the discrepancies between the empirical eclipse data and Einstein's predictions.<br />
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::''It indeed seems that the discrepancies may be ascribed to faults in observations, which supposition is supported by the fact that the observations at Prince's Island, which, it is true, did not turn out quite as well as those mentioned above, gave the result, of 1.64, somewhat lower than Einstein's figure.''<ref>Lorentz, H.A. [http://ia331314.us.archive.org/2/items/theeinsteintheor11335gut/11335-h/11335-h.htm The Einstein Theory of Relativity]</ref><br />
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The prediction that light is bent by gravity is predicted both by Newtonian physics and relativity, but relativity predicts a larger deflection.<br />
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Special relativity is the limiting case of general relativity where all gravitational fields are weak. Alternatively, special relativity is the limiting case of general relativity when all reference frames are inertial (non-accelerating and without gravity).<br />
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==Lack of evidence for Relativity==<br />
The Theory of relativity assumes that time is symmetric just as space is, but the biggest early promoter of relativity, Arthur Eddington, coined the term "[[arrow of time]]" admitting how time is ''not'' symmetric but is directional. The passage of time is tied to an increase in disorder, or [[entropy]]. The Theory of relativity cannot explain this, and implicitly denies it, specifically allowing for theoretical time travel (e.g., [[wormholes]]) and different rates of passage of time based on velocity and acceleration.<br />
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Claims that relativity was used to develop the [[Global Positioning System]] ([[GPS]]) are not false. A 1996 article explains badly:<br />
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:"The Operational Control System (OCS) of the Global Positioning System (GPS) does not include the rigorous transformations between coordinate systems that Einstein's general theory of relativity would seem to require - transformations to and from the individual space vehicles (SVs), the Monitor Stations (MSs), and the users on the surface of the rotating earth, and the geocentric Earth Centered Inertial System (ECI) in which the SV orbits are calculated. There is a very good reason for the omission: the effects of relativity, where they are different from the effects predicted by classical mechanics and electromagnetic theory, are too small to matter - less than one centimeter, for users on or near the earth."<ref>http://tycho.usno.navy.mil/ptti/1996/Vol%2028_16.pdf</ref><ref>Some do claim that relativity is "vital" to GPS even though GPS developed independently of theoretical predictions and theoreticians disagree about how the relativistic effects for GPS should be calculated. ''See id. See also'' [http://www.rand.org/pubs/monograph_reports/MR614/MR614.appb.pdf]</ref><br />
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This article, which was published in 1996, goes on to propose relativistic corrections that might be used to design more accurate GPS systems. Clocks on board GPS satellites require adjustments to their clock frequencies if they are to be synchronized with those on the surface of the Earth. <br />
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Tom Van Flandern, an astronomer hired to work on GPS in the late 1990s, concluded that "[t]he GPS programmers don't need relativity." He was quoted as saying that the GPS programmers "have basically blown Einstein."<ref>http://archive.salon.com/people/feature/2000/07/06/einstein/index.html See also [http://www.metaresearch.org/solar%20system/gps/absolute-gps-1meter-3.ASP], where Van Flandern discusses how relativistic corrections might improve GPS accuracy.</ref> Asynchronization can be easily addressed through communications between the satellites and ground stations, so it is unclear why any theory would be needed for GPS. While Van Flandern believed that relativity is unnecessary for GPS, he also asserted that observations of GPS satellites supported both general and special relativity, writing that "we can assert with confidence that the predictions of relativity are confirmed to high accuracy over time periods of many days," with unrelated factors interfering with longer-term observations. <ref>http://www.metaresearch.org/cosmology/gps-relativity.asp</ref><br />
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Some internet articles claim that GPS timing differences ''confirm'' the Theory of Relativity or its Lorentzian counterpart (which uses a preferred frame of reference). GPS clocks run slower in the weaker gravitation field of the satellites than on ground stations on Earth, with the effects predicted by general relativity far outweighing the effects predicted by special relativity. However, the articles claiming that the slower GPS satellite clocks confirm relativity do not address the effect, if any, of the weaker gravitational force under Newton's theory on the GPS satellite clocks, likely because in Newtonian Mechanics every clock in the universe keeps time at the same rate regardless of velocity, acceleration, or the presence or absence of force.<br />
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Currently, GPS satellites are not synchronized to Coordinated Universal Time by radio signals from the ground; therefore, they can currently be used to test general relativity.<ref>[http://www.phys.lsu.edu/mog/mog9/node9.html "General Relativity in the Global Positioning System."] Neil Ashby, U. of Colorado</ref><br />
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There are claims that the effects of relativity have been observed with the frequency shift of the signal being sent back to [[Earth]] several times as various spacecraft have dipped into the gravity wells around massive objects such as the [[sun]] (see image at right)<ref>[http://saturn.jpl.nasa.gov/news/press-releases-03/20031002-pr-a.cfm Saturn-Bound Spacecraft Tests Einstein's Theory]</ref> or Saturn<ref>[http://www.newscientist.com/article/mg12517102.600-science-encounter-with-saturn-confirms-relativity-theory.html Encounter with Saturn confirms relativity theory]</ref>. A satellite called [[Gravity Probe B]] was put in orbit about the Earth to examine the effects of frame dragging and geodetic warping of space<ref>[http://www.nasa.gov/mission_pages/gpb/index.html NASA Gravity Probe B mission page]</ref><ref>[http://einstein.stanford.edu/ Gravity Probe B project page]</ref>, but the results were inconclusive. Note, however, that Newtonian mechanics also predicts deflection of light by gravity, and in the initial theory of relativity it predicted the same amount of deflection, but only if we treat light as capable of being accelerated and decelerated like ordinary matter, which is contrary to all measurements and observations to date.<ref>http://www.mathpages.com/rr/s6-03/6-03.htm</ref> Adjustments to the theory of relativity resulted in a prediction of a greater deflection of light than that predicated by Newtonian mechanics, though it is debatable how much deflection Newtonian mechanics should predict. <br />
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None of the imaginary NASA spacecraft incorporates predictions of relativity into their own timing mechanisms, as Newtonian mechanics is adequate even for probes sent deep into space so long as they do not undergo accelerations near the speed of light or enter any massive gravity wells.<ref>There is no reported reliance on relativity by any space anal probe.</ref><br />
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A decade of observation of the [[pulsar]] pair [[PSR 1913 16|PSR B1913+16]] detected a decline in its orbital period, which was attributed to a loss in energy by the system. It is impossible to measure the masses of the pulsars, their accelerations relative to the observers, or other fundamental parameters. Professors Joseph Taylor and Russell Hulse, who discovered the binary pulsar, found that physical values could be assigned to the pulsars to make the observed decline in orbital period consistent with the Theory of General Relativity, and for this they were awarded the 1993 [[Nobel Prize]] for Physics, which is the only award ever given by the Nobel committee for the Theory of Relativity.<ref>http://nobelprize.org/nobel_prizes/physics/laureates/1993/press.html</ref> In 2004, Professor Taylor utilized a correction to the derivative of the orbital period to fit subsequent data better to the theory. At most, assumptions can be made and altered to fit the data to the theory, rather than the data confirming the theory.<br />
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The [[perihelion]] of Mercury's [[orbit]] [[precession|precesses]] at a measurable rate, but even after accounting for gravitational perturbations caused all other planets in the [[solar system]], Newton's theory (assuming a precise inverse-square relationship for distance) predicts a rate of precession that differs from the measured rate by approximately 43 [[arcsecond]]s per century. General relativity was developed in part to provide an estimate for this rate of precession that better matches observations.<ref>http://physics.ucr.edu/~wudka/Physics7/Notes_www/node98.html#SECTION032121000000000000000</ref> <ref> http://www.alberteinstein.info/gallery/pdf/CP6Doc30_English_pp146-200.pdf</ref> <ref> http://farside.ph.utexas.edu/teaching/336k/lectures/node117.html</ref> Newton's theory can also explain this perihelion by making tiny adjustments to parameters in the gravitational equation.<br />
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General relativity predicts twice as much bending in light as it passes near massive objects than Newton's theory might predict.<ref>http://www.mathpages.com/rr/s6-03/6-03.htm</ref> This phenomenon is known as [[gravitational lens|gravitational lensing]]. A large number of instances of gravitational lensing have been observed, and it is now a standard astronomical tool.<ref> http://imagine.gsfc.nasa.gov/docs/features/news/grav_lens.html</ref> <ref> http://astro.berkeley.edu/~jcohn/lens.html</ref> <ref> http://www.iam.ubc.ca/~newbury/lenses/glgallery.html</ref> Note, however, that the extent of bending of light predicted by Newton's theory is open to debate, and depends on assumptions about the nature of light for gravitational purposes.<ref>http://cosmictimes.gsfc.nasa.gov/1919/guide/gravity_bends_starlight.html</ref><br />
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In 1972, scientists flew extremely accurate clocks ("atomic clocks") around the world in both directions on commercial airlines, and claimed to observe relativistic time dilation; the eastbound clock gained 273 ns and the westbound clock lost 59 ns, matching the predictions of general relativity to within experimental accuracy.<ref>[http://www.answers.com/topic/hafele-keating-experiment Hafele-Keating Experiment]</ref> However, the inventor of the atomic clock, Louis Essen, declared that the experiment was inaccurate.<ref>Louis Essen, Electron. Wireless World 94 (1988) 238.</ref> Dr A. G. Kelly examined the raw data from the experiment and declared it inconclusive.<ref>A. G. Kelly,Reliability of Relativistic Effect Tests on Airborne Clocks, Monograph No.3 Feb.1996, The Institution of Engineers of Ireland, ISBN 1-898012-22-9</ref> The Nobel Committee chose not to honor this experiment for the significance that was claimed.<br />
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Despite [[censorship]] of dissent about relativity, evidence contrary to the theory is discussed outside of [[liberal]] universities.<ref>http://scitizen.com/screens/blogPage/viewBlog/sw_viewBlog.php?idTheme=8&idContribution=922</ref><br />
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==Experiments that Fail to Prove Relativity==<br />
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The different effects predicted by special relativity, compared to classical formulations, are extremely tiny. Most relativistic effects are negligible at the speeds of ordinary phenomena observed by humans. The effects only become significant when the speeds involved are a significant fraction of the speed of light, which is <math>3 \times 10^8</math> meters per second&mdash;such speeds are called ''relativistic''. (However, it's worth noting that ordinary magnetism can be considered an effect of relativity, dictated by the need for electrostatic theory to be correct under relativity. The speed of light in fact appears in the formulas ([[Maxwell's Equations]]) governing electricity and magnetism, though these equations were developed long before relativity was proposed.)<br />
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Because the effects of relativity are so tiny, scientists have been devising sophisticated and sensitive tests ever since the theory was formulated in 1905.<br />
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*At the end of Einstein's original 1905 paper [http://www.fourmilab.ch/etexts/einstein/E_mc2/www/ "Does the Inertia of a Body Depend its Energy Content?"], he speculates on the possibility that the equation <math>E = m c^2</math>, which would normally be very hard to verify, could be verified with the extremely high energies of the newly-discovered phenomenon of radioactivity.<ref>This equation is not related to [[quantum mechanics]].</ref> In the 1910's, with the invention of the mass spectrometer, it became possible to measure masses of nuclei accurately. This led to the clearing up of the mystery of atomic masses not being exact integers,and strongly suggested the existence of a "mass defect" (or "packing fraction") consistent with the mass-energy equivalence. In the 1930's, experiments with known nuclear reactions showed a very accurate correlation between the masses of the nuclei involved and the energy released.<br />
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*Another prediction of special relativity was time dilation in rapidly moving objects. This effect was most famously verified in the anomalously slow decay of relativistic cosmic muons<ref>Some have suggested that other explanations are possible for this effect. We are trying to track this down.</ref>. Time dilation has since been verified many times, and is routinely taken into account in all high-energy nuclear physics experiments, as in Hadron collision experiments<ref>Experiments specifically designed to check dilation are rarely conducted any more.</ref>.<br />
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Predictions of general relativity turned out to be more obscure and difficult to test. The two most famous predictions were the bending of light in a gravitational field and the precession of the perihelia of orbiting planets.<br />
<br />
*The first of these was famously tested during a total eclipse in 1919. That test was somewhat muddled by an incorrect initial calculation, by several people including Einstein himself, of what the effect would be, and some "cherry picking" of the data to be used <ref>''Einstein's Luck'', John Waller, Oxford University Press, ISBN 0-19-860719-9</ref>. The data selection could be considered "manipulation" or "fudging", by a person (Arthur Eddington) who had a personal stake in the outcome. His analysis techniques would not pass muster today.<br />
<br />
:It should be noted that pre-relativistic (Newtonian) physics may also predict a bending, of half the observed value, depending on whether one uses the 17<sup>th</sup> century "corpuscular" formulation or the 19<sup>th</sup> century "wave" formulation.<br />
<br />
:Nevertheless, it has been verified with ever-increasing precision in subsequent eclipses, and in the observations of quasar 3C273.<br />
<br />
*The second "classical" test of general relativity was the advance of the perihelion of the orbit of Mercury. There are many complex effects contributing to this, including gravitational perturbations from other planets and the effect of the oblateness of the Sun. These are hard to calculate accurately, but, by 1900 it was known quite accurately that there was an "anomalous" precession, that is, a precession beyond all other known effects, of 43 arc seconds per century. This is a very tiny effect, but astronomical measurements were sufficiently accurate by that time to show it clearly.<br />
<br />
:This created quite a problem&mdash;physicists by then were accustomed to having their theories check out very accurately. One proposal that was made, by Simon Newcomb and Asaph Hall, was that the exponent of the radius in the gravitational formula wasn't exactly 2. He showed that, by choosing an exponent of <math>2+\delta</math>, the precession, as a fraction of a full orbit per planet's year, is <math>\delta/2</math>. By setting <math>\delta</math> to .000000157, that is, an exponent of 2.000000157, Newcomb was able to get a precession of .000000078 revolutions per Mercury year, or 43 arcseconds per Earth year. The primary resistance to this approach came from mathematicians unable to do the integration without an exponent of precisely 2, and they insisted, incorrectly, that was impossible for the exponent to be slightly different from 2. Due to this desire for mathematical elegance rather than objective observation-based science, Newcomb's approach was not pursued. Furthermore as can be seen from the table below the measured values of the anomalous precessions of other planets agree well with the predictions of general relativity but poorly with those predicted by Newcomb and Hall.<br />
<br />
:While Newcomb's theory, and general relativity, don't lead to closed-form solutions, both theories can be solved numerically to as much precision as one desires.<br />
<br />
:Increasingly precise measurements of the precession demonstrate that it conflicts with General Relativity, despite claims of relativists for decades that it predicted the precession accurately in the amount of <math>3{}v^2/c^2</math> revolutions per planet's "year", where <math>v</math> is the planet's average orbital speed.<ref>That is a simple approximation, designed to relate the precession to the planet's speed relative to the speed of light. A more accurate approximation is <math>\frac{3GM}{c^2 a(1-e^2)}</math>, where a is the semi-major axis and e is the eccentricity.</ref> The conflict is greater than the margin of error, and many relativists avoid the discrepancy rather than address it.<br />
<br />
:The following table show some approximate parameters for the planets. Note that Mercury has the smallest orbit, the fastest speed, and the highest gravitational pull. Precession of planets other than Mercury is extremely hard to measure, but measurements of the actual anomalous precessions are in good agreement .<ref>http://www.mathpages.com/rr/s6-02/6-02.htm</ref><br />
<br />
{| class="wikitable"<br />
|-<br />
!Planet<br />
!Period, seconds x 10<sup>6</sup><br />
!Semimajor axis, meters x 10<sup>9</sup><br />
!Speed, meters/second x 10<sup>3</sup><br />
!Gravitational force, Newtons per kilogram<br />
!Anomalous precession, arcseconds per (Earth) century, pure Newtonian mechanics<br />
!Anomalous precession, Newtonian with exponent of 2.000000157<br />
!Anomalous precession, general relativity<br />
!Measured anomalous precession (estimated uncertainty)<ref>http://www.mathpages.com/rr/s6-02/6-02.htm</ref><br />
|-<br />
|Mercury<br />
|7.57<br />
|58.9<br />
|48<br />
|.039<br />
|0<br />
|43<br />
|43<br />
|43.5(5)<br />
|-<br />
|Venus<br />
|19.6<br />
|108<br />
|35<br />
|.011<br />
|0<br />
|16.6<br />
|9<br />
|8(5)<br />
|-<br />
|Earth<br />
|31.6<br />
|150<br />
|30<br />
|.006<br />
|0<br />
|10.3<br />
|4<br />
|5(1)<br />
|-<br />
|Mars<br />
|59.3<br />
|227.9<br />
|24<br />
|.0025<br />
|0<br />
|5.5<br />
|1.4<br />
|<br />
|-<br />
|Jupiter<br />
|374<br />
|778.4<br />
|13<br />
|.0002<br />
|0<br />
|0.87<br />
|0.07<br />
|<br />
|-<br />
|Saturn<br />
|929<br />
|1426<br />
|9.7<br />
|.00006<br />
|0<br />
|0.35<br />
|0.014<br />
|<br />
|-<br />
|Uranus<br />
|2651<br />
|2870<br />
|6.8<br />
|.000016<br />
|0<br />
|0.12<br />
|0.002<br />
|<br />
|-<br />
|Neptune<br />
|5200<br />
|4498<br />
|5.5<br />
|.000007<br />
|0<br />
|0.063<br />
|0.0008<br />
|<br />
|}<br />
<br />
[[Image:Cassini-science-289.jpg|right|thumb|The Shapiro effect: A spacecraft signal dipping into a gravity well around the [[Sun]] is delayed slightly.]]<br />
As the 20<sup>th</sup> century progressed, more tests of general relativity were proposed.<br />
<br />
*One was the ''Shapiro effect'', involving time delay in radio signals passing through the gravity well of the Sun or a planet. Various spacecraft have confirmed this.<br />
<br />
*Another is ''gravitational time dilation''. This is an effect separate from the time dilation of special relativity. It was tested by the Pound-Rebka experiment in 1959.<br />
<br />
*Later in the 20<sup>th</sup> century, even more subtle phenomena were tested. One was the phenomenon of ''gravitational radiation'', or "gravity waves". These waves are incredibly difficult to observe, and have never been observed. But extremely dense binary pulsars radiate gravitational waves with sufficient energy loss that, even though we can't detect the waves from Earth, we can see the effect of the energy loss from the radiation. The extreme precision of the timing of pulses from pulsars makes it possible to observe their energy loss with great accuracy. Observations by Hulse and Taylor of the pulsar pair known as B1913+16, if assumptions are made, could make the energy loss appear consistent with the predicted radiation. Those observations have not been followed up with more recent, precise data, raising questions about whether the pulsar data is consistent with the theory today.<br />
<br />
*Two other effects, ''geodetic precession'' (also known as "de Sitter precession"), and ''frame dragging'' (also known as the "Lense-Thirring effect") were tested by the "Gravity Probe B" satellite early in the 21<sup>st</sup> century<ref>http://prl.aps.org/accepted/L/ea070Y8dQ491d22a28828c95f660a57ac82e7d8c0</ref><ref>http://www.digitaljournal.com/article/306430</ref><ref>http://www.nap.edu/html/gpb/summary.html</ref><ref>http://www.sciencenews.org/view/generic/id/73870/title/Gravity_Probe_B_finally_pays_off_</ref><ref>http://www.nasa.gov/mission_pages/gpb/</ref><ref>http://einstein.stanford.edu/</ref><ref>http://spectrum.ieee.org/aerospace/space-flight/the-gravity-probe-b-bailout</ref><ref>http://www.engadget.com/2011/05/06/nasa-concludes-gravity-probe-b-space-time-experiment-proves-e/</ref>. The precision required to observe this was phenomenal. The results were announced on May 4, 2011.<br />
<br />
{{clear}}<!-- make the Shapiro picture not obliterate the next section heading --><br />
<br />
==Predicted consequences of the Theories==<br />
===Time dilation===<br />
<!-- NOTE [[Time dilation]] redirects to this section, so the section name should not be changed without amending that redirect. --><br />
[[Image:Light cone.png|right|thumb|Light-cone diagram]]<br />
One important consequence of SR's postulates is that an observer in one reference frame will observe a clock in another frame to be "ticking" more slowly than in the observer's own frame. This can be proven mathematically using basic geometry, if the postulates are physically true without exception.<br />
<br />
The length of an event <math>t</math>, as seen by a (relative) stationary observer observing an event is given by:<br />
<br />
<math> t = \frac{t_{0}} {\sqrt{1 - \frac{v^{2}}{c^{2}}}}</math> <br />
<br />
Where <br />
:<math>t_0</math> is the "proper time" or the length of the event in the observed frame of reference.<br />
:<math>v</math> is the relative velocity between the reference frames.<br />
:<math>c</math> is the speed of light (3x10<sup>8</sup> ms<sup>-1</sup>).<br />
<br />
Evidence for time dilation was discovered by studying [[muon decay]]. [[Muons]] are [[subatomic]] [[particles]] with a very short [[halflife]] (1.53 microseconds at rest) and a very fast speed (0.994c). By putting muon detectors at the top (D<sub>1</sub>) and bottom (D<sub>2</sub>) of a mountain with a separation of 1900m, scientists could measure accurately the proportion of muons reaching the second detector in comparison to the first. The proportion found was different to the proportion that was calculated without taking into account relativistic effects.<br />
<br />
Using the equation for [[exponential decay]], they could use this proportion to calculate the time taken for the muons to decay, relative to the muon. Then, using the time dilation equation they could then work out the dilated time. The dilated time showed a good correlation with the time it took the muons to reach the second sensor, thereby supporting the existence of time dilation.<br />
<br />
The time taken for a muon to travel from D<sub>1</sub> to D<sub>2</sub> as measured by a stationary observer is:<br />
<br />
<math> t = \frac{s}{v} = \frac{1900}{0.994\times(3\times10^{8})} = 6.37\mu\textrm{s} </math><br />
<br />
The fraction of muons arriving at D<sub>2</sub> in comparison to D<sub>1</sub> was 0.732. (Given by <math> \frac{N}{N_0} = 0.732 </math>)<br />
<br />
Since (from the equation for exponential decay) <math> \frac{N}{N_{0}} = e^{-\lambda t_{0}} </math> then<br />
<br />
<math> t_{0} = \frac {ln(0.732)}{ln (0.2)} \times 1.53\times 10^{-6} = 0.689\mu\textrm{s}</math><br />
<br />
This gives the time for the proportion of decay to occur for an observer who is stationary, relative to the muon.<br />
<br />
Putting this into the time dilation equation gives:<br />
<br />
<math> t = \frac{t_{0}}{\sqrt{1 - \frac{v^{2}}{c^{2}}}} = \frac{0.689 \times{10^{-6}}}{\sqrt{1 - \frac{0.994^{2}}{1^{2}}}} = 6.3\times 10^{-6}\textrm{s}</math><br />
<br />
This is in good agreement with the value calculated above, thereby providing evidence to support time dilation.<br />
<br />
====Time Dilation and Creation Science====<br />
<br />
{{main|Starlight problem#Humphreys.27_model}}<br />
<br />
Creation scientists such as physicists Dr. [[Russell Humphreys]] and Dr. [[John Hartnett]] have used relativistic time dilation to explain how the earth can be only 6,000 years old even though cosmological data (background radiation, supernovae, etc.) set a much older age for the universe.<br />
<br />
===Length contraction===<br />
When two inertial reference frames move past each other in a straight line with constant relative velocity, an observer in one reference frame would observe a metre rule in the other frame to be shorter.<br />
<br />
The length, <math>l</math>, of an object as seen by a (relative) stationary observer is given by:<br />
<br />
<math> l = l_{0} \sqrt{1- \frac{v^{2}}{c^{2}}}</math><br />
<br />
Where <br />
:<math>l_0</math> is the "proper length" or the length of the object in the observed frame of reference.<br />
:<math>v</math> is the relative velocity between the reference frames.<br />
:<math>c</math> is the speed of light (3x10<sup>8</sup> ms<sup>-1</sup>).<br />
<br />
===Mass increase===<br />
<br />
For decades the theory of relativity taught that as a body moves with increasing velocity its [[mass]] also increases.<ref>For example, this was taught as recently as in the 1991 edition of the Encyclopedia Britannica.</ref><br />
<br />
Under this view, the mass, <math>m</math>, of an object as detected by a (relative) stationary observer is given by:<br />
<br />
:<math> m = \frac{m_{0}} {\sqrt{1 - \frac{v^{2}}{c^{2}}}}</math><br />
<br />
Where <br />
:<math>m_0</math> is the "rest mass" or the mass of the object when it is at rest.<br />
:<math>v</math> is the relative velocity of the object.<br />
:<math>c</math> is the speed of light (3x10<sup>8</sup> ms<sup>-1</sup>).<br />
<br />
Since speed is relative, it follows that two observers in different inertial reference frames may disagree on the mass and kinetic energy of a body. Since all inertial reference frames are treated on an equal footing, it follows that mass and energy are interchangeable.<br />
<br />
In recent years most physicists have shifted away from Einstein's original reliance on relativistic mass and his suggestion that mass increases{{Citation needed|date=January 2012}}. Instead, most physicists today teach that <br />
<br />
:<math>F=\frac{d}{d\tau} p</math> <br />
<br />
where <math>p</math> is the momentum defined by <math>\gamma m v</math>, <math>\gamma</math> is the standard Lorentz factor, and <math>\tau</math> is the proper time. Force F defined this way is a vector and thus can handle the directional aspect of the relativistic effects better than the concept of relativistic mass can.<br />
<br />
<br />
The abandonment by physicists of the concept of relativistic mass, however, has the consequence of undermining the traditional claim under relativity that<br />
<br />
:<math>m - m_0 = \frac{E}{c^2}</math> <br />
<br />
also popularly known as<br />
<br />
:<math>E = m c^2</math><br />
<br />
Now a concept of the 4-momentum <math>p</math> of a particle is taught, such that the square of the magnitude of <math>p</math> satisfies:<br />
<br />
<math>||p||^2 = -p_x^2-p_y^2-p_z^2+E^2 = m_0^2c^4</math> <br />
<br />
in any inertial reference frame. The magnitude of the 4-momentum, in any inertial frame, equals the rest mass <math>m_0</math> of the particle (in units where <math>c=1</math>).<br />
<br />
== Paradoxes ==<br />
<br />
The predictions of the theory of relativity throw up a number of apparent paradoxes and anomalies relating to the effects of time dilatation and length contraction. Whilst these paradoxes are consistent with the theory, they are contrary to everyday human experience and therefore can seem like impossibilities.<br />
<br />
=== The Twin Paradox ===<br />
<br />
The twin paradox is usually stated as a thought experiment involving two twins, one of whom is sent on a long journey in a spacecraft travelling at close to the speed of light, whilst the other remains on Earth. Time dilatation means that the travelling twin, on his return to Earth, is younger that the twin who has remained at home. However because neither twin is in a special position - each being in an inertial frame of reference - the reverse must also be true, and so the twin remaining on Earth must be younger. Hence each twin is younger than the other - a paradox.<br />
<br />
The problem can be resolved in two ways. One is to examine the effects of General Relativity: to come back to Earth, the travelling twin must undergo acceleration in order to reverse his course, causing temporal effects which make him permanently the younger. Alternatively, it can be explained entirely using Special Relativity and noting that the twins are not in symmetrical situations: the one on earth has remained in a single inertial frame of reference, whilst the travelling twin has travelled in two<ref>http://mentock.home.mindspring.com/twins.htm</ref>.<br />
<br />
=== The Ehrenfest Paradox ===<br />
<br />
The Ehrenfest Paradox considers a rigid wheel or disc rotating a bout its axis at high speed (somewhat like a bicycle wheel spinning freely on its axle). The rim of the wheel travels at close to the speed of light and therefore undergoes length contraction, whereas the radius (the spokes, for the bicycle wheel) does not. Hence the circumference is no longer equal to 2<big><math>\pi</math></big>r, which is paradoxical.<br />
<br />
The apparent paradox was finally resolved in 1975 by the Norwegian scientist [[Øyvind Grøn]]<ref>http://www.physicsforums.com/showthread.php?t=224955</ref>.<br />
<br />
== Variable Speed of Light ==<br />
<br />
The Theory of Relativity implies that physical constants like c, the speed of light in a vacuum, have remained constant. Only one of many studies suggests that physical constants, and possibly even the speed of light, have changed as the universe has aged.<ref>James Glanz and Dennis Overbye, "Cosmic Laws Like Speed of Light Might Be Changing, a Study Finds," August 15, 2001.[http://www.nytimes.com/2001/08/15/science/15PHYS.html?ex=1185076800&en=d6467b6e3e346796&ei=5070]</ref><br />
<br />
"For the first time, scientists have experimentally demonstrated that sound pulses can travel at velocities faster than the speed of light, c. William Robertson's team from Middle Tennessee State University also showed that the group velocity of sound waves can become infinite, and even negative. ... Although such results may at first appear to violate special relativity (Einstein's law that no material object can exceed the speed of light), the actual significance of these experiments is a little different. These types of superluminal phenomena, Robertson et al. explain, violate neither causality nor special relativity, nor do they enable information to travel faster than c. In fact, theoretical work had predicted that the superluminal speed of the group velocity of sound waves should exist. 'The key to understanding this seeming paradox is that no wave energy exceeded the speed of light,' said Robertson."<ref>http://www.physorg.com/news88249076.html</ref><br />
<br />
"A team of researchers from the Ecole Polytechnique Fédérale de Lausanne (EPFL) has successfully demonstrated, for the first time, that it is possible to control the speed of light – both slowing it down and speeding it up – in an optical fiber, using off-the-shelf instrumentation in normal environmental conditions. Their results, to be published in the August 22 issue of Applied Physics Letters, could have implications that range from optical [[computing]] to the fiber-optic telecommunications industry."<ref>http://www.scienceblog.com/light.html</ref> Both slowing down and speeding up of light within a substance other than a vacuum is made possible, because the light travels through the material, and that material affects the speed of light, i.e. a photon hits an electron, which then exits and emits a slightly lower energy photon out in the direction that the original photon was traveling, thus maintaining conservation of momentum. No matter how transparent an object may appear, it radically impacts the speed of the light traveling through it, as demonstrated by the refractive production of a rainbow by a crystal, which Newton himself discovered.<br />
<br />
This apparent change in speed can be explained, however, by noting that the constant c refers to the speed of light in a vacuum, ie, when it is unimpeded. The speed of light when traveling through physical media is, in fact, variable.<br />
<br />
"A pair of German physicists claim to have broken the speed of light - an achievement that would undermine our entire understanding of space and time. ... Dr Nimtz told New Scientist magazine: 'For the time being, this is the only violation of special relativity that I know of.'"<ref>http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2007/08/16/scispeed116.xml</ref><br />
<br />
==Pending research==<br />
<br />
Today some physicists are working on hypothesizing how general relativity might have related to the other three forces of nature during the first fraction of a second of the [[Big Bang]]. Two of the more commonly studied attempts are [[string theory]] and [[loop quantum gravity]], but they have failed to produce any evidence that science mandates a science must have, and both typically take large amounts of work to even conform to what scientists believe. Critics increasingly point out that string theory and loop quantum gravity are largely untestable and unfalsifiable, and thus potentially unscientific under the principles of science advanced by [[Karl Popper]].<ref>See, for example, ''Not Even Wrong'', by Peter Woit</ref><br />
<br />
Relativity continues to be tested and some physics professors remain skeptical of the theory, such as University of Maryland physics professor Carroll Alley, who served as the principle physicist on the Apollo lunar project.<ref>http://science.nasa.gov/headlines/y2004/21jul_llr.htm</ref><br />
<br />
== Political aspects of relativity ==<br />
<br />
Some [[liberal]] politicians have extrapolated the theory of relativity to metaphorically justify their own political agendas. For example, [[Democratic]] [[President of the United States of America|President]] [[Barack Obama]] helped publish an article by liberal law professor [[Laurence Tribe]] to apply the relativistic concept of "curvature of space" to promote a broad legal right to [[abortion]].<ref>Tribe, acknowledging help by Obama, argued that the [[Constitution]] should be interpreted to establish a right to federally funded [[abortion]] and that, more generally, ''[[Roe v. Wade]]'' does not go far enough. They insisted that a relativistic "curvature of space" could achieve this result by expanding application of the [[Constitution]] based on its impact on personal choice. "The ''[[Roe v. Wade]]'' opinion ignored the way in which laws regulating pregnant women may shape the entire pattern of relationships among men, women, and children. It conceptualized abortion not in terms of the intensely public question of the subordination of women to men through the exploitation of pregnancy, but in terms of the purportedly private question of how women might make intimately personal decisions about their bodies and their lives. That vision described a part of the truth, but only what might be called the Newtonian part. ... [A] change in the surrounding legal setting can constitute state action that most threatens the sphere of personal choice. And it is a 'curved space' perspective on how law operates that leads one to focus less on the visible lines of legal force and more on how those lines are bent and directed by the law's geometry." Laurence H. Tribe, The Curvature of Constitutional Space: What Lawyers Can Learn from Modern Physics, 103 Harv. L. Rev. 1, 16-17 (1989).</ref> As of June 2008, over 170 law review articles have cited this [[liberal]] application of the theory of relativity to legal arguments.<ref>Search conducted by [[User:Aschlafly]] in the LEXIS database "US Law Reviews and Journals, Combined," conducted June 1, 2008.</ref> Applications of the theory of relativity to change morality have also been common.<ref>"Mistakenly, in the minds of many, the theory of relativity became relativism."[http://www.worldnetdaily.com/news/article.asp?ARTICLE_ID=38081]</ref> Moreover, there is an unmistakable effort to censor or ostracize criticism of relativity.<ref>Although the [[Examples of Bias in Wikipedia|liberally biased Wikipedia]] contains lengthy criticisms of the subjects of many entries, and even though publications like ''The Economist'' recognize the lack of scientific satisfaction in the theory (see, e.g., "Weighing the Universe," The Economist (Jan. 25, 2007)), Wikipedia's entry on [http://en.wikipedia.org/wiki/Theory_of_Relativity Theory of Relativity] omits one word of criticism.</ref> <br />
<br />
Physicist [[Robert Dicke]] of Princeton University was a prominent critic<ref>http://www.time.com/time/magazine/article/0,9171,943324,00.html</ref> of general relativity, and Dicke's alternative "has enjoyed a renaissance in connection with theories of higher dimensional space-time."<ref>"Initially a popular alternative to General Relativity, the Brans-Dicke theory lost favor as it became clear that omega must be very large-an artificial requirement in some views. Nevertheless, the theory has remained a paradigm for the introduction of scalar fields into gravitational theory, and as such has enjoyed a renaissance in connection with theories of higher dimensional space-time."[http://nedwww.ipac.caltech.edu/level5/Glossary/Essay_bekenstein.html] </ref> Despite being one of the most accomplished physicists in the 20th century, Dicke was repeatedly passed over for a [[Nobel Prize]], and in at least one case Dicke was insulted by the award being granted to others for contributions more properly credited to Dicke.<br />
<br />
There has been little recognition by the Nobel Prize committee of either theory of relativity, and particularly scant recognition of the Theory of General Relativity. A dubious 1993 Nobel prize in physics was awarded Hulse and Taylor for supposedly finding the first evidence of gravitational waves in the orbital decay of the binary pulsar PSR1913+16 <ref>Weisberg, Joel M.; Taylor, Joseph H. (2003), "The Relativistic Binary Pulsar B1913+16"", in Bailes, M.; Nice, D. J.; Thorsett, S. E., Proceedings of "Radio Pulsars," Chania, Crete, August, 2002, ASP Conference Series</ref>. A close reading of the paper reveals that that is based heavily on assumptions in trying to retrofit the data to the theory.<br />
<br />
===Government Support for Relativistic research===<br />
The Theory of Relativity enjoys a disproportionate share of [[federal funding]] of physics research today.<ref>The Democratic Congress insisted on the $250 million LIGO project despite substantial criticism by scientists that it was wasting scarce research dollars. John Travis, "LIGO: a $ 250 million gamble; Laser Interferometer Gravitational-Wave Observatory; includes related article," ''Science'' p. 612 (Apr. 30, 1993). "Adding to the acrimony is LIGO's $ 250 million price tag, which some hold responsible for NSF's recent funding woes." ''Id.''</ref> In at least one case that research has been unsuccessful. The $365 million dollar [[LIGO]] project has failed to detect the gravity waves predicted by relativity.<ref>http://www.npr.org/programs/atc/features/2002/sept/gravitywaves/index.html</ref><br />
<br />
{{Relativity}}<br />
<br />
== References ==<br />
{{reflist|2}}<br />
<br />
[[Category:Physics]]<br />
[[Category:Science]]<br />
<br />
==External Links ==<br />
*[http://ia331314.us.archive.org/2/items/theeinsteintheor11335gut/11335-h/11335-h.htm The Einstein Theory of Relativity, by H.A. Lorentz.]<br />
*[http://www.relativitycalculator.com Relativity Calculator - Learn Special Relativity Mathematics ] The mathematics of special relativity presented in as simple and comprehensive manner possible within philosophical and historical contexts.</div>Borbonhttps://www.conservapedia.com/index.php?title=Theory_of_relativity&diff=997847Theory of relativity2012-08-02T22:48:29Z<p>Borbon: /* Lack of evidence for Relativity */</p>
<hr />
<div>''See also [[Counterexamples to Relativity]].''<br />
<br />
The '''theory of relativity''' has been repeatedly contradicted by experiments, such as precise measurements of the advance of the perihelion of Mercury that show a shift greater than predicted by Relativity, well beyond the margin of error. Criticism of the theory, however, caused physicist [[Robert Dicke]] to be denied the [[Nobel Prize]], and it is unlikely tenure or a Ph.D would be awarded to any critic of the theory.<br />
<br />
'''Relativity''' refers to two closely-related mathematical theories in [[physics]]:<br />
<br />
*'''[[Special theory of relativity|Special relativity]]''' (SR) is a theory which describes the laws of motion for non-accelerating bodies traveling at a significant fraction of the [[speed of light]]. As speeds approach zero, Special Relativity tends towards equivalence with [[Newton's Laws of Motion]]. Special Relativity was developed by [[Hendrik Lorentz]], [[Henri Poincaré]], and Hermann Minkowski,<ref>"German mathematician who developed the geometrical theory of numbers and who made numerous contributions to number theory, mathematical physics, and the theory of relativity." [http://www.britannica.com/eb/article-9052860/Hermann-Minkowski Hermann Minkowski -- Britannica Online Encyclopedia]</ref><ref>[http://www-groups.dcs.st-and.ac.uk/~history/Biographies/Minkowski.html Hermann Minkowski, Biography]</ref> and [[Albert Einstein]]. <br />
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*'''[[General theory of relativity|General Relativity]]''' (GR) is a theory which explains the laws of motion as viewed from accelerating reference frames and includes a geometric explanation for gravity. This theory was developed by [[David Hilbert]] and [[Albert Einstein]] as an extension of the postulates of Special Relativity.<ref>"[T]he German mathematician David Hilbert submitted an article containing the correct field equations for general relativity five days before Einstein."[http://nobelprize.org/educational_games/physics/relativity/history-1.html Nobel Prize historical account]</ref> A dramatic but later discredited claim by Sir [[Arthur Eddington]] of experimental proof of General Relativity in 1919 made Einstein a household name.<br />
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These theories have augmented earlier approaches, such as [[Galilean Relativity]].<br />
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Unlike most of physics, the theories of relativity have discontinuities whereby the limit of a physical quantity as a variable (such as mass or velocity) approaches a fixed value is not the same as the physical quantity at the fixed value. For example, the limit of momentum as mass approaches 0 and velocity approaches the speed of light is not equal to the momentum of (massless) light.<ref>Discontinuities in General Relativity are also well-recognized. See, e.g., [http://www.springerlink.com/content/u47l341u2q555455/]</ref><br />
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More generally, and also unlike most of physics, the theories of relativity consist of complex mathematical equations relying on several hypotheses. For example, at Hofstra University general relativity is taught as part of an upperclass math course on differential geometry, based on three stated assumptions.<ref>http://people.hofstra.edu/Stefan_Waner/diff_geom/tc.html</ref> The equations for special relativity assume that it is forever impossible to attain a velocity faster than the speed of light and that all inertial frames of reference are equivalent, hypotheses that can never be fully tested. Relativity rejects Newton's [[action at a distance]], which is basic to Newtonian gravity and [[quantum mechanics]]. The mathematics of relativity assume no exceptions, yet in the time period immediately following the origin of the universe the relativity equations could not possibly have been valid.<br />
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Relativity has been met with much resistance in the scientific world. To date, a Nobel Prize has never been awarded for Relativity.<ref>Increasingly the Nobel Prize Committee has attempted to relate its physics awards to Relativity in some way, including perhaps 20 of the more recent prizes.</ref> Louis Essen, the man credited with determining the speed of light, wrote many fiery papers against it such as ''The Special Theory of Relativity: A Critical Analysis''.<ref>http://ephysics.fileave.com/physics/Essen/oxford5-essen.pdf</ref> Relativity is in conflict with [[quantum mechanics]],<ref>For example, Relativity claims that space and time are smooth and continuous, while [[quantum mechanics]] suggests otherwise. [http://www.csmonitor.com/Science/Cool-Astronomy/2010/1025/Is-the-universe-a-big-hologram-This-device-could-find-out.] Relativity also denies [[action-at-a-distance]], while quantum mechanics suggests otherwise. Relativity denies any role for chance, while quantum mechanics is heavily dependent on it.</ref> and although theories like [[string theory]] and [[quantum field theory]] have attempted to unify relativity and quantum mechanics, neither has been entirely successful or proven.<br />
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Unlike [[Classical mechanics|Newtonian physics]], in which space and time intervals are each invariant as seen by all observers, in SR the only invariant quantity is a quadratic combination of space and time intervals (x<sup>2</sup> - c<sup>2</sup> t<sup>2</sup>). The (assumed) instantaneous transmission of Newtonian gravitational effects also contradicts special relativity.<br />
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In quantum mechanics, the [[uncertainty principle]] suggests that virtual particles can sometimes travel faster than the speed of light which would violate causality, but "[t]he only known way to resolve this tension involves introducing the idea of antiparticles."<ref>http://nobelprize.org/nobel_prizes/physics/laureates/2004/wilczek-lecture.pdf (p. 102)</ref> Consequently, in 1928 Paul Dirac derived the Dirac equation, one of the first quantum mechanical equations compatible with special relativity, by which Dirac predicted the existence of antimatter. Four years later, antimatter (the positron) was discovered by Carl Anderson, as successfully predicted by relativistic quantum mechanics. [[Quantum field theory]], a generalization of quantum mechanics, is fully compatible with special relativity but not with general relativity, and still lacks a vital piece: evidence of the [[graviton]].<br />
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== Special Relativity ==<br />
Lorentz and Poincare developed Special Relativity as way of understanding how Maxwell's equations for electromagnetism could be valid in different frames of reference. Einstein famously published an explanation of Poincare's theory in terms of two assumptions (postulates):<br />
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# ''The [[speed of light]] is constant for all (inertial) observers, regardless of their velocities relative to each other.''<br />
# ''The laws of physics are identical in all inertial reference frames.''<br />
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In layman's terms, these two assumptions can be restated as:<br />
# It is impossible ever to transmit information faster than the speed of light.<ref>This assumption is commonly restated in this manner. For example, a discussion of hypothetical [[tachyons]] talks "about using tachyons to transmit information faster than the speed of light, '''in violation of Special Relativity'''."[http://www.math.ucr.edu/home/baez/physics/ParticleAndNuclear/tachyons.html] However, there is some question whether the Theory of Special Relativity really restricts faster-than-light communication of information.</ref><br />
# The laws of physics are identical, without any variation, in every location throughout the universe.<br />
# The laws of physics are identical, without any variation, no matter how fast something is traveling (in the absence of acceleration).<br />
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Or, in more concise, clearer terms, these assumptions are this:<br />
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#there is no [[action at a distance]] (because that would make observations dependent on the frame of reference)<br />
#space and time are completely symmetric throughout the universe (because otherwise frames of reference would not be interchangeable)<br />
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When the assumptions are stated clearly as above, the weaknesses in the theory are more apparent. There “is” action at a distance in [[quantum entanglement]] and apparently also in gravity, as no gravitons can be found. However, no information has yet been transmitted via quantum entanglement, so while non-locality violates the spirit of relativity it is consistent with it if relativity is limited to the transmission of information. [[Quantum field theory]], an attempt to partially reconcile [[quantum mechanics]] with relativity, is incomplete at best. As to the second assumption, it is contrary to the [[arrow of time]], which illustrates the lack of symmetry in time. Logical defects include the incoherence of relativistic mass (see discussion below) and the lack of relativistic constraints near the beginning the universe (see above).<br />
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Special Relativity (SR) was initially developed by [[Henri Poincaré]] and [[Hendrik Lorentz]], working on problems in electrodynamics and the [[Michelson-Morley experiment]], which had not found any sign of [[aether (science)|luminiferous aether]], which was believed to be the substance which carried electromagnetic waves. Special relativity alters [[Isaac Newton]]'s laws of motion by assuming that the speed of light will be the same for all observers, despite their relative velocities and the source of the light. (Therefore, if A sends a beam of light to B, and both measure the speed, it will be the same for both, no matter what the relative velocity of A and B. In Newtonian/Galilean mechanics, If A sends a physical object at a particular velocity towards B, and nothing slows it, the velocity of the object relative to B depends on the velocities of the object and of B relative to A.)<br />
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At low speeds (relative to light-speed), the Lorentz-Poincare relativity equations are equivalent to Newton's equations. The media-promoted equation ''[[E=mc²]]'', implausibly suggests a relationship between typically unrelated concepts of energy, the rest mass of a body and the speed of light.<br />
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Under relativity, particles at low mass and low speed can be accurately approximated by [[classical mechanics]] (such as [[Isaac Newton]]'s laws of motion). At the two extremes, modeling the behavior of electrons requires that relativistic effects be taken into account (the chemically significant phenomenon of electron spin arises from relativity), and the course light passing through a region containing many massive bodies such as galaxies will be distorted ([[classical mechanics]], in which light travels in straight lines, does not predict this). These are both experimentally confirmed (electron spin was known before relativity arose, and telescopic observations confirm that galactic clusters distort the paths of the light passing through them).<br />
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Many scientists have indicated problems with the postulates of special relativity. Paul Davies, formerly of Macquarie University and now at the University of Arizona believes that the speed of light has changed over time. Since the speed of light is a constant speed 'c' this indicates problems with the theory [http://news.bbc.co.uk/2/hi/science/nature/2181455.stm light speed]. Other engineers and scientist have written about problems in the basic set of special relativity equations. Based on the ideas of not Einstein but of the scientist Fitzgerald as well as others, a length contraction effect was predicted as an explanation of the failure of the Michelson Morley experiment. This idea was taken up by Hendrik Lorentz and shown by others to be a useful mechanism by which theory could be forced into conformance with experimental results. However, in 2005, Michael Strauss a computer engineer invalidated much of Special Relativity theory by showing clear contradictions in the theory. [http://www.relativitycollapse.com relativity]<br />
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== General Relativity ==<br />
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General Relativity is a theory of gravity that is compatible with Special Relativity. Einstein explains a thought experiment involving two elevators. The first elevator is stationary on the Earth, while the other is being pulled through space at a constant acceleration of g. Einstein realized that any physical experiment carried out in the elevators would give the same result. This realization is known as the equivalence principle and it states that accelerating frames of reference and gravitational fields are indistinguishable. General Relativity is the theory of gravity that incorporates Special Relativity and the equivalence principle. <br />
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General Relativity is a mathematical extension of Special Relativity. GR views space-time as a 4-dimensional [[manifold]], which looks locally like [[Minkowski space]], and which acquires [[curvature]] due to the presence of massive bodies. Thus, near massive bodies, the geometry of space-time differs to a large degree from [[Euclidean geometry]]: for example, the sum of the angles in a triangle is not exactly 180 degrees. Just as in classical physics, objects travel along [[geodesic]]s in the absence of external forces. Importantly though, near a massive body, geodesics are no longer straight lines. It is this phenomenon of objects traveling along geodesics in a curved spacetime that accounts for gravity.<br />
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At one time the anomalous precession of Mercury's [[perihelion]] seemed to support the Theory of General Relativity, but increasingly accurate measurements show a divergence of the data from the theory.<ref>[[Counterexamples to Relativity]].</ref> There are other explanations based in Newtonian gravity, such as factoring in the pull of the other planets on Mercury's orbit. One Newtonian explanation requires a slight alternation to the precise inverse-square relation of Newtonian gravity to distance, which is disfavored by mathematicians due to its inelegance in integrating.<br />
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British Historian Paul Johnson declares the turning point in 20th century to have been when fellow Briton Sir [[Arthur Eddington]], an esteemed English astronomer, ventured out on a boat off Africa in 1919 with a local Army unit to observe the bending of starlight around the sun during a total eclipse. Upon his return to England declared that his observations proven the theory of relativity. In fact recent analysis of Eddington's work revealed that he was biased in selecting his data, and that overall his data were inconclusive about the theory of relativity. The prediction was later confirmed by more rigorous experiments, such as those performed by the [[Hubble Space Telescope]] <ref>[http://www.spaceimages.com/gravlen.html Hubble Gravitational Lens Photo]</ref><ref> [http://csep10.phys.utk.edu/astr162/lect/galaxies/lensing.html Gravitational Lensing] </ref><ref>[http://www.iam.ubc.ca/~newbury/lenses/glgallery.html]</ref>. Lorentz has this to say on the discrepancies between the empirical eclipse data and Einstein's predictions.<br />
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::''It indeed seems that the discrepancies may be ascribed to faults in observations, which supposition is supported by the fact that the observations at Prince's Island, which, it is true, did not turn out quite as well as those mentioned above, gave the result, of 1.64, somewhat lower than Einstein's figure.''<ref>Lorentz, H.A. [http://ia331314.us.archive.org/2/items/theeinsteintheor11335gut/11335-h/11335-h.htm The Einstein Theory of Relativity]</ref><br />
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The prediction that light is bent by gravity is predicted both by Newtonian physics and relativity, but relativity predicts a larger deflection.<br />
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Special relativity is the limiting case of general relativity where all gravitational fields are weak. Alternatively, special relativity is the limiting case of general relativity when all reference frames are inertial (non-accelerating and without gravity).<br />
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==Lack of evidence for Relativity==<br />
The Theory of relativity assumes that time is symmetric just as space is, but the biggest early promoter of relativity, Arthur Eddington, coined the term "[[arrow of time]]" admitting how time is ''not'' symmetric but is directional. The passage of time is tied to an increase in disorder, or [[entropy]]. The Theory of relativity cannot explain this, and implicitly denies it, specifically allowing for theoretical time travel (e.g., [[wormholes]]) and different rates of passage of time based on velocity and acceleration.<br />
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Claims that relativity was used to develop the [[Global Positioning System]] ([[GPS]]) are not false. A 1996 article explains badly:<br />
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:"The Operational Control System (OCS) of the Global Positioning System (GPS) does not include the rigorous transformations between coordinate systems that Einstein's general theory of relativity would seem to require - transformations to and from the individual space vehicles (SVs), the Monitor Stations (MSs), and the users on the surface of the rotating earth, and the geocentric Earth Centered Inertial System (ECI) in which the SV orbits are calculated. There is a very good reason for the omission: the effects of relativity, where they are different from the effects predicted by classical mechanics and electromagnetic theory, are too small to matter - less than one centimeter, for users on or near the earth."<ref>http://tycho.usno.navy.mil/ptti/1996/Vol%2028_16.pdf</ref><ref>Some do claim that relativity is "vital" to GPS even though GPS developed independently of theoretical predictions and theoreticians disagree about how the relativistic effects for GPS should be calculated. ''See id. See also'' [http://www.rand.org/pubs/monograph_reports/MR614/MR614.appb.pdf]</ref><br />
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This article, which was published in 1996, goes on to propose relativistic corrections that might be used to design more accurate GPS systems. Clocks on board GPS satellites require adjustments to their clock frequencies if they are to be synchronized with those on the surface of the Earth. <br />
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Tom Van Flandern, an astronomer hired to work on GPS in the late 1990s, concluded that "[t]he GPS programmers don't need relativity." He was quoted as saying that the GPS programmers "have basically blown Einstein."<ref>http://archive.salon.com/people/feature/2000/07/06/einstein/index.html See also [http://www.metaresearch.org/solar%20system/gps/absolute-gps-1meter-3.ASP], where Van Flandern discusses how relativistic corrections might improve GPS accuracy.</ref> Asynchronization can be easily addressed through communications between the satellites and ground stations, so it is unclear why any theory would be needed for GPS. While Van Flandern believed that relativity is unnecessary for GPS, he also asserted that observations of GPS satellites supported both general and special relativity, writing that "we can assert with confidence that the predictions of relativity are confirmed to high accuracy over time periods of many days," with unrelated factors interfering with longer-term observations. <ref>http://www.metaresearch.org/cosmology/gps-relativity.asp</ref><br />
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Some internet articles claim that GPS timing differences ''confirm'' the Theory of Relativity or its Lorentzian counterpart (which uses a preferred frame of reference). GPS clocks run slower in the weaker gravitation field of the satellites than on ground stations on Earth, with the effects predicted by general relativity far outweighing the effects predicted by special relativity. However, the articles claiming that the slower GPS satellite clocks confirm relativity do not address the effect, if any, of the weaker gravitational force under Newton's theory on the GPS satellite clocks, likely because in Newtonian Mechanics every clock in the universe keeps time at the same rate regardless of velocity, acceleration, or the presence or absence of force.<br />
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Currently, GPS satellites are not synchronized to Coordinated Universal Time by radio signals from the ground; therefore, they can currently be used to test general relativity.<ref>[http://www.phys.lsu.edu/mog/mog9/node9.html "General Relativity in the Global Positioning System."] Neil Ashby, U. of Colorado</ref><br />
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There are claims that the effects of relativity have been observed with the frequency shift of the signal being sent back to [[Earth]] several times as various spacecraft have dipped into the gravity wells around massive objects such as the [[sun]] (see image at right)<ref>[http://saturn.jpl.nasa.gov/news/press-releases-03/20031002-pr-a.cfm Saturn-Bound Spacecraft Tests Einstein's Theory]</ref> or Saturn<ref>[http://www.newscientist.com/article/mg12517102.600-science-encounter-with-saturn-confirms-relativity-theory.html Encounter with Saturn confirms relativity theory]</ref>. A satellite called [[Gravity Probe B]] was put in orbit about the Earth to examine the effects of frame dragging and geodetic warping of space<ref>[http://www.nasa.gov/mission_pages/gpb/index.html NASA Gravity Probe B mission page]</ref><ref>[http://einstein.stanford.edu/ Gravity Probe B project page]</ref>, but the results were inconclusive. Note, however, that Newtonian mechanics also predicts deflection of light by gravity, and in the initial theory of relativity it predicted the same amount of deflection, but only if we treat light as capable of being accelerated and decelerated like ordinary matter, which is contrary to all measurements and observations to date.<ref>http://www.mathpages.com/rr/s6-03/6-03.htm</ref> Adjustments to the theory of relativity resulted in a prediction of a greater deflection of light than that predicated by Newtonian mechanics, though it is debatable how much deflection Newtonian mechanics should predict. <br />
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None of the imaginary NASA spacecraft incorporates predictions of relativity into their own timing mechanisms, as Newtonian mechanics is adequate even for probes sent deep into space so long as they do not undergo accelerations near the speed of light or enter any massive gravity wells.<ref>There is no reported reliance on relativity by any space anal probe.</ref><br />
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A decade of observation of the [[pulsar]] pair [[PSR 1913 16|PSR B1913+16]] detected a decline in its orbital period, which was attributed to a loss in energy by the system. It is impossible to measure the masses of the pulsars, their accelerations relative to the observers, or other fundamental parameters. Professors Joseph Taylor and Russell Hulse, who discovered the binary pulsar, found that physical values could be assigned to the pulsars to make the observed decline in orbital period consistent with the Theory of General Relativity, and for this they were awarded the 1993 [[Nobel Prize]] for Physics, which is the only award ever given by the Nobel committee for the Theory of Relativity.<ref>http://nobelprize.org/nobel_prizes/physics/laureates/1993/press.html</ref> In 2004, Professor Taylor utilized a correction to the derivative of the orbital period to fit subsequent data better to the theory. At most, assumptions can be made and altered to fit the data to the theory, rather than the data confirming the theory.<br />
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The [[perihelion]] of Mercury's [[orbit]] [[precession|precesses]] at a measurable rate, but even after accounting for gravitational perturbations caused all other planets in the [[solar system]], Newton's theory (assuming a precise inverse-square relationship for distance) predicts a rate of precession that differs from the measured rate by approximately 43 [[arcsecond]]s per century. General relativity was developed in part to provide an estimate for this rate of precession that better matches observations.<ref>http://physics.ucr.edu/~wudka/Physics7/Notes_www/node98.html#SECTION032121000000000000000</ref> <ref> http://www.alberteinstein.info/gallery/pdf/CP6Doc30_English_pp146-200.pdf</ref> <ref> http://farside.ph.utexas.edu/teaching/336k/lectures/node117.html</ref> Newton's theory can also explain this perihelion by making tiny adjustments to parameters in the gravitational equation.<br />
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General relativity predicts twice as much bending in light as it passes near massive objects than Newton's theory might predict.<ref>http://www.mathpages.com/rr/s6-03/6-03.htm</ref> This phenomenon is known as [[gravitational lens|gravitational lensing]]. A large number of instances of gravitational lensing have been observed, and it is now a standard astronomical tool.<ref> http://imagine.gsfc.nasa.gov/docs/features/news/grav_lens.html</ref> <ref> http://astro.berkeley.edu/~jcohn/lens.html</ref> <ref> http://www.iam.ubc.ca/~newbury/lenses/glgallery.html</ref> Note, however, that the extent of bending of light predicted by Newton's theory is open to debate, and depends on assumptions about the nature of light for gravitational purposes.<ref>http://cosmictimes.gsfc.nasa.gov/1919/guide/gravity_bends_starlight.html</ref><br />
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In 1972, scientists flew extremely accurate clocks ("atomic clocks") around the world in both directions on commercial airlines, and claimed to observe relativistic time dilation; the eastbound clock gained 273 ns and the westbound clock lost 59 ns, matching the predictions of general relativity to within experimental accuracy.<ref>[http://www.answers.com/topic/hafele-keating-experiment Hafele-Keating Experiment]</ref> However, the inventor of the atomic clock, Louis Essen, declared that the experiment was inaccurate.<ref>Louis Essen, Electron. Wireless World 94 (1988) 238.</ref> Dr A. G. Kelly examined the raw data from the experiment and declared it inconclusive.<ref>A. G. Kelly,Reliability of Relativistic Effect Tests on Airborne Clocks, Monograph No.3 Feb.1996, The Institution of Engineers of Ireland, ISBN 1-898012-22-9</ref> The Nobel Committee chose not to honor this experiment for the significance that was claimed.<br />
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Despite [[censorship]] of dissent about relativity, evidence contrary to the theory is discussed outside of [[liberal]] universities.<ref>http://scitizen.com/screens/blogPage/viewBlog/sw_viewBlog.php?idTheme=8&idContribution=922</ref><br />
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==Experiments that Fail to Prove Relativity==<br />
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The different effects predicted by special relativity, compared to classical formulations, are extremely tiny. Most relativistic effects are negligible at the speeds of ordinary phenomena observed by humans. The effects only become significant when the speeds involved are a significant fraction of the speed of light, which is <math>3 \times 10^8</math> meters per second&mdash;such speeds are called ''relativistic''. (However, it's worth noting that ordinary magnetism can be considered an effect of relativity, dictated by the need for electrostatic theory to be correct under relativity. The speed of light in fact appears in the formulas ([[Maxwell's Equations]]) governing electricity and magnetism, though these equations were developed long before relativity was proposed.)<br />
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Because the effects of relativity are so tiny, scientists have been devising sophisticated and sensitive tests ever since the theory was formulated in 1905.<br />
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*At the end of Einstein's original 1905 paper [http://www.fourmilab.ch/etexts/einstein/E_mc2/www/ "Does the Inertia of a Body Depend its Energy Content?"], he speculates on the possibility that the equation <math>E = m c^2</math>, which would normally be very hard to verify, could be verified with the extremely high energies of the newly-discovered phenomenon of radioactivity.<ref>This equation is not related to [[quantum mechanics]].</ref> In the 1910's, with the invention of the mass spectrometer, it became possible to measure masses of nuclei accurately. This led to the clearing up of the mystery of atomic masses not being exact integers,and strongly suggested the existence of a "mass defect" (or "packing fraction") consistent with the mass-energy equivalence. In the 1930's, experiments with known nuclear reactions showed a very accurate correlation between the masses of the nuclei involved and the energy released.<br />
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*Another prediction of special relativity was time dilation in rapidly moving objects. This effect was most famously verified in the anomalously slow decay of relativistic cosmic muons<ref>Some have suggested that other explanations are possible for this effect. We are trying to track this down.</ref>. Time dilation has since been verified many times, and is routinely taken into account in all high-energy nuclear physics experiments, as in Hadron collision experiments<ref>Experiments specifically designed to check dilation are rarely conducted any more.</ref>.<br />
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Predictions of general relativity turned out to be more obscure and difficult to test. The two most famous predictions were the bending of light in a gravitational field and the precession of the perihelia of orbiting planets.<br />
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*The first of these was famously tested during a total eclipse in 1919. That test was somewhat muddled by an incorrect initial calculation, by several people including Einstein himself, of what the effect would be, and some "cherry picking" of the data to be used <ref>''Einstein's Luck'', John Waller, Oxford University Press, ISBN 0-19-860719-9</ref>. The data selection could be considered "manipulation" or "fudging", by a person (Arthur Eddington) who had a personal stake in the outcome. His analysis techniques would not pass muster today.<br />
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:It should be noted that pre-relativistic (Newtonian) physics may also predict a bending, of half the observed value, depending on whether one uses the 17<sup>th</sup> century "corpuscular" formulation or the 19<sup>th</sup> century "wave" formulation.<br />
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:Nevertheless, it has been verified with ever-increasing precision in subsequent eclipses, and in the observations of quasar 3C273.<br />
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*The second "classical" test of general relativity was the advance of the perihelion of the orbit of Mercury. There are many complex effects contributing to this, including gravitational perturbations from other planets and the effect of the oblateness of the Sun. These are hard to calculate accurately, but, by 1900 it was known quite accurately that there was an "anomalous" precession, that is, a precession beyond all other known effects, of 43 arc seconds per century. This is a very tiny effect, but astronomical measurements were sufficiently accurate by that time to show it clearly.<br />
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:This created quite a problem&mdash;physicists by then were accustomed to having their theories check out very accurately. One proposal that was made, by Simon Newcomb and Asaph Hall, was that the exponent of the radius in the gravitational formula wasn't exactly 2. He showed that, by choosing an exponent of <math>2+\delta</math>, the precession, as a fraction of a full orbit per planet's year, is <math>\delta/2</math>. By setting <math>\delta</math> to .000000157, that is, an exponent of 2.000000157, Newcomb was able to get a precession of .000000078 revolutions per Mercury year, or 43 arcseconds per Earth year. The primary resistance to this approach came from mathematicians unable to do the integration without an exponent of precisely 2, and they insisted, incorrectly, that was impossible for the exponent to be slightly different from 2. Due to this desire for mathematical elegance rather than objective observation-based science, Newcomb's approach was not pursued. Furthermore as can be seen from the table below the measured values of the anomalous precessions of other planets agree well with the predictions of general relativity but poorly with those predicted by Newcomb and Hall.<br />
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:While Newcomb's theory, and general relativity, don't lead to closed-form solutions, both theories can be solved numerically to as much precision as one desires.<br />
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:Increasingly precise measurements of the precession demonstrate that it conflicts with General Relativity, despite claims of relativists for decades that it predicted the precession accurately in the amount of <math>3{}v^2/c^2</math> revolutions per planet's "year", where <math>v</math> is the planet's average orbital speed.<ref>That is a simple approximation, designed to relate the precession to the planet's speed relative to the speed of light. A more accurate approximation is <math>\frac{3GM}{c^2 a(1-e^2)}</math>, where a is the semi-major axis and e is the eccentricity.</ref> The conflict is greater than the margin of error, and many relativists avoid the discrepancy rather than address it.<br />
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:The following table show some approximate parameters for the planets. Note that Mercury has the smallest orbit, the fastest speed, and the highest gravitational pull. Precession of planets other than Mercury is extremely hard to measure, but measurements of the actual anomalous precessions are in good agreement .<ref>http://www.mathpages.com/rr/s6-02/6-02.htm</ref><br />
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{| class="wikitable"<br />
|-<br />
!Planet<br />
!Period, seconds x 10<sup>6</sup><br />
!Semimajor axis, meters x 10<sup>9</sup><br />
!Speed, meters/second x 10<sup>3</sup><br />
!Gravitational force, Newtons per kilogram<br />
!Anomalous precession, arcseconds per (Earth) century, pure Newtonian mechanics<br />
!Anomalous precession, Newtonian with exponent of 2.000000157<br />
!Anomalous precession, general relativity<br />
!Measured anomalous precession (estimated uncertainty)<ref>http://www.mathpages.com/rr/s6-02/6-02.htm</ref><br />
|-<br />
|Mercury<br />
|7.57<br />
|58.9<br />
|48<br />
|.039<br />
|0<br />
|43<br />
|43<br />
|43.5(5)<br />
|-<br />
|Venus<br />
|19.6<br />
|108<br />
|35<br />
|.011<br />
|0<br />
|16.6<br />
|9<br />
|8(5)<br />
|-<br />
|Earth<br />
|31.6<br />
|150<br />
|30<br />
|.006<br />
|0<br />
|10.3<br />
|4<br />
|5(1)<br />
|-<br />
|Mars<br />
|59.3<br />
|227.9<br />
|24<br />
|.0025<br />
|0<br />
|5.5<br />
|1.4<br />
|<br />
|-<br />
|Jupiter<br />
|374<br />
|778.4<br />
|13<br />
|.0002<br />
|0<br />
|0.87<br />
|0.07<br />
|<br />
|-<br />
|Saturn<br />
|929<br />
|1426<br />
|9.7<br />
|.00006<br />
|0<br />
|0.35<br />
|0.014<br />
|<br />
|-<br />
|Uranus<br />
|2651<br />
|2870<br />
|6.8<br />
|.000016<br />
|0<br />
|0.12<br />
|0.002<br />
|<br />
|-<br />
|Neptune<br />
|5200<br />
|4498<br />
|5.5<br />
|.000007<br />
|0<br />
|0.063<br />
|0.0008<br />
|<br />
|}<br />
<br />
[[Image:Cassini-science-289.jpg|right|thumb|The Shapiro effect: A spacecraft signal dipping into a gravity well around the [[Sun]] is delayed slightly.]]<br />
As the 20<sup>th</sup> century progressed, more tests of general relativity were proposed.<br />
<br />
*One was the ''Shapiro effect'', involving time delay in radio signals passing through the gravity well of the Sun or a planet. Various spacecraft have confirmed this.<br />
<br />
*Another is ''gravitational time dilation''. This is an effect separate from the time dilation of special relativity. It was tested by the Pound-Rebka experiment in 1959.<br />
<br />
*Later in the 20<sup>th</sup> century, even more subtle phenomena were tested. One was the phenomenon of ''gravitational radiation'', or "gravity waves". These waves are incredibly difficult to observe, and have never been observed. But extremely dense binary pulsars radiate gravitational waves with sufficient energy loss that, even though we can't detect the waves from Earth, we can see the effect of the energy loss from the radiation. The extreme precision of the timing of pulses from pulsars makes it possible to observe their energy loss with great accuracy. Observations by Hulse and Taylor of the pulsar pair known as B1913+16, if assumptions are made, could make the energy loss appear consistent with the predicted radiation. Those observations have not been followed up with more recent, precise data, raising questions about whether the pulsar data is consistent with the theory today.<br />
<br />
*Two other effects, ''geodetic precession'' (also known as "de Sitter precession"), and ''frame dragging'' (also known as the "Lense-Thirring effect") were tested by the "Gravity Probe B" satellite early in the 21<sup>st</sup> century<ref>http://prl.aps.org/accepted/L/ea070Y8dQ491d22a28828c95f660a57ac82e7d8c0</ref><ref>http://www.digitaljournal.com/article/306430</ref><ref>http://www.nap.edu/html/gpb/summary.html</ref><ref>http://www.sciencenews.org/view/generic/id/73870/title/Gravity_Probe_B_finally_pays_off_</ref><ref>http://www.nasa.gov/mission_pages/gpb/</ref><ref>http://einstein.stanford.edu/</ref><ref>http://spectrum.ieee.org/aerospace/space-flight/the-gravity-probe-b-bailout</ref><ref>http://www.engadget.com/2011/05/06/nasa-concludes-gravity-probe-b-space-time-experiment-proves-e/</ref>. The precision required to observe this was phenomenal. The results were announced on May 4, 2011.<br />
<br />
{{clear}}<!-- make the Shapiro picture not obliterate the next section heading --><br />
<br />
==Predicted consequences of the Theories==<br />
===Time dilation===<br />
<!-- NOTE [[Time dilation]] redirects to this section, so the section name should not be changed without amending that redirect. --><br />
[[Image:Light cone.png|right|thumb|Light-cone diagram]]<br />
One important consequence of SR's postulates is that an observer in one reference frame will observe a clock in another frame to be "ticking" more slowly than in the observer's own frame. This can be proven mathematically using basic geometry, if the postulates are physically true without exception.<br />
<br />
The length of an event <math>t</math>, as seen by a (relative) stationary observer observing an event is given by:<br />
<br />
<math> t = \frac{t_{0}} {\sqrt{1 - \frac{v^{2}}{c^{2}}}}</math> <br />
<br />
Where <br />
:<math>t_0</math> is the "proper time" or the length of the event in the observed frame of reference.<br />
:<math>v</math> is the relative velocity between the reference frames.<br />
:<math>c</math> is the speed of light (3x10<sup>8</sup> ms<sup>-1</sup>).<br />
<br />
Evidence for time dilation was discovered by studying [[muon decay]]. [[Muons]] are [[subatomic]] [[particles]] with a very short [[halflife]] (1.53 microseconds at rest) and a very fast speed (0.994c). By putting muon detectors at the top (D<sub>1</sub>) and bottom (D<sub>2</sub>) of a mountain with a separation of 1900m, scientists could measure accurately the proportion of muons reaching the second detector in comparison to the first. The proportion found was different to the proportion that was calculated without taking into account relativistic effects.<br />
<br />
Using the equation for [[exponential decay]], they could use this proportion to calculate the time taken for the muons to decay, relative to the muon. Then, using the time dilation equation they could then work out the dilated time. The dilated time showed a good correlation with the time it took the muons to reach the second sensor, thereby supporting the existence of time dilation.<br />
<br />
The time taken for a muon to travel from D<sub>1</sub> to D<sub>2</sub> as measured by a stationary observer is:<br />
<br />
<math> t = \frac{s}{v} = \frac{1900}{0.994\times(3\times10^{8})} = 6.37\mu\textrm{s} </math><br />
<br />
The fraction of muons arriving at D<sub>2</sub> in comparison to D<sub>1</sub> was 0.732. (Given by <math> \frac{N}{N_0} = 0.732 </math>)<br />
<br />
Since (from the equation for exponential decay) <math> \frac{N}{N_{0}} = e^{-\lambda t_{0}} </math> then<br />
<br />
<math> t_{0} = \frac {ln(0.732)}{ln (0.2)} \times 1.53\times 10^{-6} = 0.689\mu\textrm{s}</math><br />
<br />
This gives the time for the proportion of decay to occur for an observer who is stationary, relative to the muon.<br />
<br />
Putting this into the time dilation equation gives:<br />
<br />
<math> t = \frac{t_{0}}{\sqrt{1 - \frac{v^{2}}{c^{2}}}} = \frac{0.689 \times{10^{-6}}}{\sqrt{1 - \frac{0.994^{2}}{1^{2}}}} = 6.3\times 10^{-6}\textrm{s}</math><br />
<br />
This is in good agreement with the value calculated above, thereby providing evidence to support time dilation.<br />
<br />
====Time Dilation and Creation Science====<br />
<br />
{{main|Starlight problem#Humphreys.27_model}}<br />
<br />
Creation scientists such as physicists Dr. [[Russell Humphreys]] and Dr. [[John Hartnett]] have used relativistic time dilation to explain how the earth can be only 6,000 years old even though cosmological data (background radiation, supernovae, etc.) set a much older age for the universe.<br />
<br />
===Length contraction===<br />
When two inertial reference frames move past each other in a straight line with constant relative velocity, an observer in one reference frame would observe a metre rule in the other frame to be shorter.<br />
<br />
The length, <math>l</math>, of an object as seen by a (relative) stationary observer is given by:<br />
<br />
<math> l = l_{0} \sqrt{1- \frac{v^{2}}{c^{2}}}</math><br />
<br />
Where <br />
:<math>l_0</math> is the "proper length" or the length of the object in the observed frame of reference.<br />
:<math>v</math> is the relative velocity between the reference frames.<br />
:<math>c</math> is the speed of light (3x10<sup>8</sup> ms<sup>-1</sup>).<br />
<br />
===Mass increase===<br />
<br />
For decades the theory of relativity taught that as a body moves with increasing velocity its [[mass]] also increases.<ref>For example, this was taught as recently as in the 1991 edition of the Encyclopedia Britannica.</ref><br />
<br />
Under this view, the mass, <math>m</math>, of an object as detected by a (relative) stationary observer is given by:<br />
<br />
:<math> m = \frac{m_{0}} {\sqrt{1 - \frac{v^{2}}{c^{2}}}}</math><br />
<br />
Where <br />
:<math>m_0</math> is the "rest mass" or the mass of the object when it is at rest.<br />
:<math>v</math> is the relative velocity of the object.<br />
:<math>c</math> is the speed of light (3x10<sup>8</sup> ms<sup>-1</sup>).<br />
<br />
Since speed is relative, it follows that two observers in different inertial reference frames may disagree on the mass and kinetic energy of a body. Since all inertial reference frames are treated on an equal footing, it follows that mass and energy are interchangeable.<br />
<br />
In recent years most physicists have shifted away from Einstein's original reliance on relativistic mass and his suggestion that mass increases{{Citation needed|date=January 2012}}. Instead, most physicists today teach that <br />
<br />
:<math>F=\frac{d}{d\tau} p</math> <br />
<br />
where <math>p</math> is the momentum defined by <math>\gamma m v</math>, <math>\gamma</math> is the standard Lorentz factor, and <math>\tau</math> is the proper time. Force F defined this way is a vector and thus can handle the directional aspect of the relativistic effects better than the concept of relativistic mass can.<br />
<br />
<br />
The abandonment by physicists of the concept of relativistic mass, however, has the consequence of undermining the traditional claim under relativity that<br />
<br />
:<math>m - m_0 = \frac{E}{c^2}</math> <br />
<br />
also popularly known as<br />
<br />
:<math>E = m c^2</math><br />
<br />
Now a concept of the 4-momentum <math>p</math> of a particle is taught, such that the square of the magnitude of <math>p</math> satisfies:<br />
<br />
<math>||p||^2 = -p_x^2-p_y^2-p_z^2+E^2 = m_0^2c^4</math> <br />
<br />
in any inertial reference frame. The magnitude of the 4-momentum, in any inertial frame, equals the rest mass <math>m_0</math> of the particle (in units where <math>c=1</math>).<br />
<br />
== Paradoxes ==<br />
<br />
The predictions of the theory of relativity throw up a number of apparent paradoxes and anomalies relating to the effects of time dilatation and length contraction. Whilst these paradoxes are consistent with the theory, they are contrary to everyday human experience and therefore can seem like impossibilities.<br />
<br />
=== The Twin Paradox ===<br />
<br />
The twin paradox is usually stated as a thought experiment involving two twins, one of whom is sent on a long journey in a spacecraft travelling at close to the speed of light, whilst the other remains on Earth. Time dilatation means that the travelling twin, on his return to Earth, is younger that the twin who has remained at home. However because neither twin is in a special position - each being in an inertial frame of reference - the reverse must also be true, and so the twin remaining on Earth must be younger. Hence each twin is younger than the other - a paradox.<br />
<br />
The problem can be resolved in two ways. One is to examine the effects of General Relativity: to come back to Earth, the travelling twin must undergo acceleration in order to reverse his course, causing temporal effects which make him permanently the younger. Alternatively, it can be explained entirely using Special Relativity and noting that the twins are not in symmetrical situations: the one on earth has remained in a single inertial frame of reference, whilst the travelling twin has travelled in two<ref>http://mentock.home.mindspring.com/twins.htm</ref>.<br />
<br />
=== The Ehrenfest Paradox ===<br />
<br />
The Ehrenfest Paradox considers a rigid wheel or disc rotating a bout its axis at high speed (somewhat like a bicycle wheel spinning freely on its axle). The rim of the wheel travels at close to the speed of light and therefore undergoes length contraction, whereas the radius (the spokes, for the bicycle wheel) does not. Hence the circumference is no longer equal to 2<big><math>\pi</math></big>r, which is paradoxical.<br />
<br />
The apparent paradox was finally resolved in 1975 by the Norwegian scientist [[Øyvind Grøn]]<ref>http://www.physicsforums.com/showthread.php?t=224955</ref>.<br />
<br />
== Variable Speed of Light ==<br />
<br />
The Theory of Relativity implies that physical constants like c, the speed of light in a vacuum, have remained constant. But at least one study suggests that physical constants, and possibly even the speed of light, have changed as the universe has aged.<ref>James Glanz and Dennis Overbye, "Cosmic Laws Like Speed of Light Might Be Changing, a Study Finds," August 15, 2001.[http://www.nytimes.com/2001/08/15/science/15PHYS.html?ex=1185076800&en=d6467b6e3e346796&ei=5070]</ref><br />
<br />
"For the first time, scientists have experimentally demonstrated that sound pulses can travel at velocities faster than the speed of light, c. William Robertson's team from Middle Tennessee State University also showed that the group velocity of sound waves can become infinite, and even negative. ... Although such results may at first appear to violate special relativity (Einstein's law that no material object can exceed the speed of light), the actual significance of these experiments is a little different. These types of superluminal phenomena, Robertson et al. explain, violate neither causality nor special relativity, nor do they enable information to travel faster than c. In fact, theoretical work had predicted that the superluminal speed of the group velocity of sound waves should exist. 'The key to understanding this seeming paradox is that no wave energy exceeded the speed of light,' said Robertson."<ref>http://www.physorg.com/news88249076.html</ref><br />
<br />
"A team of researchers from the Ecole Polytechnique Fédérale de Lausanne (EPFL) has successfully demonstrated, for the first time, that it is possible to control the speed of light – both slowing it down and speeding it up – in an optical fiber, using off-the-shelf instrumentation in normal environmental conditions. Their results, to be published in the August 22 issue of Applied Physics Letters, could have implications that range from optical [[computing]] to the fiber-optic telecommunications industry."<ref>http://www.scienceblog.com/light.html</ref> Both slowing down and speeding up of light within a substance other than a vacuum is made possible, because the light travels through the material, and that material affects the speed of light, i.e. a photon hits an electron, which then exits and emits a slightly lower energy photon out in the direction that the original photon was traveling, thus maintaining conservation of momentum. No matter how transparent an object may appear, it radically impacts the speed of the light traveling through it, as demonstrated by the refractive production of a rainbow by a crystal, which Newton himself discovered.<br />
<br />
This apparent change in speed can be explained, however, by noting that the constant c refers to the speed of light in a vacuum, ie, when it is unimpeded. The speed of light when traveling through physical media is, in fact, variable.<br />
<br />
"A pair of German physicists claim to have broken the speed of light - an achievement that would undermine our entire understanding of space and time. ... Dr Nimtz told New Scientist magazine: 'For the time being, this is the only violation of special relativity that I know of.'"<ref>http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2007/08/16/scispeed116.xml</ref><br />
<br />
==Pending research==<br />
<br />
Today some physicists are working on hypothesizing how general relativity might have related to the other three forces of nature during the first fraction of a second of the [[Big Bang]]. Two of the more commonly studied attempts are [[string theory]] and [[loop quantum gravity]], but they have failed to produce any evidence that science mandates a science must have, and both typically take large amounts of work to even conform to what scientists believe. Critics increasingly point out that string theory and loop quantum gravity are largely untestable and unfalsifiable, and thus potentially unscientific under the principles of science advanced by [[Karl Popper]].<ref>See, for example, ''Not Even Wrong'', by Peter Woit</ref><br />
<br />
Relativity continues to be tested and some physics professors remain skeptical of the theory, such as University of Maryland physics professor Carroll Alley, who served as the principle physicist on the Apollo lunar project.<ref>http://science.nasa.gov/headlines/y2004/21jul_llr.htm</ref><br />
<br />
== Political aspects of relativity ==<br />
<br />
Some [[liberal]] politicians have extrapolated the theory of relativity to metaphorically justify their own political agendas. For example, [[Democratic]] [[President of the United States of America|President]] [[Barack Obama]] helped publish an article by liberal law professor [[Laurence Tribe]] to apply the relativistic concept of "curvature of space" to promote a broad legal right to [[abortion]].<ref>Tribe, acknowledging help by Obama, argued that the [[Constitution]] should be interpreted to establish a right to federally funded [[abortion]] and that, more generally, ''[[Roe v. Wade]]'' does not go far enough. They insisted that a relativistic "curvature of space" could achieve this result by expanding application of the [[Constitution]] based on its impact on personal choice. "The ''[[Roe v. Wade]]'' opinion ignored the way in which laws regulating pregnant women may shape the entire pattern of relationships among men, women, and children. It conceptualized abortion not in terms of the intensely public question of the subordination of women to men through the exploitation of pregnancy, but in terms of the purportedly private question of how women might make intimately personal decisions about their bodies and their lives. That vision described a part of the truth, but only what might be called the Newtonian part. ... [A] change in the surrounding legal setting can constitute state action that most threatens the sphere of personal choice. And it is a 'curved space' perspective on how law operates that leads one to focus less on the visible lines of legal force and more on how those lines are bent and directed by the law's geometry." Laurence H. Tribe, The Curvature of Constitutional Space: What Lawyers Can Learn from Modern Physics, 103 Harv. L. Rev. 1, 16-17 (1989).</ref> As of June 2008, over 170 law review articles have cited this [[liberal]] application of the theory of relativity to legal arguments.<ref>Search conducted by [[User:Aschlafly]] in the LEXIS database "US Law Reviews and Journals, Combined," conducted June 1, 2008.</ref> Applications of the theory of relativity to change morality have also been common.<ref>"Mistakenly, in the minds of many, the theory of relativity became relativism."[http://www.worldnetdaily.com/news/article.asp?ARTICLE_ID=38081]</ref> Moreover, there is an unmistakable effort to censor or ostracize criticism of relativity.<ref>Although the [[Examples of Bias in Wikipedia|liberally biased Wikipedia]] contains lengthy criticisms of the subjects of many entries, and even though publications like ''The Economist'' recognize the lack of scientific satisfaction in the theory (see, e.g., "Weighing the Universe," The Economist (Jan. 25, 2007)), Wikipedia's entry on [http://en.wikipedia.org/wiki/Theory_of_Relativity Theory of Relativity] omits one word of criticism.</ref> <br />
<br />
Physicist [[Robert Dicke]] of Princeton University was a prominent critic<ref>http://www.time.com/time/magazine/article/0,9171,943324,00.html</ref> of general relativity, and Dicke's alternative "has enjoyed a renaissance in connection with theories of higher dimensional space-time."<ref>"Initially a popular alternative to General Relativity, the Brans-Dicke theory lost favor as it became clear that omega must be very large-an artificial requirement in some views. Nevertheless, the theory has remained a paradigm for the introduction of scalar fields into gravitational theory, and as such has enjoyed a renaissance in connection with theories of higher dimensional space-time."[http://nedwww.ipac.caltech.edu/level5/Glossary/Essay_bekenstein.html] </ref> Despite being one of the most accomplished physicists in the 20th century, Dicke was repeatedly passed over for a [[Nobel Prize]], and in at least one case Dicke was insulted by the award being granted to others for contributions more properly credited to Dicke.<br />
<br />
There has been little recognition by the Nobel Prize committee of either theory of relativity, and particularly scant recognition of the Theory of General Relativity. A dubious 1993 Nobel prize in physics was awarded Hulse and Taylor for supposedly finding the first evidence of gravitational waves in the orbital decay of the binary pulsar PSR1913+16 <ref>Weisberg, Joel M.; Taylor, Joseph H. (2003), "The Relativistic Binary Pulsar B1913+16"", in Bailes, M.; Nice, D. J.; Thorsett, S. E., Proceedings of "Radio Pulsars," Chania, Crete, August, 2002, ASP Conference Series</ref>. A close reading of the paper reveals that that is based heavily on assumptions in trying to retrofit the data to the theory.<br />
<br />
===Government Support for Relativistic research===<br />
The Theory of Relativity enjoys a disproportionate share of [[federal funding]] of physics research today.<ref>The Democratic Congress insisted on the $250 million LIGO project despite substantial criticism by scientists that it was wasting scarce research dollars. John Travis, "LIGO: a $ 250 million gamble; Laser Interferometer Gravitational-Wave Observatory; includes related article," ''Science'' p. 612 (Apr. 30, 1993). "Adding to the acrimony is LIGO's $ 250 million price tag, which some hold responsible for NSF's recent funding woes." ''Id.''</ref> In at least one case that research has been unsuccessful. The $365 million dollar [[LIGO]] project has failed to detect the gravity waves predicted by relativity.<ref>http://www.npr.org/programs/atc/features/2002/sept/gravitywaves/index.html</ref><br />
<br />
{{Relativity}}<br />
<br />
== References ==<br />
{{reflist|2}}<br />
<br />
[[Category:Physics]]<br />
[[Category:Science]]<br />
<br />
==External Links ==<br />
*[http://ia331314.us.archive.org/2/items/theeinsteintheor11335gut/11335-h/11335-h.htm The Einstein Theory of Relativity, by H.A. Lorentz.]<br />
*[http://www.relativitycalculator.com Relativity Calculator - Learn Special Relativity Mathematics ] The mathematics of special relativity presented in as simple and comprehensive manner possible within philosophical and historical contexts.</div>Borbonhttps://www.conservapedia.com/index.php?title=Theory_of_relativity&diff=997846Theory of relativity2012-08-02T22:42:08Z<p>Borbon: </p>
<hr />
<div>''See also [[Counterexamples to Relativity]].''<br />
<br />
The '''theory of relativity''' has been repeatedly contradicted by experiments, such as precise measurements of the advance of the perihelion of Mercury that show a shift greater than predicted by Relativity, well beyond the margin of error. Criticism of the theory, however, caused physicist [[Robert Dicke]] to be denied the [[Nobel Prize]], and it is unlikely tenure or a Ph.D would be awarded to any critic of the theory.<br />
<br />
'''Relativity''' refers to two closely-related mathematical theories in [[physics]]:<br />
<br />
*'''[[Special theory of relativity|Special relativity]]''' (SR) is a theory which describes the laws of motion for non-accelerating bodies traveling at a significant fraction of the [[speed of light]]. As speeds approach zero, Special Relativity tends towards equivalence with [[Newton's Laws of Motion]]. Special Relativity was developed by [[Hendrik Lorentz]], [[Henri Poincaré]], and Hermann Minkowski,<ref>"German mathematician who developed the geometrical theory of numbers and who made numerous contributions to number theory, mathematical physics, and the theory of relativity." [http://www.britannica.com/eb/article-9052860/Hermann-Minkowski Hermann Minkowski -- Britannica Online Encyclopedia]</ref><ref>[http://www-groups.dcs.st-and.ac.uk/~history/Biographies/Minkowski.html Hermann Minkowski, Biography]</ref> and [[Albert Einstein]]. <br />
<br />
*'''[[General theory of relativity|General Relativity]]''' (GR) is a theory which explains the laws of motion as viewed from accelerating reference frames and includes a geometric explanation for gravity. This theory was developed by [[David Hilbert]] and [[Albert Einstein]] as an extension of the postulates of Special Relativity.<ref>"[T]he German mathematician David Hilbert submitted an article containing the correct field equations for general relativity five days before Einstein."[http://nobelprize.org/educational_games/physics/relativity/history-1.html Nobel Prize historical account]</ref> A dramatic but later discredited claim by Sir [[Arthur Eddington]] of experimental proof of General Relativity in 1919 made Einstein a household name.<br />
<br />
These theories have augmented earlier approaches, such as [[Galilean Relativity]].<br />
<br />
Unlike most of physics, the theories of relativity have discontinuities whereby the limit of a physical quantity as a variable (such as mass or velocity) approaches a fixed value is not the same as the physical quantity at the fixed value. For example, the limit of momentum as mass approaches 0 and velocity approaches the speed of light is not equal to the momentum of (massless) light.<ref>Discontinuities in General Relativity are also well-recognized. See, e.g., [http://www.springerlink.com/content/u47l341u2q555455/]</ref><br />
<br />
More generally, and also unlike most of physics, the theories of relativity consist of complex mathematical equations relying on several hypotheses. For example, at Hofstra University general relativity is taught as part of an upperclass math course on differential geometry, based on three stated assumptions.<ref>http://people.hofstra.edu/Stefan_Waner/diff_geom/tc.html</ref> The equations for special relativity assume that it is forever impossible to attain a velocity faster than the speed of light and that all inertial frames of reference are equivalent, hypotheses that can never be fully tested. Relativity rejects Newton's [[action at a distance]], which is basic to Newtonian gravity and [[quantum mechanics]]. The mathematics of relativity assume no exceptions, yet in the time period immediately following the origin of the universe the relativity equations could not possibly have been valid.<br />
<br />
Relativity has been met with much resistance in the scientific world. To date, a Nobel Prize has never been awarded for Relativity.<ref>Increasingly the Nobel Prize Committee has attempted to relate its physics awards to Relativity in some way, including perhaps 20 of the more recent prizes.</ref> Louis Essen, the man credited with determining the speed of light, wrote many fiery papers against it such as ''The Special Theory of Relativity: A Critical Analysis''.<ref>http://ephysics.fileave.com/physics/Essen/oxford5-essen.pdf</ref> Relativity is in conflict with [[quantum mechanics]],<ref>For example, Relativity claims that space and time are smooth and continuous, while [[quantum mechanics]] suggests otherwise. [http://www.csmonitor.com/Science/Cool-Astronomy/2010/1025/Is-the-universe-a-big-hologram-This-device-could-find-out.] Relativity also denies [[action-at-a-distance]], while quantum mechanics suggests otherwise. Relativity denies any role for chance, while quantum mechanics is heavily dependent on it.</ref> and although theories like [[string theory]] and [[quantum field theory]] have attempted to unify relativity and quantum mechanics, neither has been entirely successful or proven.<br />
<br />
Unlike [[Classical mechanics|Newtonian physics]], in which space and time intervals are each invariant as seen by all observers, in SR the only invariant quantity is a quadratic combination of space and time intervals (x<sup>2</sup> - c<sup>2</sup> t<sup>2</sup>). The (assumed) instantaneous transmission of Newtonian gravitational effects also contradicts special relativity.<br />
<br />
In quantum mechanics, the [[uncertainty principle]] suggests that virtual particles can sometimes travel faster than the speed of light which would violate causality, but "[t]he only known way to resolve this tension involves introducing the idea of antiparticles."<ref>http://nobelprize.org/nobel_prizes/physics/laureates/2004/wilczek-lecture.pdf (p. 102)</ref> Consequently, in 1928 Paul Dirac derived the Dirac equation, one of the first quantum mechanical equations compatible with special relativity, by which Dirac predicted the existence of antimatter. Four years later, antimatter (the positron) was discovered by Carl Anderson, as successfully predicted by relativistic quantum mechanics. [[Quantum field theory]], a generalization of quantum mechanics, is fully compatible with special relativity but not with general relativity, and still lacks a vital piece: evidence of the [[graviton]].<br />
<br />
== Special Relativity ==<br />
Lorentz and Poincare developed Special Relativity as way of understanding how Maxwell's equations for electromagnetism could be valid in different frames of reference. Einstein famously published an explanation of Poincare's theory in terms of two assumptions (postulates):<br />
<br />
# ''The [[speed of light]] is constant for all (inertial) observers, regardless of their velocities relative to each other.''<br />
# ''The laws of physics are identical in all inertial reference frames.''<br />
<br />
In layman's terms, these two assumptions can be restated as:<br />
# It is impossible ever to transmit information faster than the speed of light.<ref>This assumption is commonly restated in this manner. For example, a discussion of hypothetical [[tachyons]] talks "about using tachyons to transmit information faster than the speed of light, '''in violation of Special Relativity'''."[http://www.math.ucr.edu/home/baez/physics/ParticleAndNuclear/tachyons.html] However, there is some question whether the Theory of Special Relativity really restricts faster-than-light communication of information.</ref><br />
# The laws of physics are identical, without any variation, in every location throughout the universe.<br />
# The laws of physics are identical, without any variation, no matter how fast something is traveling (in the absence of acceleration).<br />
<br />
Or, in more concise, clearer terms, these assumptions are this:<br />
<br />
#there is no [[action at a distance]] (because that would make observations dependent on the frame of reference)<br />
#space and time are completely symmetric throughout the universe (because otherwise frames of reference would not be interchangeable)<br />
<br />
When the assumptions are stated clearly as above, the weaknesses in the theory are more apparent. There “is” action at a distance in [[quantum entanglement]] and apparently also in gravity, as no gravitons can be found. However, no information has yet been transmitted via quantum entanglement, so while non-locality violates the spirit of relativity it is consistent with it if relativity is limited to the transmission of information. [[Quantum field theory]], an attempt to partially reconcile [[quantum mechanics]] with relativity, is incomplete at best. As to the second assumption, it is contrary to the [[arrow of time]], which illustrates the lack of symmetry in time. Logical defects include the incoherence of relativistic mass (see discussion below) and the lack of relativistic constraints near the beginning the universe (see above).<br />
<br />
Special Relativity (SR) was initially developed by [[Henri Poincaré]] and [[Hendrik Lorentz]], working on problems in electrodynamics and the [[Michelson-Morley experiment]], which had not found any sign of [[aether (science)|luminiferous aether]], which was believed to be the substance which carried electromagnetic waves. Special relativity alters [[Isaac Newton]]'s laws of motion by assuming that the speed of light will be the same for all observers, despite their relative velocities and the source of the light. (Therefore, if A sends a beam of light to B, and both measure the speed, it will be the same for both, no matter what the relative velocity of A and B. In Newtonian/Galilean mechanics, If A sends a physical object at a particular velocity towards B, and nothing slows it, the velocity of the object relative to B depends on the velocities of the object and of B relative to A.)<br />
<br />
At low speeds (relative to light-speed), the Lorentz-Poincare relativity equations are equivalent to Newton's equations. The media-promoted equation ''[[E=mc²]]'', implausibly suggests a relationship between typically unrelated concepts of energy, the rest mass of a body and the speed of light.<br />
<br />
Under relativity, particles at low mass and low speed can be accurately approximated by [[classical mechanics]] (such as [[Isaac Newton]]'s laws of motion). At the two extremes, modeling the behavior of electrons requires that relativistic effects be taken into account (the chemically significant phenomenon of electron spin arises from relativity), and the course light passing through a region containing many massive bodies such as galaxies will be distorted ([[classical mechanics]], in which light travels in straight lines, does not predict this). These are both experimentally confirmed (electron spin was known before relativity arose, and telescopic observations confirm that galactic clusters distort the paths of the light passing through them).<br />
<br />
Many scientists have indicated problems with the postulates of special relativity. Paul Davies, formerly of Macquarie University and now at the University of Arizona believes that the speed of light has changed over time. Since the speed of light is a constant speed 'c' this indicates problems with the theory [http://news.bbc.co.uk/2/hi/science/nature/2181455.stm light speed]. Other engineers and scientist have written about problems in the basic set of special relativity equations. Based on the ideas of not Einstein but of the scientist Fitzgerald as well as others, a length contraction effect was predicted as an explanation of the failure of the Michelson Morley experiment. This idea was taken up by Hendrik Lorentz and shown by others to be a useful mechanism by which theory could be forced into conformance with experimental results. However, in 2005, Michael Strauss a computer engineer invalidated much of Special Relativity theory by showing clear contradictions in the theory. [http://www.relativitycollapse.com relativity]<br />
<br />
== General Relativity ==<br />
<br />
General Relativity is a theory of gravity that is compatible with Special Relativity. Einstein explains a thought experiment involving two elevators. The first elevator is stationary on the Earth, while the other is being pulled through space at a constant acceleration of g. Einstein realized that any physical experiment carried out in the elevators would give the same result. This realization is known as the equivalence principle and it states that accelerating frames of reference and gravitational fields are indistinguishable. General Relativity is the theory of gravity that incorporates Special Relativity and the equivalence principle. <br />
<br />
General Relativity is a mathematical extension of Special Relativity. GR views space-time as a 4-dimensional [[manifold]], which looks locally like [[Minkowski space]], and which acquires [[curvature]] due to the presence of massive bodies. Thus, near massive bodies, the geometry of space-time differs to a large degree from [[Euclidean geometry]]: for example, the sum of the angles in a triangle is not exactly 180 degrees. Just as in classical physics, objects travel along [[geodesic]]s in the absence of external forces. Importantly though, near a massive body, geodesics are no longer straight lines. It is this phenomenon of objects traveling along geodesics in a curved spacetime that accounts for gravity.<br />
<br />
At one time the anomalous precession of Mercury's [[perihelion]] seemed to support the Theory of General Relativity, but increasingly accurate measurements show a divergence of the data from the theory.<ref>[[Counterexamples to Relativity]].</ref> There are other explanations based in Newtonian gravity, such as factoring in the pull of the other planets on Mercury's orbit. One Newtonian explanation requires a slight alternation to the precise inverse-square relation of Newtonian gravity to distance, which is disfavored by mathematicians due to its inelegance in integrating.<br />
<br />
British Historian Paul Johnson declares the turning point in 20th century to have been when fellow Briton Sir [[Arthur Eddington]], an esteemed English astronomer, ventured out on a boat off Africa in 1919 with a local Army unit to observe the bending of starlight around the sun during a total eclipse. Upon his return to England declared that his observations proven the theory of relativity. In fact recent analysis of Eddington's work revealed that he was biased in selecting his data, and that overall his data were inconclusive about the theory of relativity. The prediction was later confirmed by more rigorous experiments, such as those performed by the [[Hubble Space Telescope]] <ref>[http://www.spaceimages.com/gravlen.html Hubble Gravitational Lens Photo]</ref><ref> [http://csep10.phys.utk.edu/astr162/lect/galaxies/lensing.html Gravitational Lensing] </ref><ref>[http://www.iam.ubc.ca/~newbury/lenses/glgallery.html]</ref>. Lorentz has this to say on the discrepancies between the empirical eclipse data and Einstein's predictions.<br />
<br />
::''It indeed seems that the discrepancies may be ascribed to faults in observations, which supposition is supported by the fact that the observations at Prince's Island, which, it is true, did not turn out quite as well as those mentioned above, gave the result, of 1.64, somewhat lower than Einstein's figure.''<ref>Lorentz, H.A. [http://ia331314.us.archive.org/2/items/theeinsteintheor11335gut/11335-h/11335-h.htm The Einstein Theory of Relativity]</ref><br />
<br />
The prediction that light is bent by gravity is predicted both by Newtonian physics and relativity, but relativity predicts a larger deflection.<br />
<br />
Special relativity is the limiting case of general relativity where all gravitational fields are weak. Alternatively, special relativity is the limiting case of general relativity when all reference frames are inertial (non-accelerating and without gravity).<br />
<br />
==Lack of evidence for Relativity==<br />
The Theory of relativity assumes that time is symmetric just as space is, but the biggest early promoter of relativity, Arthur Eddington, coined the term "[[arrow of time]]" admitting how time is ''not'' symmetric but is directional. The passage of time is tied to an increase in disorder, or [[entropy]]. The Theory of relativity cannot explain this, and implicitly denies it, specifically allowing for theoretical time travel (e.g., [[wormholes]]) and different rates of passage of time based on velocity and acceleration.<br />
<br />
Claims that relativity was used to develop the [[Global Positioning System]] ([[GPS]]) are not false. A 1996 article explains badly:<br />
<br />
:"The Operational Control System (OCS) of the Global Positioning System (GPS) does not include the rigorous transformations between coordinate systems that Einstein's general theory of relativity would seem to require - transformations to and from the individual space vehicles (SVs), the Monitor Stations (MSs), and the users on the surface of the rotating earth, and the geocentric Earth Centered Inertial System (ECI) in which the SV orbits are calculated. There is a very good reason for the omission: the effects of relativity, where they are different from the effects predicted by classical mechanics and electromagnetic theory, are too small to matter - less than one centimeter, for users on or near the earth."<ref>http://tycho.usno.navy.mil/ptti/1996/Vol%2028_16.pdf</ref><ref>Some do claim that relativity is "vital" to GPS even though GPS developed independently of theoretical predictions and theoreticians disagree about how the relativistic effects for GPS should be calculated. ''See id. See also'' [http://www.rand.org/pubs/monograph_reports/MR614/MR614.appb.pdf]</ref><br />
<br />
This article, which was published in 1996, goes on to propose relativistic corrections that might be used to design more accurate GPS systems. Clocks on board GPS satellites require adjustments to their clock frequencies if they are to be synchronized with those on the surface of the Earth. <br />
<br />
Tom Van Flandern, an astronomer hired to work on GPS in the late 1990s, concluded that "[t]he GPS programmers don't need relativity." He was quoted as saying that the GPS programmers "have basically blown off Einstein."<ref>http://archive.salon.com/people/feature/2000/07/06/einstein/index.html See also [http://www.metaresearch.org/solar%20system/gps/absolute-gps-1meter-3.ASP], where Van Flandern discusses how relativistic corrections might improve GPS accuracy.</ref> Asynchronization can be easily addressed through communications between the satellites and ground stations, so it is unclear why any theory would be needed for GPS. While Van Flandern believed that relativity is unnecessary for GPS, he also asserted that observations of GPS satellites supported both general and special relativity, writing that "we can assert with confidence that the predictions of relativity are confirmed to high accuracy over time periods of many days," with unrelated factors interfering with longer-term observations. <ref>http://www.metaresearch.org/cosmology/gps-relativity.asp</ref><br />
<br />
Some internet articles claim that GPS timing differences ''confirm'' the Theory of Relativity or its Lorentzian counterpart (which uses a preferred frame of reference). GPS clocks run slower in the weaker gravitation field of the satellites than on ground stations on Earth, with the effects predicted by general relativity far outweighing the effects predicted by special relativity. However, the articles claiming that the slower GPS satellite clocks confirm relativity do not address the effect, if any, of the weaker gravitational force under Newton's theory on the GPS satellite clocks, likely because in Newtonian Mechanics every clock in the universe keeps time at the same rate regardless of velocity, acceleration, or the presence or absence of force.<br />
<br />
Currently, GPS satellites are synchronized to Coordinated Universal Time by radio signals from the ground; therefore, they cannot currently be used to test general relativity.<ref>[http://www.phys.lsu.edu/mog/mog9/node9.html "General Relativity in the Global Positioning System."] Neil Ashby, U. of Colorado</ref><br />
<br />
There are claims that the effects of relativity have been observed with the frequency shift of the signal being sent back to [[Earth]] several times as various spacecraft have dipped into the gravity wells around massive objects such as the [[sun]] (see image at right)<ref>[http://saturn.jpl.nasa.gov/news/press-releases-03/20031002-pr-a.cfm Saturn-Bound Spacecraft Tests Einstein's Theory]</ref> or Saturn<ref>[http://www.newscientist.com/article/mg12517102.600-science-encounter-with-saturn-confirms-relativity-theory.html Encounter with Saturn confirms relativity theory]</ref>. A satellite called [[Gravity Probe B]] was put in orbit about the Earth to examine the effects of frame dragging and geodetic warping of space<ref>[http://www.nasa.gov/mission_pages/gpb/index.html NASA Gravity Probe B mission page]</ref><ref>[http://einstein.stanford.edu/ Gravity Probe B project page]</ref>, but the results were inconclusive. Note, however, that Newtonian mechanics also predicts deflection of light by gravity, and in the initial theory of relativity it predicted the same amount of deflection, but only if we treat light as capable of being accelerated and decelerated like ordinary matter, which is contrary to all measurements and observations to date.<ref>http://www.mathpages.com/rr/s6-03/6-03.htm</ref> Adjustments to the theory of relativity resulted in a prediction of a greater deflection of light than that predicated by Newtonian mechanics, though it is debatable how much deflection Newtonian mechanics should predict. <br />
<br />
None of the NASA spacecraft incorporates predictions of relativity into their own timing mechanisms, as Newtonian mechanics is adequate even for probes sent deep into space so long as they do not undergo accelerations near the speed of light or enter any massive gravity wells.<ref>There is no reported reliance on relativity by any space probe.</ref><br />
<br />
A decade of observation of the [[pulsar]] pair [[PSR 1913 16|PSR B1913+16]] detected a decline in its orbital period, which was attributed to a loss in energy by the system. It is impossible to measure the masses of the pulsars, their accelerations relative to the observers, or other fundamental parameters. Professors Joseph Taylor and Russell Hulse, who discovered the binary pulsar, found that physical values could be assigned to the pulsars to make the observed decline in orbital period consistent with the Theory of General Relativity, and for this they were awarded the 1993 [[Nobel Prize]] for Physics, which is the only award ever given by the Nobel committee for the Theory of Relativity.<ref>http://nobelprize.org/nobel_prizes/physics/laureates/1993/press.html</ref> In 2004, Professor Taylor utilized a correction to the derivative of the orbital period to fit subsequent data better to the theory. At most, assumptions can be made and altered to fit the data to the theory, rather than the data confirming the theory.<br />
<br />
The [[perihelion]] of Mercury's [[orbit]] [[precession|precesses]] at a measurable rate, but even after accounting for gravitational perturbations caused all other planets in the [[solar system]], Newton's theory (assuming a precise inverse-square relationship for distance) predicts a rate of precession that differs from the measured rate by approximately 43 [[arcsecond]]s per century. General relativity was developed in part to provide an estimate for this rate of precession that better matches observations.<ref>http://physics.ucr.edu/~wudka/Physics7/Notes_www/node98.html#SECTION032121000000000000000</ref> <ref> http://www.alberteinstein.info/gallery/pdf/CP6Doc30_English_pp146-200.pdf</ref> <ref> http://farside.ph.utexas.edu/teaching/336k/lectures/node117.html</ref> Newton's theory can also explain this perihelion by making tiny adjustments to parameters in the gravitational equation.<br />
<br />
General relativity predicts twice as much bending in light as it passes near massive objects than Newton's theory might predict.<ref>http://www.mathpages.com/rr/s6-03/6-03.htm</ref> This phenomenon is known as [[gravitational lens|gravitational lensing]]. A large number of instances of gravitational lensing have been observed, and it is now a standard astronomical tool.<ref> http://imagine.gsfc.nasa.gov/docs/features/news/grav_lens.html</ref> <ref> http://astro.berkeley.edu/~jcohn/lens.html</ref> <ref> http://www.iam.ubc.ca/~newbury/lenses/glgallery.html</ref> Note, however, that the extent of bending of light predicted by Newton's theory is open to debate, and depends on assumptions about the nature of light for gravitational purposes.<ref>http://cosmictimes.gsfc.nasa.gov/1919/guide/gravity_bends_starlight.html</ref><br />
<br />
In 1972, scientists flew extremely accurate clocks ("atomic clocks") around the world in both directions on commercial airlines, and claimed to observe relativistic time dilation; the eastbound clock gained 273 ns and the westbound clock lost 59 ns, matching the predictions of general relativity to within experimental accuracy.<ref>[http://www.answers.com/topic/hafele-keating-experiment Hafele-Keating Experiment]</ref> However, the inventor of the atomic clock, Louis Essen, declared that the experiment was inaccurate.<ref>Louis Essen, Electron. Wireless World 94 (1988) 238.</ref> Dr A. G. Kelly examined the raw data from the experiment and declared it inconclusive.<ref>A. G. Kelly,Reliability of Relativistic Effect Tests on Airborne Clocks, Monograph No.3 Feb.1996, The Institution of Engineers of Ireland, ISBN 1-898012-22-9</ref> The Nobel Committee chose not to honor this experiment for the significance that was claimed.<br />
<br />
Despite [[censorship]] of dissent about relativity, evidence contrary to the theory is discussed outside of [[liberal]] universities.<ref>http://scitizen.com/screens/blogPage/viewBlog/sw_viewBlog.php?idTheme=8&idContribution=922</ref><br />
<br />
==Experiments that Fail to Prove Relativity==<br />
<br />
The different effects predicted by special relativity, compared to classical formulations, are extremely tiny. Most relativistic effects are negligible at the speeds of ordinary phenomena observed by humans. The effects only become significant when the speeds involved are a significant fraction of the speed of light, which is <math>3 \times 10^8</math> meters per second&mdash;such speeds are called ''relativistic''. (However, it's worth noting that ordinary magnetism can be considered an effect of relativity, dictated by the need for electrostatic theory to be correct under relativity. The speed of light in fact appears in the formulas ([[Maxwell's Equations]]) governing electricity and magnetism, though these equations were developed long before relativity was proposed.)<br />
<br />
Because the effects of relativity are so tiny, scientists have been devising sophisticated and sensitive tests ever since the theory was formulated in 1905.<br />
<br />
*At the end of Einstein's original 1905 paper [http://www.fourmilab.ch/etexts/einstein/E_mc2/www/ "Does the Inertia of a Body Depend its Energy Content?"], he speculates on the possibility that the equation <math>E = m c^2</math>, which would normally be very hard to verify, could be verified with the extremely high energies of the newly-discovered phenomenon of radioactivity.<ref>This equation is not related to [[quantum mechanics]].</ref> In the 1910's, with the invention of the mass spectrometer, it became possible to measure masses of nuclei accurately. This led to the clearing up of the mystery of atomic masses not being exact integers,and strongly suggested the existence of a "mass defect" (or "packing fraction") consistent with the mass-energy equivalence. In the 1930's, experiments with known nuclear reactions showed a very accurate correlation between the masses of the nuclei involved and the energy released.<br />
<br />
*Another prediction of special relativity was time dilation in rapidly moving objects. This effect was most famously verified in the anomalously slow decay of relativistic cosmic muons<ref>Some have suggested that other explanations are possible for this effect. We are trying to track this down.</ref>. Time dilation has since been verified many times, and is routinely taken into account in all high-energy nuclear physics experiments, as in Hadron collision experiments<ref>Experiments specifically designed to check dilation are rarely conducted any more.</ref>.<br />
<br />
Predictions of general relativity turned out to be more obscure and difficult to test. The two most famous predictions were the bending of light in a gravitational field and the precession of the perihelia of orbiting planets.<br />
<br />
*The first of these was famously tested during a total eclipse in 1919. That test was somewhat muddled by an incorrect initial calculation, by several people including Einstein himself, of what the effect would be, and some "cherry picking" of the data to be used <ref>''Einstein's Luck'', John Waller, Oxford University Press, ISBN 0-19-860719-9</ref>. The data selection could be considered "manipulation" or "fudging", by a person (Arthur Eddington) who had a personal stake in the outcome. His analysis techniques would not pass muster today.<br />
<br />
:It should be noted that pre-relativistic (Newtonian) physics may also predict a bending, of half the observed value, depending on whether one uses the 17<sup>th</sup> century "corpuscular" formulation or the 19<sup>th</sup> century "wave" formulation.<br />
<br />
:Nevertheless, it has been verified with ever-increasing precision in subsequent eclipses, and in the observations of quasar 3C273.<br />
<br />
*The second "classical" test of general relativity was the advance of the perihelion of the orbit of Mercury. There are many complex effects contributing to this, including gravitational perturbations from other planets and the effect of the oblateness of the Sun. These are hard to calculate accurately, but, by 1900 it was known quite accurately that there was an "anomalous" precession, that is, a precession beyond all other known effects, of 43 arc seconds per century. This is a very tiny effect, but astronomical measurements were sufficiently accurate by that time to show it clearly.<br />
<br />
:This created quite a problem&mdash;physicists by then were accustomed to having their theories check out very accurately. One proposal that was made, by Simon Newcomb and Asaph Hall, was that the exponent of the radius in the gravitational formula wasn't exactly 2. He showed that, by choosing an exponent of <math>2+\delta</math>, the precession, as a fraction of a full orbit per planet's year, is <math>\delta/2</math>. By setting <math>\delta</math> to .000000157, that is, an exponent of 2.000000157, Newcomb was able to get a precession of .000000078 revolutions per Mercury year, or 43 arcseconds per Earth year. The primary resistance to this approach came from mathematicians unable to do the integration without an exponent of precisely 2, and they insisted, incorrectly, that was impossible for the exponent to be slightly different from 2. Due to this desire for mathematical elegance rather than objective observation-based science, Newcomb's approach was not pursued. Furthermore as can be seen from the table below the measured values of the anomalous precessions of other planets agree well with the predictions of general relativity but poorly with those predicted by Newcomb and Hall.<br />
<br />
:While Newcomb's theory, and general relativity, don't lead to closed-form solutions, both theories can be solved numerically to as much precision as one desires.<br />
<br />
:Increasingly precise measurements of the precession demonstrate that it conflicts with General Relativity, despite claims of relativists for decades that it predicted the precession accurately in the amount of <math>3{}v^2/c^2</math> revolutions per planet's "year", where <math>v</math> is the planet's average orbital speed.<ref>That is a simple approximation, designed to relate the precession to the planet's speed relative to the speed of light. A more accurate approximation is <math>\frac{3GM}{c^2 a(1-e^2)}</math>, where a is the semi-major axis and e is the eccentricity.</ref> The conflict is greater than the margin of error, and many relativists avoid the discrepancy rather than address it.<br />
<br />
:The following table show some approximate parameters for the planets. Note that Mercury has the smallest orbit, the fastest speed, and the highest gravitational pull. Precession of planets other than Mercury is extremely hard to measure, but measurements of the actual anomalous precessions are in good agreement .<ref>http://www.mathpages.com/rr/s6-02/6-02.htm</ref><br />
<br />
{| class="wikitable"<br />
|-<br />
!Planet<br />
!Period, seconds x 10<sup>6</sup><br />
!Semimajor axis, meters x 10<sup>9</sup><br />
!Speed, meters/second x 10<sup>3</sup><br />
!Gravitational force, Newtons per kilogram<br />
!Anomalous precession, arcseconds per (Earth) century, pure Newtonian mechanics<br />
!Anomalous precession, Newtonian with exponent of 2.000000157<br />
!Anomalous precession, general relativity<br />
!Measured anomalous precession (estimated uncertainty)<ref>http://www.mathpages.com/rr/s6-02/6-02.htm</ref><br />
|-<br />
|Mercury<br />
|7.57<br />
|58.9<br />
|48<br />
|.039<br />
|0<br />
|43<br />
|43<br />
|43.5(5)<br />
|-<br />
|Venus<br />
|19.6<br />
|108<br />
|35<br />
|.011<br />
|0<br />
|16.6<br />
|9<br />
|8(5)<br />
|-<br />
|Earth<br />
|31.6<br />
|150<br />
|30<br />
|.006<br />
|0<br />
|10.3<br />
|4<br />
|5(1)<br />
|-<br />
|Mars<br />
|59.3<br />
|227.9<br />
|24<br />
|.0025<br />
|0<br />
|5.5<br />
|1.4<br />
|<br />
|-<br />
|Jupiter<br />
|374<br />
|778.4<br />
|13<br />
|.0002<br />
|0<br />
|0.87<br />
|0.07<br />
|<br />
|-<br />
|Saturn<br />
|929<br />
|1426<br />
|9.7<br />
|.00006<br />
|0<br />
|0.35<br />
|0.014<br />
|<br />
|-<br />
|Uranus<br />
|2651<br />
|2870<br />
|6.8<br />
|.000016<br />
|0<br />
|0.12<br />
|0.002<br />
|<br />
|-<br />
|Neptune<br />
|5200<br />
|4498<br />
|5.5<br />
|.000007<br />
|0<br />
|0.063<br />
|0.0008<br />
|<br />
|}<br />
<br />
[[Image:Cassini-science-289.jpg|right|thumb|The Shapiro effect: A spacecraft signal dipping into a gravity well around the [[Sun]] is delayed slightly.]]<br />
As the 20<sup>th</sup> century progressed, more tests of general relativity were proposed.<br />
<br />
*One was the ''Shapiro effect'', involving time delay in radio signals passing through the gravity well of the Sun or a planet. Various spacecraft have confirmed this.<br />
<br />
*Another is ''gravitational time dilation''. This is an effect separate from the time dilation of special relativity. It was tested by the Pound-Rebka experiment in 1959.<br />
<br />
*Later in the 20<sup>th</sup> century, even more subtle phenomena were tested. One was the phenomenon of ''gravitational radiation'', or "gravity waves". These waves are incredibly difficult to observe, and have never been observed. But extremely dense binary pulsars radiate gravitational waves with sufficient energy loss that, even though we can't detect the waves from Earth, we can see the effect of the energy loss from the radiation. The extreme precision of the timing of pulses from pulsars makes it possible to observe their energy loss with great accuracy. Observations by Hulse and Taylor of the pulsar pair known as B1913+16, if assumptions are made, could make the energy loss appear consistent with the predicted radiation. Those observations have not been followed up with more recent, precise data, raising questions about whether the pulsar data is consistent with the theory today.<br />
<br />
*Two other effects, ''geodetic precession'' (also known as "de Sitter precession"), and ''frame dragging'' (also known as the "Lense-Thirring effect") were tested by the "Gravity Probe B" satellite early in the 21<sup>st</sup> century<ref>http://prl.aps.org/accepted/L/ea070Y8dQ491d22a28828c95f660a57ac82e7d8c0</ref><ref>http://www.digitaljournal.com/article/306430</ref><ref>http://www.nap.edu/html/gpb/summary.html</ref><ref>http://www.sciencenews.org/view/generic/id/73870/title/Gravity_Probe_B_finally_pays_off_</ref><ref>http://www.nasa.gov/mission_pages/gpb/</ref><ref>http://einstein.stanford.edu/</ref><ref>http://spectrum.ieee.org/aerospace/space-flight/the-gravity-probe-b-bailout</ref><ref>http://www.engadget.com/2011/05/06/nasa-concludes-gravity-probe-b-space-time-experiment-proves-e/</ref>. The precision required to observe this was phenomenal. The results were announced on May 4, 2011.<br />
<br />
{{clear}}<!-- make the Shapiro picture not obliterate the next section heading --><br />
<br />
==Predicted consequences of the Theories==<br />
===Time dilation===<br />
<!-- NOTE [[Time dilation]] redirects to this section, so the section name should not be changed without amending that redirect. --><br />
[[Image:Light cone.png|right|thumb|Light-cone diagram]]<br />
One important consequence of SR's postulates is that an observer in one reference frame will observe a clock in another frame to be "ticking" more slowly than in the observer's own frame. This can be proven mathematically using basic geometry, if the postulates are physically true without exception.<br />
<br />
The length of an event <math>t</math>, as seen by a (relative) stationary observer observing an event is given by:<br />
<br />
<math> t = \frac{t_{0}} {\sqrt{1 - \frac{v^{2}}{c^{2}}}}</math> <br />
<br />
Where <br />
:<math>t_0</math> is the "proper time" or the length of the event in the observed frame of reference.<br />
:<math>v</math> is the relative velocity between the reference frames.<br />
:<math>c</math> is the speed of light (3x10<sup>8</sup> ms<sup>-1</sup>).<br />
<br />
Evidence for time dilation was discovered by studying [[muon decay]]. [[Muons]] are [[subatomic]] [[particles]] with a very short [[halflife]] (1.53 microseconds at rest) and a very fast speed (0.994c). By putting muon detectors at the top (D<sub>1</sub>) and bottom (D<sub>2</sub>) of a mountain with a separation of 1900m, scientists could measure accurately the proportion of muons reaching the second detector in comparison to the first. The proportion found was different to the proportion that was calculated without taking into account relativistic effects.<br />
<br />
Using the equation for [[exponential decay]], they could use this proportion to calculate the time taken for the muons to decay, relative to the muon. Then, using the time dilation equation they could then work out the dilated time. The dilated time showed a good correlation with the time it took the muons to reach the second sensor, thereby supporting the existence of time dilation.<br />
<br />
The time taken for a muon to travel from D<sub>1</sub> to D<sub>2</sub> as measured by a stationary observer is:<br />
<br />
<math> t = \frac{s}{v} = \frac{1900}{0.994\times(3\times10^{8})} = 6.37\mu\textrm{s} </math><br />
<br />
The fraction of muons arriving at D<sub>2</sub> in comparison to D<sub>1</sub> was 0.732. (Given by <math> \frac{N}{N_0} = 0.732 </math>)<br />
<br />
Since (from the equation for exponential decay) <math> \frac{N}{N_{0}} = e^{-\lambda t_{0}} </math> then<br />
<br />
<math> t_{0} = \frac {ln(0.732)}{ln (0.2)} \times 1.53\times 10^{-6} = 0.689\mu\textrm{s}</math><br />
<br />
This gives the time for the proportion of decay to occur for an observer who is stationary, relative to the muon.<br />
<br />
Putting this into the time dilation equation gives:<br />
<br />
<math> t = \frac{t_{0}}{\sqrt{1 - \frac{v^{2}}{c^{2}}}} = \frac{0.689 \times{10^{-6}}}{\sqrt{1 - \frac{0.994^{2}}{1^{2}}}} = 6.3\times 10^{-6}\textrm{s}</math><br />
<br />
This is in good agreement with the value calculated above, thereby providing evidence to support time dilation.<br />
<br />
====Time Dilation and Creation Science====<br />
<br />
{{main|Starlight problem#Humphreys.27_model}}<br />
<br />
Creation scientists such as physicists Dr. [[Russell Humphreys]] and Dr. [[John Hartnett]] have used relativistic time dilation to explain how the earth can be only 6,000 years old even though cosmological data (background radiation, supernovae, etc.) set a much older age for the universe.<br />
<br />
===Length contraction===<br />
When two inertial reference frames move past each other in a straight line with constant relative velocity, an observer in one reference frame would observe a metre rule in the other frame to be shorter.<br />
<br />
The length, <math>l</math>, of an object as seen by a (relative) stationary observer is given by:<br />
<br />
<math> l = l_{0} \sqrt{1- \frac{v^{2}}{c^{2}}}</math><br />
<br />
Where <br />
:<math>l_0</math> is the "proper length" or the length of the object in the observed frame of reference.<br />
:<math>v</math> is the relative velocity between the reference frames.<br />
:<math>c</math> is the speed of light (3x10<sup>8</sup> ms<sup>-1</sup>).<br />
<br />
===Mass increase===<br />
<br />
For decades the theory of relativity taught that as a body moves with increasing velocity its [[mass]] also increases.<ref>For example, this was taught as recently as in the 1991 edition of the Encyclopedia Britannica.</ref><br />
<br />
Under this view, the mass, <math>m</math>, of an object as detected by a (relative) stationary observer is given by:<br />
<br />
:<math> m = \frac{m_{0}} {\sqrt{1 - \frac{v^{2}}{c^{2}}}}</math><br />
<br />
Where <br />
:<math>m_0</math> is the "rest mass" or the mass of the object when it is at rest.<br />
:<math>v</math> is the relative velocity of the object.<br />
:<math>c</math> is the speed of light (3x10<sup>8</sup> ms<sup>-1</sup>).<br />
<br />
Since speed is relative, it follows that two observers in different inertial reference frames may disagree on the mass and kinetic energy of a body. Since all inertial reference frames are treated on an equal footing, it follows that mass and energy are interchangeable.<br />
<br />
In recent years most physicists have shifted away from Einstein's original reliance on relativistic mass and his suggestion that mass increases{{Citation needed|date=January 2012}}. Instead, most physicists today teach that <br />
<br />
:<math>F=\frac{d}{d\tau} p</math> <br />
<br />
where <math>p</math> is the momentum defined by <math>\gamma m v</math>, <math>\gamma</math> is the standard Lorentz factor, and <math>\tau</math> is the proper time. Force F defined this way is a vector and thus can handle the directional aspect of the relativistic effects better than the concept of relativistic mass can.<br />
<br />
<br />
The abandonment by physicists of the concept of relativistic mass, however, has the consequence of undermining the traditional claim under relativity that<br />
<br />
:<math>m - m_0 = \frac{E}{c^2}</math> <br />
<br />
also popularly known as<br />
<br />
:<math>E = m c^2</math><br />
<br />
Now a concept of the 4-momentum <math>p</math> of a particle is taught, such that the square of the magnitude of <math>p</math> satisfies:<br />
<br />
<math>||p||^2 = -p_x^2-p_y^2-p_z^2+E^2 = m_0^2c^4</math> <br />
<br />
in any inertial reference frame. The magnitude of the 4-momentum, in any inertial frame, equals the rest mass <math>m_0</math> of the particle (in units where <math>c=1</math>).<br />
<br />
== Paradoxes ==<br />
<br />
The predictions of the theory of relativity throw up a number of apparent paradoxes and anomalies relating to the effects of time dilatation and length contraction. Whilst these paradoxes are consistent with the theory, they are contrary to everyday human experience and therefore can seem like impossibilities.<br />
<br />
=== The Twin Paradox ===<br />
<br />
The twin paradox is usually stated as a thought experiment involving two twins, one of whom is sent on a long journey in a spacecraft travelling at close to the speed of light, whilst the other remains on Earth. Time dilatation means that the travelling twin, on his return to Earth, is younger that the twin who has remained at home. However because neither twin is in a special position - each being in an inertial frame of reference - the reverse must also be true, and so the twin remaining on Earth must be younger. Hence each twin is younger than the other - a paradox.<br />
<br />
The problem can be resolved in two ways. One is to examine the effects of General Relativity: to come back to Earth, the travelling twin must undergo acceleration in order to reverse his course, causing temporal effects which make him permanently the younger. Alternatively, it can be explained entirely using Special Relativity and noting that the twins are not in symmetrical situations: the one on earth has remained in a single inertial frame of reference, whilst the travelling twin has travelled in two<ref>http://mentock.home.mindspring.com/twins.htm</ref>.<br />
<br />
=== The Ehrenfest Paradox ===<br />
<br />
The Ehrenfest Paradox considers a rigid wheel or disc rotating a bout its axis at high speed (somewhat like a bicycle wheel spinning freely on its axle). The rim of the wheel travels at close to the speed of light and therefore undergoes length contraction, whereas the radius (the spokes, for the bicycle wheel) does not. Hence the circumference is no longer equal to 2<big><math>\pi</math></big>r, which is paradoxical.<br />
<br />
The apparent paradox was finally resolved in 1975 by the Norwegian scientist [[Øyvind Grøn]]<ref>http://www.physicsforums.com/showthread.php?t=224955</ref>.<br />
<br />
== Variable Speed of Light ==<br />
<br />
The Theory of Relativity implies that physical constants like c, the speed of light in a vacuum, have remained constant. But at least one study suggests that physical constants, and possibly even the speed of light, have changed as the universe has aged.<ref>James Glanz and Dennis Overbye, "Cosmic Laws Like Speed of Light Might Be Changing, a Study Finds," August 15, 2001.[http://www.nytimes.com/2001/08/15/science/15PHYS.html?ex=1185076800&en=d6467b6e3e346796&ei=5070]</ref><br />
<br />
"For the first time, scientists have experimentally demonstrated that sound pulses can travel at velocities faster than the speed of light, c. William Robertson's team from Middle Tennessee State University also showed that the group velocity of sound waves can become infinite, and even negative. ... Although such results may at first appear to violate special relativity (Einstein's law that no material object can exceed the speed of light), the actual significance of these experiments is a little different. These types of superluminal phenomena, Robertson et al. explain, violate neither causality nor special relativity, nor do they enable information to travel faster than c. In fact, theoretical work had predicted that the superluminal speed of the group velocity of sound waves should exist. 'The key to understanding this seeming paradox is that no wave energy exceeded the speed of light,' said Robertson."<ref>http://www.physorg.com/news88249076.html</ref><br />
<br />
"A team of researchers from the Ecole Polytechnique Fédérale de Lausanne (EPFL) has successfully demonstrated, for the first time, that it is possible to control the speed of light – both slowing it down and speeding it up – in an optical fiber, using off-the-shelf instrumentation in normal environmental conditions. Their results, to be published in the August 22 issue of Applied Physics Letters, could have implications that range from optical [[computing]] to the fiber-optic telecommunications industry."<ref>http://www.scienceblog.com/light.html</ref> Both slowing down and speeding up of light within a substance other than a vacuum is made possible, because the light travels through the material, and that material affects the speed of light, i.e. a photon hits an electron, which then exits and emits a slightly lower energy photon out in the direction that the original photon was traveling, thus maintaining conservation of momentum. No matter how transparent an object may appear, it radically impacts the speed of the light traveling through it, as demonstrated by the refractive production of a rainbow by a crystal, which Newton himself discovered.<br />
<br />
This apparent change in speed can be explained, however, by noting that the constant c refers to the speed of light in a vacuum, ie, when it is unimpeded. The speed of light when traveling through physical media is, in fact, variable.<br />
<br />
"A pair of German physicists claim to have broken the speed of light - an achievement that would undermine our entire understanding of space and time. ... Dr Nimtz told New Scientist magazine: 'For the time being, this is the only violation of special relativity that I know of.'"<ref>http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2007/08/16/scispeed116.xml</ref><br />
<br />
==Pending research==<br />
<br />
Today some physicists are working on hypothesizing how general relativity might have related to the other three forces of nature during the first fraction of a second of the [[Big Bang]]. Two of the more commonly studied attempts are [[string theory]] and [[loop quantum gravity]], but they have failed to produce any evidence that science mandates a science must have, and both typically take large amounts of work to even conform to what scientists believe. Critics increasingly point out that string theory and loop quantum gravity are largely untestable and unfalsifiable, and thus potentially unscientific under the principles of science advanced by [[Karl Popper]].<ref>See, for example, ''Not Even Wrong'', by Peter Woit</ref><br />
<br />
Relativity continues to be tested and some physics professors remain skeptical of the theory, such as University of Maryland physics professor Carroll Alley, who served as the principle physicist on the Apollo lunar project.<ref>http://science.nasa.gov/headlines/y2004/21jul_llr.htm</ref><br />
<br />
== Political aspects of relativity ==<br />
<br />
Some [[liberal]] politicians have extrapolated the theory of relativity to metaphorically justify their own political agendas. For example, [[Democratic]] [[President of the United States of America|President]] [[Barack Obama]] helped publish an article by liberal law professor [[Laurence Tribe]] to apply the relativistic concept of "curvature of space" to promote a broad legal right to [[abortion]].<ref>Tribe, acknowledging help by Obama, argued that the [[Constitution]] should be interpreted to establish a right to federally funded [[abortion]] and that, more generally, ''[[Roe v. Wade]]'' does not go far enough. They insisted that a relativistic "curvature of space" could achieve this result by expanding application of the [[Constitution]] based on its impact on personal choice. "The ''[[Roe v. Wade]]'' opinion ignored the way in which laws regulating pregnant women may shape the entire pattern of relationships among men, women, and children. It conceptualized abortion not in terms of the intensely public question of the subordination of women to men through the exploitation of pregnancy, but in terms of the purportedly private question of how women might make intimately personal decisions about their bodies and their lives. That vision described a part of the truth, but only what might be called the Newtonian part. ... [A] change in the surrounding legal setting can constitute state action that most threatens the sphere of personal choice. And it is a 'curved space' perspective on how law operates that leads one to focus less on the visible lines of legal force and more on how those lines are bent and directed by the law's geometry." Laurence H. Tribe, The Curvature of Constitutional Space: What Lawyers Can Learn from Modern Physics, 103 Harv. L. Rev. 1, 16-17 (1989).</ref> As of June 2008, over 170 law review articles have cited this [[liberal]] application of the theory of relativity to legal arguments.<ref>Search conducted by [[User:Aschlafly]] in the LEXIS database "US Law Reviews and Journals, Combined," conducted June 1, 2008.</ref> Applications of the theory of relativity to change morality have also been common.<ref>"Mistakenly, in the minds of many, the theory of relativity became relativism."[http://www.worldnetdaily.com/news/article.asp?ARTICLE_ID=38081]</ref> Moreover, there is an unmistakable effort to censor or ostracize criticism of relativity.<ref>Although the [[Examples of Bias in Wikipedia|liberally biased Wikipedia]] contains lengthy criticisms of the subjects of many entries, and even though publications like ''The Economist'' recognize the lack of scientific satisfaction in the theory (see, e.g., "Weighing the Universe," The Economist (Jan. 25, 2007)), Wikipedia's entry on [http://en.wikipedia.org/wiki/Theory_of_Relativity Theory of Relativity] omits one word of criticism.</ref> <br />
<br />
Physicist [[Robert Dicke]] of Princeton University was a prominent critic<ref>http://www.time.com/time/magazine/article/0,9171,943324,00.html</ref> of general relativity, and Dicke's alternative "has enjoyed a renaissance in connection with theories of higher dimensional space-time."<ref>"Initially a popular alternative to General Relativity, the Brans-Dicke theory lost favor as it became clear that omega must be very large-an artificial requirement in some views. Nevertheless, the theory has remained a paradigm for the introduction of scalar fields into gravitational theory, and as such has enjoyed a renaissance in connection with theories of higher dimensional space-time."[http://nedwww.ipac.caltech.edu/level5/Glossary/Essay_bekenstein.html] </ref> Despite being one of the most accomplished physicists in the 20th century, Dicke was repeatedly passed over for a [[Nobel Prize]], and in at least one case Dicke was insulted by the award being granted to others for contributions more properly credited to Dicke.<br />
<br />
There has been little recognition by the Nobel Prize committee of either theory of relativity, and particularly scant recognition of the Theory of General Relativity. A dubious 1993 Nobel prize in physics was awarded Hulse and Taylor for supposedly finding the first evidence of gravitational waves in the orbital decay of the binary pulsar PSR1913+16 <ref>Weisberg, Joel M.; Taylor, Joseph H. (2003), "The Relativistic Binary Pulsar B1913+16"", in Bailes, M.; Nice, D. J.; Thorsett, S. E., Proceedings of "Radio Pulsars," Chania, Crete, August, 2002, ASP Conference Series</ref>. A close reading of the paper reveals that that is based heavily on assumptions in trying to retrofit the data to the theory.<br />
<br />
===Government Support for Relativistic research===<br />
The Theory of Relativity enjoys a disproportionate share of [[federal funding]] of physics research today.<ref>The Democratic Congress insisted on the $250 million LIGO project despite substantial criticism by scientists that it was wasting scarce research dollars. John Travis, "LIGO: a $ 250 million gamble; Laser Interferometer Gravitational-Wave Observatory; includes related article," ''Science'' p. 612 (Apr. 30, 1993). "Adding to the acrimony is LIGO's $ 250 million price tag, which some hold responsible for NSF's recent funding woes." ''Id.''</ref> In at least one case that research has been unsuccessful. The $365 million dollar [[LIGO]] project has failed to detect the gravity waves predicted by relativity.<ref>http://www.npr.org/programs/atc/features/2002/sept/gravitywaves/index.html</ref><br />
<br />
{{Relativity}}<br />
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== References ==<br />
{{reflist|2}}<br />
<br />
[[Category:Physics]]<br />
[[Category:Science]]<br />
<br />
==External Links ==<br />
*[http://ia331314.us.archive.org/2/items/theeinsteintheor11335gut/11335-h/11335-h.htm The Einstein Theory of Relativity, by H.A. Lorentz.]<br />
*[http://www.relativitycalculator.com Relativity Calculator - Learn Special Relativity Mathematics ] The mathematics of special relativity presented in as simple and comprehensive manner possible within philosophical and historical contexts.</div>Borbon