Difference between revisions of "Moon"

Revision as of 00:45, October 3, 2009

Mooning is fun. Go on, show your butt to the world. It's funny.

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-{{Planet|image=Moon2.jpg
+Mooning is fun. Go on, show your  butt to the world. It's funny.
-|caption=The Moon one week after [[full moon]]
-|primary=Earth
-|periapsis=363,300 km<ref name=moonfact>"[http://nssdc.gsfc.nasa.gov/planetary/factsheet/moonfact.html Moon Fact Sheet]," [[NASA]], April 19, 2007. Accessed May 3, 2008.</ref>
-|apoapsis=405,500 km<ref name=moonfact/>
-|semimajor=384,400 km<ref name=moonfact/><ref name=ssdorbit>"[http://ssd.jpl.nasa.gov/?sat_elem Planetary Satellite Mean Orbital Parameters]." [[Jet Propulsion Laboratory|JPL]], [[National Aeronautics and Space Administration|NASA]]. Accessed March 25, 2008.</ref>
-|orbitradius=378,000 km
-|eccentricity=0.0549<ref name=moonfact/><ref name=ssdorbit/>
-|sidereal=27.3217 da
-|synodic=29.530588 da
-|orbitspeed=1.023 km/s
-|inclination=18.28°<ref name=moonfact/>
-|siderealday=27.3217 da<ref name=moonfact/><ref name=ssdorbit/>
-|solarday=29.530588 da
-|mass=7.35 * 10<sup>22</sup> (1.23% earth)<ref name=moonfact/>
-|density=3350 kg/m³<ref name=ssdphys>"[http://ssd.jpl.nasa.gov/?sat_phys_par Planetary Satellite Physical Parameters]." [[Jet Propulsion Laboratory|JPL]], [[National Aeronautics and Space Administration|NASA]]. Accessed March 25, 2008.</ref>
-|surfacegrav=1.62 m/s² (0.165 ''g'')<ref name=moonfact/>
-|escapespeed=2.38 km/s<ref name=moonfact/>
-|meanradius=1737.1 km<ref name=moonfact/><ref name=ssdphys/>
-|equatorradius =1738.1 km<ref name=moonfact/>
-|polarradius =1736.0 km<ref name=moonfact/>
-|surfacearea=37,919,000 km² (7.434% earth)
-|mintemp=100 K
-|meantemp=250 K
-|maxtemp=400 K
-|albedo=0.12<ref name=moonfact/>
-|pmdm=1.3 * 10<sup>15</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>
-|cmdm=1.73 * 10<sup>22</sup> N-m/T<ref name=Humphreys/>
-|mdt=364 a<ref name=Humphreys/>
-|mhl=252.3 a<ref name=calc>Calculated</ref>
-}}The '''Moon''' is a natural [[satellite]] orbiting the [[Earth]] at an average distance of about 238,000 miles (380,000 km).
-Unlike most planets in the [[solar system]], [[Earth]] has only one moon. To those on Earth the Moon appears as a pale disc which goes through phases in which greater or lesser amounts of the side lit by the sun are visible from Earth.
-==The Moon as God's creation==
-The Earth's moon has several striking characteristics. To many Christians, these characteristics appear as "clues" or "hints" left by God for men to discover. <ref>http://www.math.nus.edu.sg/aslaksen/gem-projects/hm/0102-1-phase/CALENDARS.htm</ref>
-===Size of its disc===
-The Moon appears to have approximately the same size as the [[Sun]] when viewed from Earth.  This creates a unique symmetry and phenomenal [[solar eclipse|solar eclipses]].  The odds of this occurring by chance are nearly zero.
-===Rotation and revolution===
-The Moon presents the same side to [[Earth]] at all times.  That means that the rotation of the Earth offsets the separate effects of the revolution of the Moon. Physical explanations rely on [[tidal locking]], asserting that tidal forces on Earth caused a bulge on the Moon, thereby creating a drag on the rotation of the Moon until its same face always presents to the Earth.<ref> The same theory suggested that the planet [[Mercury]] had a similar locked rotation due to gravitational forces from the sun, such that the same side of Mercury always faces the sun. In fact, that is false.  [[Mercury]]'s tidal locking is incomplete and it does not always present the same face to the sun.</ref>  In fact, current tidal forces exerted by the [[Earth]] on the Moon cannot account fully for its bulge or egg shape.<ref>"[http://physics.fortlewis.edu/Astronomy/astronomy%20today/CHAISSON/AT308/HTML/AT30803.HTM Chapter 8, Section 3: The Rotation of the Moon]," "Astronomy Today", Department of Physics, Fort Lewis College, Durango, [[Colorado|CO]]. Accessed February 18, 2008</ref>
-===Origin theories===
-Most astronomers assert that the Moon originated from a collision early in Earth's history which created an orbiting ring of debris from the [[iron]]-poor surface of the planet which eventually coalesced into the moon.<ref>http://www.astronomy.com/asy/default.aspx?c=a&id=2198</ref> This theory, however, is contrary to key observations of the Moon, such as the relatively low levels of [[iron]] in the Moon's crust.<ref>J. H. Jones: [http://www.lpi.usra.edu/meetings/origin98/pdf/4045.pdf Tests of the Giant Impact Hypothesis]</ref><br />Biblical history records the Moon being created on the fourth day of [[creation week]], along with the Sun.
-===Rate of recession===
-The Moon currently recedes from the Earth at a rate of 1.5 inches (3.8 cm) per year<ref>NASA [http://sunearth.gsfc.nasa.gov/eclipse/SEhelp/ApolloLaser.html Measuring the Moon's Distance], LPI Bulletin, No. 72, August, 1994.</ref>, and is believed by mainstream scientists to be 4.6 billion years old <ref>NASA, [http://history.nasa.gov/SP-350/ch-15-2.html Apollo Expeditions to the Moon], Chapter 15.2.</ref>.<br />The Moon could never have been closer than about 11,000 miles or it would have been broken up by tidal forces.<ref name="js">Sarfati, Jonathan, [http://www.creationontheweb.com/content/view/764/ The moon: the light that rules the night], ''Creation'' 20(4):36–39, September 1998.</ref><br />If the rate of recession stayed constant at 3.8 cm per year, it would take 9.6 billion years for the lunar distance to migrate from 11,000 miles to the present distance of about 240,000 miles.<br />
-===Impact Craters===
-Astronomers assume that crater impacts are a reliable indicator of the age of a celestial body. True to the form and principles of [[uniformitarianism]] (as applied to [[astronomy]] rather than to [[geology]]), any such estimation relies upon uniform constants and weather/erosion trends. Recent research into crater impacts on the moon suggests that many of the assumptions previously made are unwarranted. Bonnie Buratti of NASA's Jet Propulsion Laboratory has asserted that space weathering "takes place very rapidly on the Moon."<ref>David, Leonard. "[http://www.space.com/missionlaunches/lunar_impact_021214.html Lunar Crash of 1953: Impact Crater Identified]." <http://www.space.com>, December 14, 2002. Accessed January 16, 2008.</ref> Peter Brown of the University of Western Ontario insists that there is no absolute criteria for the dating of craters.<ref>Hecht, Jeff. "[http://www.newscientist.com/article.ns?id=dn3242 New crater revives Moon mystery]." <http://www.newscientist.com>, January 11, 2003. Accessed January 16, 2008.</ref>
-===Creationist models===
-Danny Faulkner of the [[Institute for Creation Research]] has observed that many of the lunar maria contain ''ghost craters'', or craters that the lava flow that produced the maria seem to have filled only partially. In the [[deep time]] scale required by [[uniformitarianism]], the ghost craters are the result of impacts that occurred as much as half a gigayear before the crust-fracturing impacts that caused the lava flows.<ref name=Henderson>Henderson, Thomas H. "[http://www.hal-pc.org/~tom/HeavyCratering.html Do heavily cratered planets and moons demand an old age for the solar system]?" ''Tom Henderson's Creation Resources'', July 25, 2003. Accessed March 25, 2008.</ref> This is not a reasonable assumption, because any impact strong enough to crack the crust should have obliterated any craters previously extant. Faulkner thus concludes that the impacts that formed the ghost craters, and those that let loose the lava flows that formed the maria, occurred within days of one another<ref name=Faulkner1>Faulkner, Danny. "[http://www.icr.org/research/index/researchp_df_r01/ The Current State of Creation Astronomy]." ''Proceedings of the Fourth International Conference on Creationism,'' Creation Science Fellowship, Pittsburgh, pp. 201–216, August 3-8, 1998. Hosted at ''[[Institute for Creation Research]].'' Accessed March 25, 2008.</ref> and were probably part of at least one system-wide catastrophe involving a narrow stream of meteoroids and/or comets that delivered a concentrated bombardment of the Earth and Moon in a short interval.<ref name=Faulkner2>Faulkner, Danny. "[http://creationontheweb.com/content/view/1637 A Biblically-based cratering theory]." ''Technical Journal'' (now ''Journal of Creation''), 13(1):100-104, April 1999.</ref>
-Faulkner assumes that this system-wide catastrophe occurred during the year of the [[Great Flood]]. But in 1984, Russell Humphreys, then at the Sandia National Laboratories, developed evidence suggesting different dates entirely. Specifically, the [[Project Apollo]] exploration teams brought back many samples of [[basalt]] (an [[igneous rock]]) and [[brecchia]] (pulverized meteor-impact remains). Geologists analyzed both types of samples and found evidence that each type of rock had once been in a magnetic field far more powerful than that which the Moon has today. Using his model for the creation and decay of magnetic fields<ref name=Humphreys/>, Humphreys determined that the basalt had been laid down about 370 years after creation, and the brecchia had been laid down 1840 years after creation, or about 190 years after the Flood.<ref name=Humphreys2>Humphreys reasoned that the higher the magnetic dipole moment of the samples, the earlier in lunar history they were formed.</ref> These findings clearly suggest that the Moon, and presumably all other bodies in the solar system, have been subject to two separate system-wide bombardments, one occurring in the second or third generation after the [[fall of man]] and the other occurring well after the Flood.
-==Tides==
-The gravitational force of the Moon causes the ocean [[tides]]; these tidal forces have other effects as well. These tidal forces have the effect of creating resistance which slows down the rotation of both objects. In the case of the Earth, the result is that the Earth's rotation slows on the order of one millisecond per century. The Moon's rotation is locked in to its period of revolution, and the same side of the Moon always faces the Earth.
-==The "dark" or far side==
-The phrase "the ''dark'' side of the Moon" is inaccurate because the Moon does rotate relative to the Sun, with the same period as its period of revolution, once every 29 days. Our view of the Moon from the Earth always shows the same side of the Moon, with the same markings and features. When the Moon is full, the entire side that faces us is experiencing lunar "day" and is lit by the Sun. Two weeks later, when the Moon is new, the side that faces us is experiencing solar "night" and is unlit (and virtually invisible).
-The far side of the moon is far more heavily cratered than the near, and the predominant type of cratering is consistent with brecchia-forming meteor impact. This would suggest that the far side suffered its bombardment in the latter of the two catastrophes that Humphreys suggests that the Moon has suffered.
-Due to a slight "wobble" in the lunar motion called ''libration,'' we actually see a little bit more than half of the Moon's surface; sometimes it is turned a bit one way and sometimes the other. However, nobody had any idea of what the far side of the Moon looked like until 1959, when a Soviet satellite photographed it and relayed pictures back.
-[[image:oldmooninnew.jpg|200px|right|thumb|The "old Moon in the new Moon's arms"]]
-In the old Scottish ballad ''Sir Patrick Spens''<ref>Child, Francis James (1860), ''The English and Scottish Popular Ballads,'' [http://www.sacred-texts.com/neu/eng/child/ch058.htm No. 58]; the ballad is thought to refer to an actual event of the year A.D. 1290.</ref>, a sailor cautions:
-:"I saw the new moon late yestreen
-::With the old moon in her arm;
-:And if we go to sea, master,
-::I fear we'll come to harm."
-==Earthshine==
-The effect known as "the old Moon in the new Moon's arms" can often be seen when the Moon is a narrow [[crescent]]. Within the intensely bright crescent, a dim and mysterious view of the entire circular moon is seen. The effect is also known as ''earthshine'' because it is light from the Sun reflected off the Earth to the Moon and back that lights up the darker portion of the Moon. The bright crescent is lit by the Sun and is in full daylight. The rest of the Moon is not lit by the Sun; but an [[astronaut]] standing in this area would see a "full Earth" dominating the nighttime sky, lighting it up by its earthshine. The brightness of Earthshine, and hence the visibility of the old Moon in the new Moon's arms, varies. When the Earth is covered with clouds, or when there is a lot of snow-pack on the side of the Earth facing the Moon, the Earth is a white and bright and the Earthshine is intense. When the Earth looks like a "big, blue marble," it is less intense.
-==Lunar calendars==
-Throughout history, many calendar systems have been based on the phases of the moon.
-The months of the [[Islam|Muslim]] [[calendar]] are determined by observations of the [[hilal]], the moment at which the thin crescent moon first becomes visible. This marks the start of a month. Traditionally, and today in [[Pakistan]] and [[Jordan]], hilal is determined by actual observation and can be affected by weather and other factors. When following the traditional method, it is not actually possible to be certain precisely when future months will begin. In most Muslim countries, actual observation has been replaced by [[astronomy|astronomical]] rules.
-==The moon in culture==
-"The Old Moon in the New Moon's Arms" is the title of a poem by [[Ella Wheeler Wilcox]], in which she interprets the effect as the New Moon wishing that her lost love, the Old Moon, be in her arms one last time; Venus grants the wish, and:
-:Swift thro' the vapors and the golden mist&mdash;<br>
-::The Full Moon's shadowy shape shone on the night,<br>
-:The New Moon reached out clasping arms and kissed<br>
-::Her phantom lover in the whole world's sight.<br>
-== Trivia==
-Although the Moon is often described as revolving around the Earth, this is slightly inaccurate: the Earth and the Moon ''both'' revolve around their ''barycenter'', their common [[centroid|center of mass]]. This point is 1,700 below the earth's surface, which is about 1/4 of the earth's [[radius]].<ref> The radius of the Earth is 6,378 kilometers, so that means that the barycenter is located INSIDE the Earth about 1707 kilometers below its surface. [http://www.astronomycafe.net/qadir/q665.html] </ref>
-The combined motion is like an athlete performing an [[Olympics| Olympic]] hammer throw: one object swings in a large circle, the other almost pivots around a fixed point but actually performs a small opposing circle of its own. <ref>The Earth and the Moon orbit each other around a gravitational midpoint called the ''barycenter.'' This point is, however, actually inside the Earth, about 3/4 of its radius from its center. It is not the Earth, but the barycenter of the Earth-Moon system, that orbits the [[Sun]] in a near-perfect ellipse. Relative to this ellipse, Earth is 3,000 miles closer to the Sun at full moon and 3,000 miles further from the Sun at new moon.</ref>
-When speaking of things having to do with the moon, the adjective ''lunar'' is used. The Greek-derived prefixed root ''selen-'' followed by the morpheme ''-o-'' is used as well; for example, the [[science]] of mapping the moon is called ''[[selenography]]'' (morphemes: ''selen-o-graph-y''). (Note, however, that the apsides of the orbits of the [[Project Apollo]] spacecraft were always called ''pericynthion'' and ''apocynthion'', not "periselene" and "aposelene.")
-== Other moons ==
-[[Image:Many_Moons.jpg|250px|left]]
-While the Moon of [[Earth]] is the best-known satellite of any [[planet]], other planets in our solar system also have moons. Earth has the least number of moons (one), while [[Jupiter]] has sixty-two. The first extraterrestrial moons to be discovered were the four Galilean moons ([[Io]], [[Europa (moon)|Europa]], [[Ganymede]], and [[Callisto]]. Next to these, Earth's Moon is one of the largest, but Jupiter and [[Saturn]] have moons in orbit about them that might qualify as planets if they orbited the [[Sun]] instead.
-=== Sizes of moons ===
-Most moons in the solar system are no larger than typical asteroids. They are of irregular shape, have light and variable surface gravities, and are often unstable in their orbits. [[Phobos]] and [[Deimos]], the moons of [[Mars]], fall into this category.
-Earth's own moon is an example of a [[dwarf planet]]-sized moon. These moons are so large that their own self-gravity forces them to collapse into spheres or spheroids. Some of them, like [[Ganymede]] and [[Titan (moon)|Titan]], are larger even than the planet [[Mercury]]. Earth's moon was, of course, known to the ancients, but the remaining dwarf-planet-sized moons were generally the first to be discovered in orbit around any given primary. [[Galileo Galilei]] discovered the first four of these in orbit about [[Jupiter]] early in the seventeenth century; [[Christiaan Huygens]] then discovered Titan of [[Saturn]] later in that same century.
-== Symbolic Importance in Islam ==
-The crescent moon is an internationally recognized symbol of [[Islam]].  It appears on the flags of several Islamic nations.  It also forms part of the official emblems of the International Red Cross and Red Crescent Societies. <ref>http://islam.about.com/od/history/a/crescent_moon.htm</ref>
-== See also ==
-*[[Origin of the Moon]]
-== External links ==
-*[http://www.solarviews.com/eng/terms.htm Glossary]
-==Further reading==
-*  Donna Henes. ''The Moon Watcher's Companion: Everything You Ever Wanted to Know About the Moon, and More'' (2004) [http://www.amazon.com/Moon-Watchers-Companion-Everything-Wanted/dp/1569244669/ref=sr_1_11?ie=UTF8&s=books&qid=1241592218&sr=1-11 excerpt and text search]
-* David Schrunk et al. ''The Moon: Resources, Future Development and Settlement'' (2007) [http://www.amazon.com/Moon-Resources-Development-Settlement-Exploration/dp/0387360557/ref=sr_1_12?ie=UTF8&s=books&qid=1241592379&sr=1-12 excerpt and text search]
-* Seymour Simon, ''The Moon'' (2003) [http://www.amazon.com/Moon-Seymour-Simon/dp/0689835639/ref=sr_1_1?ie=UTF8&s=books&qid=1241592218&sr=1-1 excerpt and text search]
-== Notes and References ==
-{{reflist|2}}
-{{Solarsystem}}
-[[Category:Astronomy]]

Difference between revisions of "Moon"

Revision as of 00:45, October 3, 2009

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