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Line 1: − − == Works == − Einstein contributed to the theory of a [[Special Relativity]] and the theory of [[General Relativity]]. He also contributed to the study of [[photoelectric effect]], Brownian Motion and Bose-Einstein Statistics. He was critical of quantum mechanics and has proposed the EPR-Paradox in attempt to point out spooky aspects of the theory. The last fifteen years of his life were spent in unsuccessfully searching for a [[Unified Field Theory]]. − Einstein's best-known scientific work is his 1905 papers on [[Special Relativity]]. Einstein did not cite any references and it was widely and falsely assumed that his work was original. The theory of relativity had already been published by [[Hendrik Lorentz]] and [[Henri Poincaré]]. Einstein's contribution was to give a description of the Lorentz-Poincare theory without reference to the luminiferous aether, and to clarify some of the physical consequences of the theory. He used the term "stationary system" instead of the term aether. − − Einstein then wrote a series of papers applying relativity to gravity using the mathematics of Riemannian Geometry, contributing to [[General Relativity]]. Much of the actual mathematics of general relativity was worked out by Marcel Grossman, [[David Hilbert]], and others. Einstein's main contribution was to give an alternate derivation of the field equations, and to apply them to explain an [[anomaly]] in the advance of the perihelion in Mercury's orbit. − [[Arthur Eddington]] popularized General Relativity by publishing an explanation of it and by attempting to prove the theory experimentally in a dramatic test. Eddington embarked on a highly publicized trip into the Atlantic Ocean off Africa in order to observe the bending of [[star]]light passing nearby the [[Sun]] during the total [[solar eclipse]] of May 29, 1919. Eddington returned with a declaration that he had proven Einstein's theory of [[General Relativity]], making Einstein extremely famous<ref>Lightman, Alan (September 9, 1997). [http://www.pbs.org/wgbh/nova/einstein/relativity/ "Relativity and the cosmos"]. PBS.org/WGBH/Nova. Retrieved on January 24, 2015. "On November 8, 1919, for example, the ''London Times'' had an article headlined: 'The Revolution In Science/Einstein Versus Newton.' Two days later, ''The New York Times''' headlines read: 'Lights All Askew In The Heavens/Men Of Science More Or Less Agog Over Results Of Eclipse Observations/Einstein Theory Triumphs.'"</ref>, when in fact he had selectively used data to attain this result. No Nobel Prize was given for relativity. − − In April 2004, NASA launched the satellite Gravity Probe B to test general relativity. The main purpose was to test relativistic frame dragging, but the results have been inconclusive. − − Einstein compared the effects of large objects on space and time to the way that a large ball placed on a sheet of rubber stretches the material and causes it to sag, and drew the analogy with the way stars and planets warp space-time. A smaller ball rolling along the sagging fabric will be drawn towards the larger ball, in the same way that the Earth is drawn towards the sun, but will not fall into it as long as it continues to move at sufficient speed. This was a change in thinking from the Newtonian cosmos, in which gravity was viewed purely as an attractive force between bodies. − − Einstein's statistical explanation of Brownian motion (the random movement of microscopic particles mixed in with pollen) is sometimes credited with helping to confirm the atomic theory at a time when some scientists argued against it.<ref>Cassidy, David (2004). [http://www.aip.org/history/einstein/essay-brownian.htm "Einstein on Brownian motion"]. [http://www.aip.org/history/einstein/great1.htm American Institute of Physics/AIP Center for History of Physics/Albert Einstein-Image and Impact/The Great Works I]. Retrieved on January 24, 2014.]</ref> Most scientists had accepted atomic theory a century earlier. − − Einstein also published a heuristic explanation of the photoelectric effect in which light has particle like properties as well as wave like properties. According to [[Maxwell's Equations]], light is a wave so one might expect that increasing the intensity of light should increase the number of electrons emitted from metal. The German physicist Lénard did an experiment proving that this was not true. Einstein argued that the experiment was consistent with [[Max Planck]]'s hypothesis that light is quantized and different particles of light or photons have different frequencies. Therefore, increasing the intensity of low frequency photons has no effect, while using a higher (blue or ultra violet) frequency of light does cause more electrons to be emitted. The formula Einstein used to explain this was Planck's formula ''e'' = ''hf'', where ''h'' is Planck's constant and ''f'' is the frequency.<ref>Davis, Warren, PhD. (2008 or before). [http://www.physlink.com/Education/AskExperts/ae24.cfm?CFID=8792067&CFTOKEN=36662276 "What is the photoelectric effect?"] PhysLink.com. Retrieved on January 24, 2015.</ref> − − Although Einstein won a Nobel Prize for explaining the photoelectric effect, Lénard was critical of his accomplishments.<ref>Evans, Richard J. (2005). ''The Third Reich in Power'' (London: Penguin Books), pp. 306-309.</ref> Planck and Lénard had already received Nobel Prizes for related work explaining the photoelectric effect. − − Einstein also recognized the value in work done by the physicist Satyendra Nath Bose when others did not, and helped Bose publish what is now referred to as Bose-Einstein statistics. A simplified explanation is that the statistics for [[boson]]s (including light) are different from the statistics for fermions which make up solid matter in that there is no way to tag or differentiate one boson from another for statistical comparisons. − − ===E=mc<sup>2</sup>=== − Einstein’s famous formula ''E=mc''<sup>2</sup> says that mass and energy can turn into each other. It was first published by Henri Poincaré. Einstein published an alternate derivation that was corrected and improved by Max Planck. ''E'' stands for [[energy]], ''m'' is [[mass]], and ''c'' is the [[speed of light]]. So, if you increase the energy of a substance, for example by heating it, it gains a minute amount of mass. It was later realized that if you split an atom apart, as in a nuclear explosion, it loses a tiny amount of mass that is released in the form of [[energy]]. − − The connection ''E=mc''<sup>2</sup> to nuclear energy is not as direct as pop culture sometimes represents. Einstein did not discover the huge energy available from nuclear reactions. Early workers in radioactivity, such as [[Ernest Rutherford]], understood clearly that the natural radioactive decay of radium released quantities of energy that could not be explained by chemistry, and were much larger than those of chemical reactions. Neither did Einstein originate the key idea that made nuclear energy a possible weapon or a practical energy source. That was Leo Szilard, who acknowledged having been inspired by a 1914 [[H. G. Wells]] novel. Szilard discovered or invented the chain reaction (and patented it). However, other people recognized the relation between Einstein's interpretation of the ''E=mc''<sup>2</sup> formula and chain reactions. Einstein explained that matter releasing energy is also losing mass. − − Energy binds together the parts of an [[atom]], including the [[nucleus]]. The nucleus of an atom is tiny, but very little mass could release a huge amount of energy. When one nucleus splits apart, it splits other nuclei around it. This is called a [[chain reaction]]. − − ===Cosmological Constant=== − Einstein revised his work on [[General Relativity]] to include a 'fudge-factor' which he termed the [[Cosmological Constant]]. He was trying to account for the apparent steady-state nature of the universe. − − [[Edwin Hubble]], in whose name [[NASA]]'s famous [[Hubble Space Telescope]] is named, later convinced him otherwise. At one point he had Einstein actually making direct observations alongside him, and Hubble's findings showed conclusively that the [[universe]] was indeed expanding, as predicted by certain solutions of GR's field equations in the absence of a cosmological constant. Einstein recanted his original [[philosophy]], and accepted as true the notion of a changing universe having a definite [[begin]]ning. − − He later said of his Cosmological Constant, "It was the biggest blunder of my life." − − An interesting end-note on this term: Principle investigators from [[Princeton University]] first published findings in 1998 apparently revealing an accelerating expansion for the universe<ref>[http://map.gsfc.nasa.gov/m_mm.html "WMAP produces new results"] (2013). NASA/Goddard Space Flight Center/Wilkinson Microwave Anisotropy Probe website. Retrieved on January 25, 2015.</ref>. Because this initially seemed like it might be a sort of 'anti-gravity' effect (similar in concept to Einstein's original notion), it briefly became quite popular for scientists to dub the phenomenon the 'Cosmological Constant' as well. For more information, see: [[Dark Energy]].
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[[Image:600px-Albert Einstein Head.jpg|right|250px]]
[[Image:600px-Albert Einstein Head.jpg|right|250px]]
'''Albert Einstein''' (1879-1955) was the most famous [[physicist]] of the 20th century. He was born in Ulm, in Württemberg, [[Germany]] in a [[Judaism|Jewish]] family. During his stay at the [[Switzerland|Swiss]] [[Patent and Trademark Office|Patent Office]] Einstein produced much of his remarkable work. In 1905 he obtained his [[Doctor|doctor's degree]]. He won the [[Nobel Prize]] for his work on the [[photoelectric effect]] in 1921. <ref>[http://nobelprize.org/nobel_prizes/physics/laureates/1921/ "The Nobel Prize in Physics, 1921"] (2014). Nobelprize.org. Retrieved on January 23, 2015.</ref> Einstein [[Immigration|immigrated]] to the [[United States of America|United States]] in the late 1930s to take the position of Professor of Theoretical Physics at [[Princeton University|Princeton]]; upon the urging of a colleague in physics, recommended that [[President of the United States of America|President]] [[Franklin Roosevelt|Franklin D. Roosevelt]] develop an [[atomic bomb]] project. <ref>Einstein, Albert (August 2, 1939). [http://www.dannen.com/ae-fdr.html "Letter to F. D. Roosevelt, President of the United States"]. www.dannen.com. Retrieved from "Leo Szilard Online: Einstein's Letter to Roosevelt, August 2, 1939" on January 23, 2015.</ref> He later regretted this and became a passionate [[Pacifism|pacifist]]. In 1952, he was offered the Presidency of [[Israel]], but he turned it down. Einstein collaborated with Dr. Chaim Weizmann in establishing the [[Hebrew]] [[University]] of [[Jerusalem]]. Albert Einstein died on April 18, 1955 at Princeton, [[New Jersey]] at the age of 76.
'''Albert Einstein''' (1879-1955) was the most famous [[physicist]] of the 20th century. He was born in Ulm, in Württemberg, [[Germany]] in a [[Judaism|Jewish]] family. During his stay at the [[Switzerland|Swiss]] [[Patent and Trademark Office|Patent Office]] Einstein produced much of his remarkable work. In 1905 he obtained his [[Doctor|doctor's degree]]. He won the [[Nobel Prize]] for his work on the [[photoelectric effect]] in 1921. <ref>[http://nobelprize.org/nobel_prizes/physics/laureates/1921/ "The Nobel Prize in Physics, 1921"] (2014). Nobelprize.org. Retrieved on January 23, 2015.</ref> Einstein [[Immigration|immigrated]] to the [[United States of America|United States]] in the late 1930s to take the position of Professor of Theoretical Physics at [[Princeton University|Princeton]]; upon the urging of a colleague in physics, recommended that [[President of the United States of America|President]] [[Franklin Roosevelt|Franklin D. Roosevelt]] develop an [[atomic bomb]] project. <ref>Einstein, Albert (August 2, 1939). [http://www.dannen.com/ae-fdr.html "Letter to F. D. Roosevelt, President of the United States"]. www.dannen.com. Retrieved from "Leo Szilard Online: Einstein's Letter to Roosevelt, August 2, 1939" on January 23, 2015.</ref> He later regretted this and became a passionate [[Pacifism|pacifist]]. In 1952, he was offered the Presidency of [[Israel]], but he turned it down. Einstein collaborated with Dr. Chaim Weizmann in establishing the [[Hebrew]] [[University]] of [[Jerusalem]]. Albert Einstein died on April 18, 1955 at Princeton, [[New Jersey]] at the age of 76.
== Writings ==
== Writings ==