Moon - wikipedia Moon This article is about Earth 's natural satellite. For moons in general, see natural satellite. For other uses, see Moon ( disambiguation ). Moon Full moon as seen from North America in Earth 's Northern Hemisphere Designations Adjectives Lunar selenic Orbital characteristics Perigee 362 600 km ( 356 400 -- 370 400 km ) Apogee 405 400 km ( 404 000 -- 406 700 km ) Semi-major axis 7008384399000000000 ♠ 384 399 km ( 7008384466527698999 ♠ 0.002 57 AU ) Eccentricity 6998549000000000000 ♠ 0.0549 Orbital period 7006236059151040000 ♠ 27.321 661 d ( 27 d 7 h 43 min 11.5 s ) Synodic period 7006255144288960000 ♠ 29.530 589 d ( 29 d 12 h 44 min 2.9 s ) Average orbital speed 7003102200000000000 ♠ 1.022 km / s Inclination 5.145 ° to the ecliptic Longitude of ascending node Regressing by one revolution in 18.61 years Argument of perigee Progressing by one revolution in 8.85 years Satellite of Earth Physical characteristics Mean radius 7006173710000000000 ♠ 1737. 1 km ( 0.273 of Earth 's ) Equatorial radius 7006173810000000000 ♠ 1738. 1 km ( 0.273 of Earth 's ) Polar radius 7006173600000000000 ♠ 1736. 0 km ( 0.273 of Earth 's ) Flattening 6997119999999999999 ♠ 0.0012 Circumference 7007109210000000000 ♠ 10 921 km ( equatorial ) Surface area 7013379300000000000 ♠ 3.793 × 10 km ( 0.074 of Earth 's ) Volume 7019219580000000000 ♠ 2.1958 × 10 km ( 0.020 of Earth 's ) Mass 7022734200000000000 ♠ 7.342 × 10 kg ( 6998123000000000000 ♠ 0.012 300 of Earth 's ) Mean density 7003334400000000000 ♠ 3.344 g / cm 6999606000000000000 ♠ 0.606 × Earth Surface gravity 7000162000000000000 ♠ 1.62 m / s ( 6999165400000000000 ♠ 0.1654 g ) Moment of inertia factor 6999392900000000000 ♠ 0.3929 ± 0.0009 Escape velocity 7003238000000000000 ♠ 2.38 km / s Sidereal rotation period 7006236059151040000 ♠ 27.321 661 d ( synchronous ) Equatorial rotation velocity 4.627 m / s Axial tilt 1.5424 ° to ecliptic 6.687 ° to orbit plane Albedo 0.136 Surface temp. min mean max Equator 100 K 220 K 390 K 85 ° N 150 K 230 K Apparent magnitude − 2.5 to − 12.9 − 12.74 ( mean full moon ) Angular diameter 29.3 to 34.1 arcminutes Atmosphere Surface pressure 10 Pa ( 1 picobar ) ( day ) 10 Pa ( 1 femtobar ) ( night ) Composition by volume He Ar Ne Na Rn The Moon is an astronomical body that orbits planet Earth, being Earth 's only permanent natural satellite. It is the fifth - largest natural satellite in the Solar System, and the largest among planetary satellites relative to the size of the planet that it orbits ( its primary ). Following Jupiter 's satellite Io, the Moon is the second - densest satellite among those whose densities are known. The Moon is thought to have formed about 4.51 billion years ago, not long after Earth. The most widely accepted explanation is that the Moon formed from the debris left over after a giant impact between Earth and a Mars - sized body called Theia. The Moon is in synchronous rotation with Earth, always showing the same face, with its near side marked by dark volcanic maria that fill the spaces between the bright ancient crustal highlands and the prominent impact craters. As seen from the Earth, it is the second - brightest regularly visible celestial object in Earth 's sky, after the Sun. Its surface is actually dark, although compared to the night sky it appears very bright, with a reflectance just slightly higher than that of worn asphalt. Its gravitational influence produces the ocean tides, body tides, and the slight lengthening of the day. The Moon 's average orbital distance at the present time is 384,402 km ( 238,856 mi ), or 1.28 light - seconds. This is about thirty times the diameter of Earth, with its apparent size in the sky almost the same as that of the Sun ( due to it being 400x farther and larger ), resulting in the Moon covering the Sun nearly precisely in total solar eclipse. This matching of apparent visual size will not continue in the far future, because the Moon 's distance from Earth is slowly increasing. The Soviet Union 's Luna programme was the first to reach the Moon with unmanned spacecraft in 1959 ; the United States ' NASA Apollo program achieved the only manned missions to date, beginning with the first manned lunar orbiting mission by Apollo 8 in 1968, and six manned lunar landings between 1969 and 1972, with the first being Apollo 11. These missions returned lunar rocks which have been used to develop a geological understanding of the Moon 's origin, internal structure, and later history. Since the Apollo 17 mission in 1972, the Moon has been visited only by unmanned spacecraft. Within human culture, both the Moon 's natural prominence in the earthly sky, and its regular cycle of phases as seen from the Earth have provided cultural references and influences for human societies and cultures since time immemorial. Such cultural influences can be found in language, lunar based calendar systems, art, and mythology. Contents 1 Name and etymology 2 Formation 3 Physical characteristics 3.1 Internal structure 3.2 Surface geology 3.2. 1 Volcanic features 3.2. 2 Impact craters 3.2. 3 Lunar swirls 3.2. 4 Presence of water 3.3 Gravitational field 3.4 Magnetic field 3.5 Atmosphere 3.5. 1 Dust 3.5. 2 Past thicker atmosphere 3.6 Seasons 4 Relationship to Earth 4.1 Orbit 4.2 Relative size 4.3 Appearance from Earth 4.4 Tidal effects 4.5 Eclipses 5 Observation and exploration 5.1 Ancient and medieval studies 5.2 By spacecraft 5.2. 1 20th century 5.2. 1.1 Soviet missions 5.2. 1.2 United States missions 5.2. 1.3 1980s -- 2000 5.2. 2 21st century 5.2. 3 Planned commercial missions 6 Astronomy from the Moon 7 Legal status 8 In culture 8.1 Mythology 8.2 Calendar 8.3 Lunacy 9 See also 10 References 10.1 Notes 10.2 Citations 10.3 Bibliography 11 Further reading 12 External links 12.1 Cartographic resources 12.2 Observation tools 12.3 General Name and Etymology The Moon, tinted reddish, during a lunar eclipse See also : list of lunar deities The usual English proper name for Earth 's natural satellite is `` the Moon ''. The noun moon is derived from moone ( around 1380 ), which developed from mone ( 1135 ), which is derived from Old English mōna ( dating from before 725 ), which ultimately stems from Proto - Germanic * mǣnōn, like all Germanic language cognates. Occasionally, the name `` Luna '' is used. In literature, especially science fiction, `` Luna '' is used to distinguish it from other moons, while in poetry, the name has been used to denote personification of our moon. The principal modern English adjective pertaining to the Moon is lunar, derived from the Latin Luna. A less common adjective is selenic, derived from the Ancient Greek Selene ( Σελήνη ), from which is derived the prefix `` seleno - '' ( as in selenography ). Both the Greek Selene and the Roman goddess Diana were alternatively called Cynthia. The names Luna, Cynthia, and Selene are reflected in terminology for lunar orbits in words such as apolune, pericynthion, and selenocentric. The name Diana is connected to dies meaning ' day '. The Moon Near side of the Moon Far side of the Moon Lunar north pole Lunar south pole Formation Main articles : Origin of the Moon and Giant - impact hypothesis Several mechanisms have been proposed for the Moon 's formation 4.51 billion years ago, and some 60 million years after the origin of the Solar System. These mechanisms included the fission of the Moon from Earth 's crust through centrifugal force ( which would require too great an initial spin of Earth ), the gravitational capture of a pre-formed Moon ( which would require an unfeasibly extended atmosphere of Earth to dissipate the energy of the passing Moon ), and the co-formation of Earth and the Moon together in the primordial accretion disk ( which does not explain the depletion of metals in the Moon ). These hypotheses also can not account for the high angular momentum of the Earth -- Moon system. Play media The evolution of the Moon and a tour of the Moon The prevailing hypothesis is that the Earth -- Moon system formed as a result of the impact of a Mars - sized body ( named Theia ) with the proto - Earth ( giant impact ), that blasted material into orbit about the Earth that then accreted to form the present Earth - Moon system. The far side of the Moon has a crust that is 30 mi ( 48 km ) thicker than the near side of the Moon. This is thought to be due to the Moon having been amalgamated from two different bodies. This hypothesis, although not perfect, perhaps best explains the evidence. Eighteen months prior to an October 1984 conference on lunar origins, Bill Hartmann, Roger Phillips, and Jeff Taylor challenged fellow lunar scientists : `` You have eighteen months. Go back to your Apollo data, go back to your computer, do whatever you have to, but make up your mind. Do n't come to our conference unless you have something to say about the Moon 's birth. '' At the 1984 conference at Kona, Hawaii, the giant impact hypothesis emerged as the most popular. Before the conference, there were partisans of the three `` traditional '' theories, plus a few people who were starting to take the giant impact seriously, and there was a huge apathetic middle who did n't think the debate would ever be resolved. Afterward there were essentially only two groups : the giant impact camp and the agnostics. Giant impacts are thought to have been common in the early Solar System. Computer simulations of a giant impact have produced results that are consistent with the mass of the lunar core and the present angular momentum of the Earth -- Moon system. These simulations also show that most of the Moon derived from the impactor, rather than the proto - Earth. More recent simulations suggest a larger fraction of the Moon derived from the original Earth mass. Studies of meteorites originating from inner Solar System bodies such as Mars and Vesta show that they have very different oxygen and tungsten isotopic compositions as compared to Earth, whereas Earth and the Moon have nearly identical isotopic compositions. The isotopic equalization of the Earth - Moon system might be explained by the post-impact mixing of the vaporized material that formed the two, although this is debated. The great amount of energy released in the impact event and the subsequent re-accretion of that material into the Earth - Moon system would have melted the outer shell of Earth, forming a magma ocean. Similarly, the newly formed Moon would also have been affected and had its own lunar magma ocean ; estimates for its depth range from about 500 km ( 300 miles ) to its entire depth ( 1,737 km ( 1,079 miles ) ). While the giant impact hypothesis might explain many lines of evidence, there are still some unresolved questions, most of which involve the Moon 's composition. Oceanus Procellarum ( `` Ocean of Storms '' ) Ancient rift valleys -- rectangular structure ( visible -- topography -- GRAIL gravity gradients ) Ancient rift valleys -- context. Ancient rift valleys -- closeup ( artist 's concept ). In 2001, a team at the Carnegie Institute of Washington reported the most precise measurement of the isotopic signatures of lunar rocks. To their surprise, the team found that the rocks from the Apollo program carried an isotopic signature that was identical with rocks from Earth, and were different from almost all other bodies in the Solar System. Because most of the material that went into orbit to form the Moon was thought to come from Theia, this observation was unexpected. In 2007, researchers from the California Institute of Technology announced that there was less than a 1 % chance that Theia and Earth had identical isotopic signatures. Published in 2012, an analysis of titanium isotopes in Apollo lunar samples showed that the Moon has the same composition as Earth, which conflicts with what is expected if the Moon formed far from Earth 's orbit or from Theia. Variations on the giant impact hypothesis may explain this data. Physical characteristics Internal structure Main article : Internal structure of the Moon Structure of the Moon Chemical composition of the lunar surface regolith ( derived from crustal rocks ) Compound Formula Composition ( wt % ) Maria Highlands silica SiO 45.4 % 45.5 % alumina Al O 14.9 % 24.0 % lime CaO 11.8 % 15.9 % iron ( II ) oxide FeO 14.1 % 5.9 % magnesia MgO 9.2 % 7.5 % titanium dioxide TiO 3.9 % 0.6 % sodium oxide Na O 0.6 % 0.6 % Total 99.9 % 100.0 % The Moon is a differentiated body : it has a geochemically distinct crust, mantle, and core. The Moon has a solid iron - rich inner core with a radius possibly as small as 240 km ( 150 mi ) and a fluid outer core primarily made of liquid iron with a radius of roughly 300 km ( 190 mi ). Around the core is a partially molten boundary layer with a radius of about 500 km ( 310 mi ). This structure is thought to have developed through the fractional crystallization of a global magma ocean shortly after the Moon 's formation 4.5 billion years ago. Crystallization of this magma ocean would have created a mafic mantle from the precipitation and sinking of the minerals olivine, clinopyroxene, and orthopyroxene ; after about three - quarters of the magma ocean had crystallised, lower - density plagioclase minerals could form and float into a crust atop. The final liquids to crystallise would have been initially sandwiched between the crust and mantle, with a high abundance of incompatible and heat - producing elements. Consistent with this perspective, geochemical mapping made from orbit suggests the crust of mostly anorthosite. The Moon rock samples of the flood lavas that erupted onto the surface from partial melting in the mantle confirm the mafic mantle composition, which is more iron rich than that of Earth. The crust is on average about 50 km ( 31 mi ) thick. The Moon is the second - densest satellite in the Solar System, after Io. However, the inner core of the Moon is small, with a radius of about 350 km ( 220 mi ) or less, around 20 % of the radius of the Moon. Its composition is not well defined, but is probably metallic iron alloyed with a small amount of sulfur and nickel ; analyses of the Moon 's time - variable rotation suggest that it is at least partly molten. Surface geology Main articles : Geology of the Moon and Moon rocks Topography of the Moon The topography of the Moon has been measured with laser altimetry and stereo image analysis. Its most visible topographic feature is the giant far - side South Pole -- Aitken basin, some 2,240 km ( 1,390 mi ) in diameter, the largest crater on the Moon and the second - largest confirmed impact crater in the Solar System. At 13 km ( 8.1 mi ) deep, its floor is the lowest point on the surface of the Moon. The highest elevations of the Moon 's surface are located directly to the northeast, and it has been suggested might have been thickened by the oblique formation impact of the South Pole -- Aitken basin. Other large impact basins, such as Imbrium, Serenitatis, Crisium, Smythii, and Orientale, also possess regionally low elevations and elevated rims. The far side of the lunar surface is on average about 1.9 km ( 1.2 mi ) higher than that of the near side. The discovery of fault scarp cliffs by the Lunar Reconnaissance Orbiter suggest that the Moon has shrunk within the past billion years, by about 90 metres ( 300 ft ). Similar shrinkage features exist on Mercury. Volcanic features Main article : Lunar mare Lunar nearside with major maria and craters labeled The dark and relatively featureless lunar plains, clearly seen with the naked eye, are called maria ( Latin for `` seas '' ; singular mare ), as they were once believed to be filled with water ; they are now known to be vast solidified pools of ancient basaltic lava. Although similar to terrestrial basalts, lunar basalts have more iron and no minerals altered by water. The majority of these lavas erupted or flowed into the depressions associated with impact basins. Several geologic provinces containing shield volcanoes and volcanic domes are found within the near side `` maria ''. Evidence of young lunar volcanism Almost all maria are on the near side of the Moon, and cover 31 % of the surface of the near side, compared with 2 % of the far side. This is thought to be due to a concentration of heat - producing elements under the crust on the near side, seen on geochemical maps obtained by Lunar Prospector 's gamma - ray spectrometer, which would have caused the underlying mantle to heat up, partially melt, rise to the surface and erupt. Most of the Moon 's mare basalts erupted during the Imbrian period, 3.0 -- 3.5 billion years ago, although some radiometrically dated samples are as old as 4.2 billion years. Until recently, the youngest eruptions, dated by crater counting, appeared to have been only 1.2 billion years ago. In 2006, a study of Ina, a tiny depression in Lacus Felicitatis, found jagged, relatively dust - free features that, due to the lack of erosion by infalling debris, appeared to be only 2 million years old. Moonquakes and releases of gas also indicate some continued lunar activity. In 2014 NASA announced `` widespread evidence of young lunar volcanism '' at 70 irregular mare patches identified by the Lunar Reconnaissance Orbiter, some less than 50 million years old. This raises the possibility of a much warmer lunar mantle than previously believed, at least on the near side where the deep crust is substantially warmer due to the greater concentration of radioactive elements. Just prior to this, evidence has been presented for 2 -- 10 million years younger basaltic volcanism inside Lowell crater, Orientale basin, located in the transition zone between the near and far sides of the Moon. An initially hotter mantle and / or local enrichment of heat - producing elements in the mantle could be responsible for prolonged activities also on the far side in the Orientale basin. The lighter - coloured regions of the Moon are called terrae, or more commonly highlands, because they are higher than most maria. They have been radiometrically dated to having formed 4.4 billion years ago, and may represent plagioclase cumulates of the lunar magma ocean. In contrast to Earth, no major lunar mountains are believed to have formed as a result of tectonic events. The concentration of maria on the Near Side likely reflects the substantially thicker crust of the highlands of the Far Side, which may have formed in a slow - velocity impact of a second moon of Earth a few tens of millions of years after their formation. Impact craters Further information : List of craters on the Moon Lunar crater Daedalus on the Moon 's far side The other major geologic process that has affected the Moon 's surface is impact cratering, with craters formed when asteroids and comets collide with the lunar surface. There are estimated to be roughly 300,000 craters wider than 1 km ( 0.6 mi ) on the Moon 's near side alone. The lunar geologic timescale is based on the most prominent impact events, including Nectaris, Imbrium, and Orientale, structures characterized by multiple rings of uplifted material, between hundreds and thousands of kilometres in diameter and associated with a broad apron of ejecta deposits that form a regional stratigraphic horizon. The lack of an atmosphere, weather and recent geological processes mean that many of these craters are well - preserved. Although only a few multi-ring basins have been definitively dated, they are useful for assigning relative ages. Because impact craters accumulate at a nearly constant rate, counting the number of craters per unit area can be used to estimate the age of the surface. The radiometric ages of impact - melted rocks collected during the Apollo missions cluster between 3.8 and 4.1 billion years old : this has been used to propose a Late Heavy Bombardment of impacts. Blanketed on top of the Moon 's crust is a highly comminuted ( broken into ever smaller particles ) and impact gardened surface layer called regolith, formed by impact processes. The finer regolith, the lunar soil of silicon dioxide glass, has a texture resembling snow and a scent resembling spent gunpowder. The regolith of older surfaces is generally thicker than for younger surfaces : it varies in thickness from 10 -- 20 km ( 6.2 -- 12.4 mi ) in the highlands and 3 -- 5 km ( 1.9 -- 3.1 mi ) in the maria. Beneath the finely comminuted regolith layer is the megaregolith, a layer of highly fractured bedrock many kilometres thick. Comparison of high - resolution images obtained by the Lunar Reconnaissance Orbiter has shown a contemporary crater - production rate significantly higher than previously estimated. A secondary cratering process caused by distal ejecta is thought to churn the top two centimetres of regolith a hundred times more quickly than previous models suggested -- on a timescale of 81,000 years. Lunar swirls at Reiner Gamma Lunar swirls Main article : Lunar swirls Lunar swirls are enigmatic features found across the Moon 's surface, which are characterized by a high albedo, appearing optically immature ( i.e. the optical characteristics of a relatively young regolith ), and often displaying a sinuous shape. Their curvilinear shape is often accentuated by low albedo regions that wind between the bright swirls. Presence of water Main article : Lunar water Liquid water can not persist on the lunar surface. When exposed to solar radiation, water quickly decomposes through a process known as photodissociation and is lost to space. However, since the 1960s, scientists have hypothesized that water ice may be deposited by impacting comets or possibly produced by the reaction of oxygen - rich lunar rocks, and hydrogen from solar wind, leaving traces of water which could possibly persist in cold, permanently shadowed craters at either pole on the Moon. Computer simulations suggest that up to 14,000 km ( 5,400 sq mi ) of the surface may be in permanent shadow. The presence of usable quantities of water on the Moon is an important factor in rendering lunar habitation as a cost - effective plan ; the alternative of transporting water from Earth would be prohibitively expensive. In years since, signatures of water have been found to exist on the lunar surface. In 1994, the bistatic radar experiment located on the Clementine spacecraft, indicated the existence of small, frozen pockets of water close to the surface. However, later radar observations by Arecibo, suggest these findings may rather be rocks ejected from young impact craters. In 1998, the neutron spectrometer on the Lunar Prospector spacecraft showed that high concentrations of hydrogen are present in the first meter of depth in the regolith near the polar regions. Volcanic lava beads, brought back to Earth aboard Apollo 15, showed small amounts of water in their interior. The 2008 Chandrayaan - 1 spacecraft has since confirmed the existence of surface water ice, using the on - board Moon Mineralogy Mapper. The spectrometer observed absorption lines common to hydroxyl, in reflected sunlight, providing evidence of large quantities of water ice, on the lunar surface. The spacecraft showed that concentrations may possibly be as high as 1,000 ppm. In 2009, LCROSS sent a 2,300 kg ( 5,100 lb ) impactor into a permanently shadowed polar crater, and detected at least 100 kg ( 220 lb ) of water in a plume of ejected material. Another examination of the LCROSS data showed the amount of detected water to be closer to 155 ± 12 kg ( 342 ± 26 lb ). In May 2011, 615 -- 1410 ppm water in melt inclusions in lunar sample 74220 was reported, the famous high - titanium `` orange glass soil '' of volcanic origin collected during the Apollo 17 mission in 1972. The inclusions were formed during explosive eruptions on the Moon approximately 3.7 billion years ago. This concentration is comparable with that of magma in Earth 's upper mantle. Although of considerable selenological interest, this announcement affords little comfort to would - be lunar colonists -- the sample originated many kilometers below the surface, and the inclusions are so difficult to access that it took 39 years to find them with a state - of - the - art ion microprobe instrument. Gravitational field Main article : Gravity of the Moon GRAIL 's gravity map of the Moon The gravitational field of the Moon has been measured through tracking the Doppler shift of radio signals emitted by orbiting spacecraft. The main lunar gravity features are mascons, large positive gravitational anomalies associated with some of the giant impact basins, partly caused by the dense mare basaltic lava flows that fill those basins. The anomalies greatly influence the orbit of spacecraft about the Moon. There are some puzzles : lava flows by themselves can not explain all of the gravitational signature, and some mascons exist that are not linked to mare volcanism. Magnetic field Main article : Magnetic field of the Moon The Moon has an external magnetic field of about 1 -- 100 nanoteslas, less than one - hundredth that of Earth. It does not currently have a global dipolar magnetic field and only has crustal magnetization, probably acquired early in lunar history when a dynamo was still operating. Alternatively, some of the remnant magnetization may be from transient magnetic fields generated during large impact events through the expansion of an impact - generated plasma cloud in the presence of an ambient magnetic field. This is supported by the apparent location of the largest crustal magnetizations near the antipodes of the giant impact basins. Atmosphere Main article : Atmosphere of the Moon Sketch by the Apollo 17 astronauts. The lunar atmosphere was later studied by LADEE. The Moon has an atmosphere so tenuous as to be nearly vacuum, with a total mass of less than 10 metric tons ( 9.8 long tons ; 11 short tons ). The surface pressure of this small mass is around 3 × 10 atm ( 0.3 nPa ) ; it varies with the lunar day. Its sources include outgassing and sputtering, a product of the bombardment of lunar soil by solar wind ions. Elements that have been detected include sodium and potassium, produced by sputtering ( also found in the atmospheres of Mercury and Io ) ; helium - 4 and neon from the solar wind ; and argon - 40, radon - 222, and polonium - 210, outgassed after their creation by radioactive decay within the crust and mantle. The absence of such neutral species ( atoms or molecules ) as oxygen, nitrogen, carbon, hydrogen and magnesium, which are present in the regolith, is not understood. Water vapour has been detected by Chandrayaan - 1 and found to vary with latitude, with a maximum at ~ 60 -- 70 degrees ; it is possibly generated from the sublimation of water ice in the regolith. These gases either return into the regolith due to the Moon 's gravity or are lost to space, either through solar radiation pressure or, if they are ionized, by being swept away by the solar wind 's magnetic field. Dust A permanent asymmetric moon dust cloud exists around the Moon, created by small particles from comets. Estimates are 5 tons of comet particles strike the Moon 's surface each 24 hours. The particles strike the Moon 's surface ejecting moon dust above the Moon. The dust stays above the Moon approximately 10 minutes, taking 5 minutes to rise, and 5 minutes to fall. On average, 120 kilograms of dust are present above the Moon, rising to 100 kilometers above the surface. The dust measurements were made by LADEE 's Lunar Dust EXperiment ( LDEX ), between 20 and 100 kilometers above the surface, during a six - month period. LDEX detected an average of one 0.3 micrometer moon dust particle each minute. Dust particle counts peaked during the Geminid, Quadrantid, Northern Taurid, and Omicron Centaurid meteor showers, when the Earth, and Moon, pass through comet debris. The cloud is asymmetric, more dense near the boundary between the Moon 's dayside and nightside. Past thicker atmosphere In October 2017, NASA scientists at the Marshall Space Flight Center and the Lunar and Planetary Institute in Houston announced their finding, based on studies of Moon magma samples retrieved by the Apollo missions, that the Moon had once possessed a relatively thick atmosphere for a period of 70 million years between 3 and 4 billion years ago. This atmosphere, sourced from gases ejected from lunar volcanic eruptions, was twice the thickness of that of present - day Mars. The ancient lunar atmosphere was eventually stripped away by solar winds and dissipated into space. Seasons The Moon 's axial tilt with respect to the ecliptic is only 1.5424 °, much less than the 23.44 ° of Earth. Because of this, the Moon 's solar illumination varies much less with season, and topographical details play a crucial role in seasonal effects. From images taken by Clementine in 1994, it appears that four mountainous regions on the rim of Peary Crater at the Moon 's north pole may remain illuminated for the entire lunar day, creating peaks of eternal light. No such regions exist at the south pole. Similarly, there are places that remain in permanent shadow at the bottoms of many polar craters, and these `` craters of eternal darkness '' are extremely cold : Lunar Reconnaissance Orbiter measured the lowest summer temperatures in craters at the southern pole at 35 K ( − 238 ° C ; − 397 ° F ) and just 26 K ( − 247 ° C ; − 413 ° F ) close to the winter solstice in north polar Hermite Crater. This is the coldest temperature in the Solar System ever measured by a spacecraft, colder even than the surface of Pluto. Average temperatures of the Moon 's surface are reported, but temperatures of different areas will vary greatly depending upon whether they are in sunlight or shadow. Relationship to Earth Orbit Main articles : Orbit of the Moon and Lunar theory Earth -- Moon system ( schematic ) DSCOVR satellite sees the Moon passing in front of Earth The Moon makes a complete orbit around Earth with respect to the fixed stars about once every 27.3 days ( its sidereal period ). However, because Earth is moving in its orbit around the Sun at the same time, it takes slightly longer for the Moon to show the same phase to Earth, which is about 29.5 days ( its synodic period ). Unlike most satellites of other planets, the Moon orbits closer to the ecliptic plane than to the planet 's equatorial plane. The Moon 's orbit is subtly perturbed by the Sun and Earth in many small, complex and interacting ways. For example, the plane of the Moon 's orbit gradually rotates once every 18.61 years, which affects other aspects of lunar motion. These follow - on effects are mathematically described by Cassini 's laws. Relative size The Moon is exceptionally large relative to Earth : a quarter its diameter and 1 / 81 its mass. It is the largest moon in the Solar System relative to the size of its planet, though Charon is larger relative to the dwarf planet Pluto, at 1 / 9 Pluto 's mass. Earth and the Moon are nevertheless still considered a planet -- satellite system, rather than a double planet, because their barycentre, the common centre of mass, is located 1,700 km ( 1,100 mi ) ( about a quarter of Earth 's radius ) beneath Earth 's surface. Appearance from Earth See also : Lunar phase, Earthshine, and Lunar observation Moon setting in western sky over the High Desert in California Moon above Makarska, Croatia The Moon is in synchronous rotation : it rotates about its axis in about the same time it takes to orbit Earth. This results in it always keeping nearly the same face turned towards Earth. However, due to the effect of libration, about 59 % of the Moon 's surface can actually be seen from Earth. The Moon used to rotate at a faster rate, but early in its history, its rotation slowed and became tidally locked in this orientation as a result of frictional effects associated with tidal deformations caused by Earth. With time, the energy of rotation of the Moon on its axis was dissipated as heat, until there was no rotation of the Moon relative to the Earth. The side of the Moon that faces Earth is called the near side, and the opposite the far side. The far side is often inaccurately called the `` dark side '', but it is in fact illuminated as often as the near side : once per lunar day, during the new moon phase we observe on Earth when the near side is dark. In 2016, planetary scientists, using data collected on the much earlier Nasa Lunar Prospector mission, found two hydrogen - rich areas on opposite sides of the Moon, probably in the form of water ice. It is speculated that these patches were the poles of the Moon billions of years ago, before it was tidally locked to Earth. The Moon has an exceptionally low albedo, giving it a reflectance that is slightly brighter than that of worn asphalt. Despite this, it is the brightest object in the sky after the Sun. This is partly due to the brightness enhancement of the opposition effect ; at quarter phase, the Moon is only one - tenth as bright, rather than half as bright, as at full moon. Additionally, colour constancy in the visual system recalibrates the relations between the colours of an object and its surroundings, and because the surrounding sky is comparatively dark, the sunlit Moon is perceived as a bright object. The edges of the full moon seem as bright as the centre, with no limb darkening, due to the reflective properties of lunar soil, which reflects more light back towards the Sun than in other directions. The Moon does appear larger when close to the horizon, but this is a purely psychological effect, known as the Moon illusion, first described in the 7th century BC. The full moon subtends an arc of about 0.52 ° ( on average ) in the sky, roughly the same apparent size as the Sun ( see § Eclipses ). The highest altitude of the Moon in the sky varies with the lunar phase and the season of the year. The full moon is highest during winter. The 18.61 - year nodes cycle also has an influence : when the ascending node of the lunar orbit is in the vernal equinox, the lunar declination can go as far as 28 ° each month. This means the Moon can go overhead at latitudes up to 28 ° from the equator, instead of only 18 °. The orientation of the Moon 's crescent also depends on the latitude of the observation site : close to the equator, an observer can see a smile - shaped crescent moon. The Moon is visible for two weeks every 27.3 days at the North and South Pole. The Moon 's light is used by zooplankton in the Arctic when the sun is below the horizon for months on end. 14 November 2016 supermoon was 356,511 kilometres ( 221,526 mi ) away from the center of Earth, the closest occurrence since 26 January 1948. It will not be closer until 25 November 2034. The distance between the Moon and Earth varies from around 356,400 km ( 221,500 mi ) to 406,700 km ( 252,700 mi ) at perigees ( closest ) and apogees ( farthest ), respectively. On 14 November 2016, it was closer to Earth when at full phase than it has been since 1948, 14 % closer than its farthest position in apogee. Reported as a `` super moon '', this closest point coincides within an hour of a full moon, and it was 30 % more luminous than when at its greatest distance due to its angular diameter being 14 % greater, because 1.14 2 ≈ 1.30 ( displaystyle scriptstyle 1.14 ^ ( 2 ) approx 1.30 ). At lower levels, the human perception of reduced brightness as a percentage is provided by the following formula : perceived reduction % = 100 × actual reduction % 100 ( displaystyle ( \text ( perceived reduction ) ) % = 100 \times ( sqrt ( ( \text ( actual reduction ) ) % over 100 ) ) ) When the actual reduction is 1.00 / 1.30, or about 0.770, the perceived reduction is about 0.877, or 1.00 / 1.14. This gives a maximum perceived increase of 14 % between apogee and perigee moons of the same phase. There has been historical controversy over whether features on the Moon 's surface change over time. Today, many of these claims are thought to be illusory, resulting from observation under different lighting conditions, poor astronomical seeing, or inadequate drawings. However, outgassing does occasionally occur, and could be responsible for a minor percentage of the reported lunar transient phenomena. Recently, it has been suggested that a roughly 3 km ( 1.9 mi ) diameter region of the lunar surface was modified by a gas release event about a million years ago. The Moon 's appearance, like that of the Sun, can be affected by Earth 's atmosphere : common effects are a 22 ° halo ring formed when the Moon 's light is refracted through the ice crystals of high cirrostratus cloud, and smaller coronal rings when the Moon is seen through thin clouds. The monthly changes of angle between the direction of illumination by the Sun and viewing from Earth, and the phases of the Moon that result as viewed from the northern hemisphere. Earth -- Moon distance is not to scale. The illuminated area of the visible sphere ( degree of illumination ) is given by ( 1 − cos ⁡ e ) / 2 = sin 2 ⁡ ( e / 2 ) ( displaystyle ( 1 - cos e ) / 2 = sin ^ ( 2 ) ( e / 2 ) ), where e ( displaystyle e ) is the elongation ( i.e., the angle between Moon, the observer ( on Earth ) and the Sun ). Tidal effects Main articles : Tidal force, Tidal acceleration, Tide, and Theory of tides The libration of the Moon over a single lunar month. Also visible is the slight variation in the Moon 's visual size from Earth. The gravitational attraction that masses have for one another decreases inversely with the square of the distance of those masses from each other. As a result, the slightly greater attraction that the Moon has for the side of Earth closest to the Moon, as compared to the part of the Earth opposite the Moon, results in tidal forces. Tidal forces affect both the Earth 's crust and oceans. The most obvious effect of tidal forces is to cause two bulges in the Earth 's oceans, one on the side facing the Moon and the other on the side opposite. This results in elevated sea levels called ocean tides. As the Earth spins on its axis, one of the ocean bulges ( high tide ) is held in place `` under '' the Moon, while another such tide is opposite. As a result, there are two high tides, and two low tides in about 24 hours. Since the Moon is orbiting the Earth in the same direction of the Earth 's rotation, the high tides occur about every 12 hours and 25 minutes ; the 25 minutes is due to the Moon 's time to orbit the Earth. The Sun has the same tidal effect on the Earth, but its forces of attraction are only 40 % that of the Moon 's ; the Sun 's and Moon 's interplay is responsible for spring and neap tides. If the Earth were a water world ( one with no continents ) it would produce a tide of only one meter, and that tide would be very predictable, but the ocean tides are greatly modified by other effects : the frictional coupling of water to Earth 's rotation through the ocean floors, the inertia of water 's movement, ocean basins that grow shallower near land, the sloshing of water between different ocean basins. As a result, the timing of the tides at most points on the Earth is a product of observations that are explained, incidentally, by theory. While gravitation causes acceleration and movement of the Earth 's fluid oceans, gravitational coupling between the Moon and Earth 's solid body is mostly elastic and plastic. The result is a further tidal effect of the Moon on the Earth that causes a bulge of the solid portion of the Earth nearest the Moon that acts as a torque in opposition to the Earth 's rotation. This `` drains '' angular momentum and rotational kinetic energy from Earth 's spin, slowing the Earth 's rotation. That angular momentum, lost from the Earth, is transferred to the Moon in a process ( confusingly known as tidal acceleration ), which lifts the Moon into a higher orbit and results in its lower orbital speed about the Earth. Thus the distance between Earth and Moon is increasing, and the Earth 's spin is slowing in reaction. Measurements from laser reflectors left during the Apollo missions ( lunar ranging experiments ) have found that the Moon 's distance increases by 38 mm ( 1.5 in ) per year ( roughly the rate at which human fingernails grow ). Atomic clocks also show that Earth 's day lengthens by about 15 microseconds every year, slowly increasing the rate at which UTC is adjusted by leap seconds. Left to run its course, this tidal drag would continue until the spin of Earth and the orbital period of the Moon matched, creating mutual tidal locking between the two. As a result, the Moon would be suspended in the sky over one meridian, as is already currently the case with Pluto and its moon Charon. However, the Sun will become a red giant engulfing the Earth - Moon system long before this occurrence. In a like manner, the lunar surface experiences tides of around 10 cm ( 4 in ) amplitude over 27 days, with two components : a fixed one due to Earth, because they are in synchronous rotation, and a varying component from the Sun. The Earth - induced component arises from libration, a result of the Moon 's orbital eccentricity ( if the Moon 's orbit were perfectly circular, there would only be solar tides ). Libration also changes the angle from which the Moon is seen, allowing a total of about 59 % of its surface to be seen from Earth over time. The cumulative effects of stress built up by these tidal forces produces moonquakes. Moonquakes are much less common and weaker than are earthquakes, although moon quakes can last for up to an hour -- a significantly longer time than terrestrial quakes -- because of the absence of water to damp out the seismic vibrations. The existence of moonquakes was an unexpected discovery from seismometers placed on the Moon by Apollo astronauts from 1969 through 1972. Eclipses Main articles : Solar eclipse, Lunar eclipse, and Eclipse cycle From Earth, the Moon and the Sun appear the same size, as seen in the 1999 solar eclipse ( left ), whereas from the STEREO - B spacecraft in an Earth - trailing orbit, the Moon appears much smaller than the Sun ( right ). Eclipses can only occur when the Sun, Earth, and Moon are all in a straight line ( termed `` syzygy '' ). Solar eclipses occur at new moon, when the Moon is between the Sun and Earth. In contrast, lunar eclipses occur at full moon, when Earth is between the Sun and Moon. The apparent size of the Moon is roughly the same as that of the Sun, with both being viewed at close to one - half a degree wide. The Sun is much larger than the Moon but it is the precise vastly greater distance that gives it the same apparent size as the much closer and much smaller Moon from the perspective of Earth. The variations in apparent size, due to the non-circular orbits, are nearly the same as well, though occurring in different cycles. This makes possible both total ( with the Moon appearing larger than the Sun ) and annular ( with the Moon appearing smaller than the Sun ) solar eclipses. In a total eclipse, the Moon completely covers the disc of the Sun and the solar corona becomes visible to the naked eye. Because the distance between the Moon and Earth is very slowly increasing over time, the angular diameter of the Moon is decreasing. Also, as it evolves toward becoming a red giant, the size of the Sun, and its apparent diameter in the sky, are slowly increasing. The combination of these two changes means that hundreds of millions of years ago, the Moon would always completely cover the Sun on solar eclipses, and no annular eclipses were possible. Likewise, hundreds of millions of years in the future, the Moon will no longer cover the Sun completely, and total solar eclipses will not occur. Because the Moon 's orbit around Earth is inclined by about 5.145 ° ( 5 ° 9 ' ) to the orbit of Earth around the Sun, eclipses do not occur at every full and new moon. For an eclipse to occur, the Moon must be near the intersection of the two orbital planes. The periodicity and recurrence of eclipses of the Sun by the Moon, and of the Moon by Earth, is described by the saros, which has a period of approximately 18 years. Because the Moon is continuously blocking our view of a half - degree - wide circular area of the sky, the related phenomenon of occultation occurs when a bright star or planet passes behind the Moon and is occulted : hidden from view. In this way, a solar eclipse is an occultation of the Sun. Because the Moon is comparatively close to Earth, occultations of individual stars are not visible everywhere on the planet, nor at the same time. Because of the precession of the lunar orbit, each year different stars are occulted. Observation and Exploration Ancient and medieval studies Main articles : Exploration of the Moon : Early history, Selenography, and Lunar theory Map of the Moon by Johannes Hevelius from his Selenographia ( 1647 ), the first map to include the libration zones A study of the Moon in Robert Hooke 's Micrographia, 1665 Understanding of the Moon 's cycles was an early development of astronomy : by the 5th century BC, Babylonian astronomers had recorded the 18 - year Saros cycle of lunar eclipses, and Indian astronomers had described the Moon 's monthly elongation. The Chinese astronomer Shi Shen ( fl. 4th century BC ) gave instructions for predicting solar and lunar eclipses. Later, the physical form of the Moon and the cause of moonlight became understood. The ancient Greek philosopher Anaxagoras ( d. 428 BC ) reasoned that the Sun and Moon were both giant spherical rocks, and that the latter reflected the light of the former. Although the Chinese of the Han Dynasty believed the Moon to be energy equated to qi, their ' radiating influence ' theory also recognized that the light of the Moon was merely a reflection of the Sun, and Jing Fang ( 78 -- 37 BC ) noted the sphericity of the Moon. In the 2nd century AD, Lucian wrote the novel A True Story, in which the heroes travel to the Moon and meet its inhabitants. In 499 AD, the Indian astronomer Aryabhata mentioned in his Aryabhatiya that reflected sunlight is the cause of the shining of the Moon. The astronomer and physicist Alhazen ( 965 -- 1039 ) found that sunlight was not reflected from the Moon like a mirror, but that light was emitted from every part of the Moon 's sunlit surface in all directions. Shen Kuo ( 1031 -- 1095 ) of the Song dynasty created an allegory equating the waxing and waning of the Moon to a round ball of reflective silver that, when doused with white powder and viewed from the side, would appear to be a crescent. Galileo 's sketches of the Moon from Sidereus Nuncius In Aristotle 's ( 384 -- 322 BC ) description of the universe, the Moon marked the boundary between the spheres of the mutable elements ( earth, water, air and fire ), and the imperishable stars of aether, an influential philosophy that would dominate for centuries. However, in the 2nd century BC, Seleucus of Seleucia correctly theorized that tides were due to the attraction of the Moon, and that their height depends on the Moon 's position relative to the Sun. In the same century, Aristarchus computed the size and distance of the Moon from Earth, obtaining a value of about twenty times the radius of Earth for the distance. These figures were greatly improved by Ptolemy ( 90 -- 168 AD ) : his values of a mean distance of 59 times Earth 's radius and a diameter of 0.292 Earth diameters were close to the correct values of about 60 and 0.273 respectively. Archimedes ( 287 -- 212 BC ) designed a planetarium that could calculate the motions of the Moon and other objects in the Solar System. During the Middle Ages, before the invention of the telescope, the Moon was increasingly recognised as a sphere, though many believed that it was `` perfectly smooth ''. In 1609, Galileo Galilei drew one of the first telescopic drawings of the Moon in his book Sidereus Nuncius and noted that it was not smooth but had mountains and craters. Telescopic mapping of the Moon followed : later in the 17th century, the efforts of Giovanni Battista Riccioli and Francesco Maria Grimaldi led to the system of naming of lunar features in use today. The more exact 1834 -- 36 Mappa Selenographica of Wilhelm Beer and Johann Heinrich Mädler, and their associated 1837 book Der Mond, the first trigonometrically accurate study of lunar features, included the heights of more than a thousand mountains, and introduced the study of the Moon at accuracies possible in earthly geography. Lunar craters, first noted by Galileo, were thought to be volcanic until the 1870s proposal of Richard Proctor that they were formed by collisions. This view gained support in 1892 from the experimentation of geologist Grove Karl Gilbert, and from comparative studies from 1920 to the 1940s, leading to the development of lunar stratigraphy, which by the 1950s was becoming a new and growing branch of astrogeology. By spacecraft See also : Robotic exploration of the Moon, List of proposed missions to the Moon, Colonization of the Moon, and List of artificial objects on the Moon 20th century Soviet missions Main articles : Luna program and Lunokhod programme Luna 2, the first human - made object to reach the surface of the Moon ( left ) and Soviet Moon rover Lunokhod 1 The Cold War - inspired Space Race between the Soviet Union and the U.S. led to an acceleration of interest in exploration of the Moon. Once launchers had the necessary capabilities, these nations sent unmanned probes on both flyby and impact / lander missions. Spacecraft from the Soviet Union 's Luna program were the first to accomplish a number of goals : following three unnamed, failed missions in 1958, the first human - made object to escape Earth 's gravity and pass near the Moon was Luna 1 ; the first human - made object to impact the lunar surface was Luna 2, and the first photographs of the normally occluded far side of the Moon were made by Luna 3, all in 1959. The first spacecraft to perform a successful lunar soft landing was Luna 9 and the first unmanned vehicle to orbit the Moon was Luna 10, both in 1966. Rock and soil samples were brought back to Earth by three Luna sample return missions ( Luna 16 in 1970, Luna 20 in 1972, and Luna 24 in 1976 ), which returned 0.3 kg total. Two pioneering robotic rovers landed on the Moon in 1970 and 1973 as a part of Soviet Lunokhod programme. Luna 24 was the last Soviet / Russian mission to the Moon. United States missions Main articles : Apollo program and Moon landing Earthrise ( Apollo 8, 1968 ) Moon rock ( Apollo 17, 1972 ) During the late 1950s at the height of the Cold War, the United States Army conducted a classified feasibility study that proposed the construction of a manned military outpost on the Moon called Project Horizon with the potential to conduct a wide range of missions from scientific research to nuclear Earth bombardment. The study included the possibility of conducting a lunar - based nuclear test. The Air Force, which at the time was in competition with the Army for a leading role in the space program, developed its own similar plan called Lunex. However, both these proposals were ultimately passed over as the space program was largely transferred from the military to the civilian agency NASA. Following President John F. Kennedy 's 1961 commitment to a manned moon landing before the end of the decade, the United States, under NASA leadership, launched a series of unmanned probes to develop an understanding of the lunar surface in preparation for manned missions : the Jet Propulsion Laboratory 's Ranger program produced the first close - up pictures ; the Lunar Orbiter program produced maps of the entire Moon ; the Surveyor program landed its first spacecraft four months after Luna 9. The manned Apollo program was developed in parallel ; after a series of unmanned and manned tests of the Apollo spacecraft in Earth orbit, and spurred on by a potential Soviet lunar flight, in 1968 Apollo 8 made the first manned mission to lunar orbit. The subsequent landing of the first humans on the Moon in 1969 is seen by many as the culmination of the Space Race. Neil Armstrong working at the lunar module `` That 's one small step... '' Problems playing this file ? See media help. Neil Armstrong became the first person to walk on the Moon as the commander of the American mission Apollo 11 by first setting foot on the Moon at 02 : 56 UTC on 21 July 1969. An estimated 500 million people worldwide watched the transmission by the Apollo TV camera, the largest television audience for a live broadcast at that time. The Apollo missions 11 to 17 ( except Apollo 13, which aborted its planned lunar landing ) returned 380.05 kilograms ( 837.87 lb ) of lunar rock and soil in 2,196 separate samples. The American Moon landing and return was enabled by considerable technological advances in the early 1960s, in domains such as ablation chemistry, software engineering and atmospheric re-entry technology, and by highly competent management of the enormous technical undertaking. Scientific instrument packages were installed on the lunar surface during all the Apollo landings. Long - lived instrument stations, including heat flow probes, seismometers, and magnetometers, were installed at the Apollo 12, 14, 15, 16, and 17 landing sites. Direct transmission of data to Earth concluded in late 1977 due to budgetary considerations, but as the stations ' lunar laser ranging corner - cube retroreflector arrays are passive instruments, they are still being used. Ranging to the stations is routinely performed from Earth - based stations with an accuracy of a few centimetres, and data from this experiment are being used to place constraints on the size of the lunar core. 1980s -- 2000 An artificially coloured mosaic constructed from a series of 53 images taken through three spectral filters by Galileo ' s imaging system as the spacecraft flew over the northern regions of the Moon on 7 December 1992. After the first Moon race there were years of near quietude but starting in the 1990s, many more countries have become involved in direct exploration of the Moon. In 1990, Japan became the third country to place a spacecraft into lunar orbit with its Hiten spacecraft. The spacecraft released a smaller probe, Hagoromo, in lunar orbit, but the transmitter failed, preventing further scientific use of the mission. In 1994, the U.S. sent the joint Defense Department / NASA spacecraft Clementine to lunar orbit. This mission obtained the first near - global topographic map of the Moon, and the first global multispectral images of the lunar surface. This was followed in 1998 by the Lunar Prospector mission, whose instruments indicated the presence of excess hydrogen at the lunar poles, which is likely to have been caused by the presence of water ice in the upper few meters of the regolith within permanently shadowed craters. India, Japan, China, the United States, and the European Space Agency each sent lunar orbiters, and especially ISRO 's Chandrayaan - 1 has contributed to confirming the discovery of lunar water ice in permanently shadowed craters at the poles and bound into the lunar regolith. The post-Apollo era has also seen two rover missions : the final Soviet Lunokhod mission in 1973, and China 's ongoing Chang'e 3 mission, which deployed its Yutu rover on 14 December 2013. The Moon remains, under the Outer Space Treaty, free to all nations to explore for peaceful purposes. 21st century Artistic representation of a future Moon colony The European spacecraft SMART - 1, the second ion - propelled spacecraft, was in lunar orbit from 15 November 2004 until its lunar impact on 3 September 2006, and made the first detailed survey of chemical elements on the lunar surface. The ambitious Chinese Lunar Exploration Program began with Chang'e 1, which successfully orbited the Moon from 5 November 2007 until its controlled lunar impact on 1 March 2009. It obtained a full image map of the Moon. Chang'e 2, beginning in October 2010, reached the Moon more quickly, mapped the Moon at a higher resolution over an eight - month period, then left lunar orbit for an extended stay at the Earth -- Sun L2 Lagrangian point, before finally performing a flyby of asteroid 4179 Toutatis on 13 December 2012, and then heading off into deep space. On 14 December 2013, Chang'e 3 landed a lunar lander onto the Moon 's surface, which in turn deployed a lunar rover, named Yutu ( Chinese : 玉兔 ; literally `` Jade Rabbit '' ). This was the first lunar soft landing since Luna 24 in 1976, and the first lunar rover mission since Lunokhod 2 in 1973. China intends to launch another rover mission ( Chang'e 4 ) before 2020, followed by a sample return mission ( Chang'e 5 ) soon after. Between 4 October 2007 and 10 June 2009, the Japan Aerospace Exploration Agency 's Kaguya ( Selene ) mission, a lunar orbiter fitted with a high - definition video camera, and two small radio - transmitter satellites, obtained lunar geophysics data and took the first high - definition movies from beyond Earth orbit. India 's first lunar mission, Chandrayaan I, orbited from 8 November 2008 until loss of contact on 27 August 2009, creating a high resolution chemical, mineralogical and photo - geological map of the lunar surface, and confirming the presence of water molecules in lunar soil. The Indian Space Research Organisation planned to launch Chandrayaan II in 2013, which would have included a Russian robotic lunar rover. However, the failure of Russia 's Fobos - Grunt mission has delayed this project. Copernicus 's central peaks as observed by the LRO, 2012 The Ina formation, 2009 The U.S. co-launched the Lunar Reconnaissance Orbiter ( LRO ) and the LCROSS impactor and follow - up observation orbiter on 18 June 2009 ; LCROSS completed its mission by making a planned and widely observed impact in the crater Cabeus on 9 October 2009, whereas LRO is currently in operation, obtaining precise lunar altimetry and high - resolution imagery. In November 2011, the LRO passed over the large and bright Aristarchus crater. NASA released photos of the crater on 25 December 2011. Two NASA GRAIL spacecraft began orbiting the Moon around 1 January 2012, on a mission to learn more about the Moon 's internal structure. NASA 's LADEE probe, designed to study the lunar exosphere, achieved orbit on 6 October 2013. Upcoming lunar missions include Russia 's Luna - Glob : an unmanned lander with a set of seismometers, and an orbiter based on its failed Martian Fobos - Grunt mission. Privately funded lunar exploration has been promoted by the Google Lunar X Prize, announced 13 September 2007, which offers US $20 million to anyone who can land a robotic rover on the Moon and meet other specified criteria. Shackleton Energy Company is building a program to establish operations on the south pole of the Moon to harvest water and supply their Propellant Depots. NASA began to plan to resume manned missions following the call by U.S. President George W. Bush on 14 January 2004 for a manned mission to the Moon by 2019 and the construction of a lunar base by 2024. The Constellation program was funded and construction and testing begun on a manned spacecraft and launch vehicle, and design studies for a lunar base. However, that program has been cancelled in favor of a manned asteroid landing by 2025 and a manned Mars orbit by 2035. India has also expressed its hope to send a manned mission to the Moon by 2020. Planned commercial missions In 2007, the X Prize Foundation together with Google launched the Google Lunar X Prize to encourage commercial endeavors to the Moon. A prize of $20 million will be awarded to the first private venture to get to the moon with a robotic lander by the end of March 2018, with additional prizes worth $10 million for further milestones. As of August 2016, 16 teams are participating in the competition. In August 2016, the US government granted permission to US - based start - up Moon Express to land on the Moon. This marked the first time that a private enterprise was given the right to do so. The decision is regarded as a precedent helping to define regulatory standards for deep - space commercial activity in the future, as thus far companies ' operation had been restricted to being on or around Earth. Astronomy from the Moon A false - color image of Earth in ultraviolet light taken from the surface of the Moon on the Apollo 16 mission. The day - side reflects a lot of UV light from the Sun, but the night - side shows faint bands of UV emission from the aurora caused by charged particles. For many years, the Moon has been recognized as an excellent site for telescopes. It is relatively nearby ; astronomical seeing is not a concern ; certain craters near the poles are permanently dark and cold, and thus especially useful for infrared telescopes ; and radio telescopes on the far side would be shielded from the radio chatter of Earth. The lunar soil, although it poses a problem for any moving parts of telescopes, can be mixed with carbon nanotubes and epoxies and employed in the construction of mirrors up to 50 meters in diameter. A lunar zenith telescope can be made cheaply with ionic liquid. In April 1972, the Apollo 16 mission recorded various astronomical photos and spectra in ultraviolet with the Far Ultraviolet Camera / Spectrograph. Legal status Main article : Space law Although Luna landers scattered pennants of the Soviet Union on the Moon, and U.S. flags were symbolically planted at their landing sites by the Apollo astronauts, no nation claims ownership of any part of the Moon 's surface. Russia and the U.S. are party to the 1967 Outer Space Treaty, which defines the Moon and all outer space as the `` province of all mankind ''. This treaty also restricts the use of the Moon to peaceful purposes, explicitly banning military installations and weapons of mass destruction. The 1979 Moon Agreement was created to restrict the exploitation of the Moon 's resources by any single nation, but as of 2014, it has been signed and ratified by only 16 nations, none of which engages in self - launched human space exploration or has plans to do so. Although several individuals have made claims to the Moon in whole or in part, none of these are considered credible. In culture Luna, the Moon, from a 1550 edition of Guido Bonatti 's Liber astronomiae See also : Moon in fiction Mythology Further information : Lunar deity, Selene, Luna ( goddess ), Man in the Moon, and Crescent Sun and Moon with faces ( 1493 woodcut ) A 5,000 - year - old rock carving at Knowth, Ireland, may represent the Moon, which would be the earliest depiction discovered. The contrast between the brighter highlands and the darker maria creates the patterns seen by different cultures as the Man in the Moon, the rabbit and the buffalo, among others. In many prehistoric and ancient cultures, the Moon was personified as a deity or other supernatural phenomenon, and astrological views of the Moon continue to be propagated today. In Proto - Indo - European religion, the moon was personified as the male god * Meh not. The ancient Sumerians believed that the moon was the god Nanna, who was the father of Inanna, the goddess of the planet Venus, and Utu, the god of the sun. Nanna was later known as Sîn, and was particularly associated with magic and sorcery. In Greco - Roman mythology, the Sun and the Moon are represented as male and female, respectively ( Helios / Sol and Selene / Luna ) ; this is a development unique to the eastern Mediterranean and traces of an earlier male moon god in the Greek tradition are preserved in the figure of Menelaus. In Mesopotamian iconography, the crescent was the primary symbol of Nanna - Sîn. In ancient Greek art, the Moon goddess Selene was represented wearing a crescent on her headgear in an arrangement reminiscent of horns. The star and crescent arrangement also goes back to the Bronze Age, representing either the Sun and Moon, or the Moon and planet Venus, in combination. It came to represent the goddess Artemis or Hecate, and via the patronage of Hecate came to be used as a symbol of Byzantium. An iconographic tradition of representing Sun and Moon with faces developed in the late medieval period. The splitting of the moon ( Arabic : انشقاق القمر ‎ ) is a miracle attributed to Muhammad. Calendar Further information : Lunar calendar, Lunisolar calendar, Metonic cycle, Blue moon, and Movable feast The Moon 's regular phases make it a very convenient timepiece, and the periods of its waxing and waning form the basis of many of the oldest calendars. Tally sticks, notched bones dating as far back as 20 -- 30,000 years ago, are believed by some to mark the phases of the Moon. The ~ 30 - day month is an approximation of the lunar cycle. The English noun month and its cognates in other Germanic languages stem from Proto - Germanic * mǣnṓth -, which is connected to the above - mentioned Proto - Germanic * mǣnōn, indicating the usage of a lunar calendar among the Germanic peoples ( Germanic calendar ) prior to the adoption of a solar calendar. The PIE root of moon, * méh nōt, derives from the PIE verbal root * meh -, `` to measure '', `` indicat ( ing ) a functional conception of the moon, i.e. marker of the month '' ( cf. the English words measure and menstrual ), and echoing the Moon 's importance to many ancient cultures in measuring time ( see Latin mensis and Ancient Greek μείς ( meis ) or μήν ( mēn ), meaning `` month '' ). Most historical calendars are lunisolar. The 7th - century Islamic calendar is an exceptional example of a purely lunar calendar. Months are traditionally determined by the visual sighting of the hilal, or earliest crescent moon, over the horizon. `` Moonrise '', 1884, picture by Stanisław Masłowski ( National Museum, Kraków, Gallery of Sukiennice Museum ) Lunacy Further information : Lunar effect The Moon has long been associated with insanity and irrationality ; the words lunacy and lunatic ( popular shortening loony ) are derived from the Latin name for the Moon, Luna. Philosophers Aristotle and Pliny the Elder argued that the full moon induced insanity in susceptible individuals, believing that the brain, which is mostly water, must be affected by the Moon and its power over the tides, but the Moon 's gravity is too slight to affect any single person. Even today, people who believe in a lunar effect claim that admissions to psychiatric hospitals, traffic accidents, homicides or suicides increase during a full moon, but dozens of studies invalidate these claims. See also Solar System portal Moon portal Astronomy portal List of lunar features Former classification of planets Other moons of Earth 2006 RH 120 List of natural satellites Tourism on the Moon Timeline of the far future References Notes Jump up ^ Between 18.29 ° and 28.58 ° to Earth 's equator. Jump up ^ There are a number of near - Earth asteroids, including 3753 Cruithne, that are co-orbital with Earth : their orbits bring them close to Earth for periods of time but then alter in the long term ( Morais et al, 2002 ). These are quasi-satellites -- they are not moons as they do not orbit Earth. For more information, see Other moons of Earth. Jump up ^ The maximum value is given based on scaling of the brightness from the value of − 12.74 given for an equator to Moon - centre distance of 378 000 km in the NASA factsheet reference to the minimum Earth -- Moon distance given there, after the latter is corrected for Earth 's equatorial radius of 6 378 km, giving 350 600 km. The minimum value ( for a distant new moon ) is based on a similar scaling using the maximum Earth -- Moon distance of 407 000 km ( given in the factsheet ) and by calculating the brightness of the earthshine onto such a new moon. The brightness of the earthshine is ( Earth albedo × ( Earth radius / Radius of Moon 's orbit ) ) relative to the direct solar illumination that occurs for a full moon. ( Earth albedo = 0.367 ; Earth radius = ( polar radius × equatorial radius ) = 6 367 km. ) Jump up ^ The range of angular size values given are based on simple scaling of the following values given in the fact sheet reference : at an Earth - equator to Moon - centre distance of 378 000 km, the angular size is 1896 arcseconds. The same fact sheet gives extreme Earth -- Moon distances of 407 000 km and 357 000 km. For the maximum angular size, the minimum distance has to be corrected for Earth 's equatorial radius of 6 378 km, giving 350 600 km. Jump up ^ Lucey et al. ( 2006 ) give 10 particles cm by day and 10 particles cm by night. Along with equatorial surface temperatures of 390 K by day and 100 K by night, the ideal gas law yields the pressures given in the infobox ( rounded to the nearest order of magnitude ) : 10 Pa by day and 10 Pa by night. Jump up ^ This age is calculated from isotope dating of lunar zircons. Jump up ^ More accurately, the Moon 's mean sidereal period ( fixed star to fixed star ) is 27.321661 days ( 27 d 07 h 43 min 11.5 s ), and its mean tropical orbital period ( from equinox to equinox ) is 27.321582 days ( 27 d 07 h 43 min 04.7 s ) ( Explanatory Supplement to the Astronomical Ephemeris, 1961, at p. 107 ). Jump up ^ More accurately, the Moon 's mean synodic period ( between mean solar conjunctions ) is 29.530589 days ( 29 d 12 h 44 min 02.9 s ) ( Explanatory Supplement to the Astronomical Ephemeris, 1961, at p. 107 ). Jump up ^ There is no strong correlation between the sizes of planets and the sizes of their satellites. Larger planets tend to have more satellites, both large and small, than smaller planets. Jump up ^ With 27 % the diameter and 60 % the density of Earth, the Moon has 1.23 % of the mass of Earth. The moon Charon is larger relative to its primary Pluto, but Pluto is now considered to be a dwarf planet. Jump up ^ The Sun 's apparent magnitude is − 26.7, while the full moon 's apparent magnitude is − 12.7. Jump up ^ See graph in Sun # Life phases. At present, the diameter of the Sun is increasing at a rate of about five percent per billion years. This is very similar to the rate at which the apparent angular diameter of the Moon is decreasing as it recedes from Earth. Jump up ^ On average, the Moon covers an area of 0.21078 square degrees on the night sky. Citations ^ Jump up to : Wieczorek, Mark A. ; et al. ( 2006 ). `` The constitution and structure of the lunar interior ''. Reviews in Mineralogy and Geochemistry. 60 ( 1 ) : 221 -- 364. Bibcode : 2006RvMG... 60... 221W. doi : 10.2138 / rmg. 2006.60. 3. ^ Jump up to : Lang, Kenneth R. ( 2011 ), The Cambridge Guide to the Solar System Archived 1 January 2016 at the Wayback Machine., 2nd ed., Cambridge University Press. Jump up ^ Morais, M.H.M. ; Morbidelli, A. ( 2002 ). `` The Population of Near - Earth Asteroids in Coorbital Motion with the Earth ''. Icarus. 160 ( 1 ) : 1 -- 9. Bibcode : 2002Icar... 160... 1M. doi : 10.1006 / icar. 2002.6937. ^ Jump up to : Williams, Dr. David R. ( 2 February 2006 ). `` Moon Fact Sheet ''. NASA / National Space Science Data Center. Archived from the original on 23 March 2010. Retrieved 31 December 2008. Jump up ^ Smith, David E. ; Zuber, Maria T. ; Neumann, Gregory A. ; Lemoine, Frank G. ( 1 January 1997 ). `` Topography of the Moon from the Clementine lidar ''. Journal of Geophysical Research. 102 ( E1 ) : 1601. Bibcode : 1997JGR... 102.1591 S. doi : 10.1029 / 96JE02940. Jump up ^ Williams, James G. ; Newhall, XX ; Dickey, Jean O. ( 1996 ). `` Lunar moments, tides, orientation, and coordinate frames ''. Planetary and Space Science. 44 ( 10 ) : 1077 -- 1080. Bibcode : 1996P&SS... 44.1077 W. doi : 10.1016 / 0032 - 0633 ( 95 ) 00154 - 9. Jump up ^ Matthews, Grant ( 2008 ). `` Celestial body irradiance determination from an underfilled satellite radiometer : application to albedo and thermal emission measurements of the Moon using CERES ''. Applied Optics. 47 ( 27 ) : 4981 -- 93. Bibcode : 2008ApOpt... 47.4981 M. doi : 10.1364 / AO. 47.004981. PMID 18806861. Jump up ^ A.R. Vasavada ; D.A. Paige & S.E. Wood ( 1999 ). `` Near - Surface Temperatures on Mercury and the Moon and the Stability of Polar Ice Deposits ''. Icarus. 141 ( 2 ) : 179 -- 193. Bibcode : 1999Icar... 141... 179V. doi : 10.1006 / icar. 1999.6175. ^ Jump up to : Lucey, Paul ; Korotev, Randy L. ; et al. ( 2006 ). `` Understanding the lunar surface and space - Moon interactions ''. Reviews in Mineralogy and Geochemistry. 60 ( 1 ) : 83 -- 219. Bibcode : 2006RvMG... 60... 83L. doi : 10.2138 / rmg. 2006.60. 2. Jump up ^ `` How far away is the moon ? : : NASA Space Place ''. Archived from the original on 6 October 2016. Jump up ^ Scott, Elaine. Our Moon : New Discoveries About Earth 's Closest Companion. Houghton Mifflin Harcourt ( 2016 ) ISBN 9780544750586. page 7. Jump up ^ `` Naming Astronomical Objects : Spelling of Names ''. International Astronomical Union. Archived from the original on 16 December 2008. Retrieved 29 March 2010. Jump up ^ `` Gazetteer of Planetary Nomenclature : Planetary Nomenclature FAQ ''. USGS Astrogeology Research Program. Archived from the original on 27 May 2010. Retrieved 29 March 2010. Jump up ^ Barnhart, Robert K. ( 1995 ). The Barnhart Concise Dictionary of Etymology. USA : Harper Collins. p. 487. ISBN 978 - 0 - 06 - 270084 - 1. Jump up ^ Oxford English Dictionary, 2nd ed. `` luna '', Oxford University Press ( Oxford ), 2009. Jump up ^ `` Oxford English Dictionary : lunar, a. and n ''. Oxford English Dictionary : Second Edition 1989. Oxford University Press. Retrieved 23 March 2010. Jump up ^ σελήνη. Liddell, Henry George ; Scott, Robert ; A Greek -- English Lexicon at the Perseus Project. Jump up ^ Imke Pannen ( 2010 ). When the Bad Bleeds : Mantic Elements in English Renaissance Revenge Tragedy. V&R unipress GmbH. pp. 96 --. ISBN 978 - 3 - 89971 - 640 - 5. Archived from the original on 4 September 2016. Jump up ^ Barboni, M. ; Boehnke, P. ; Keller, C.B. ; Kohl, I.E. ; Schoene, B. ; Young, E.D. ; McKeegan, K.D. ( 2017 ). `` Early formation of the Moon 4.51 billion years ago ''. Science Advances. 3 ( 1 ) : e1602365. Bibcode : 2017SciA... 3E2365B. doi : 10.1126 / sciadv. 1602365. Jump up ^ Binder, A.B. ( 1974 ). `` On the origin of the Moon by rotational fission ''. The Moon. 11 ( 2 ) : 53 -- 76. Bibcode : 1974Moon... 11... 53B. doi : 10.1007 / BF01877794. ^ Jump up to : Stroud, Rick ( 2009 ). The Book of the Moon. Walken and Company. pp. 24 -- 27. ISBN 978 - 0 - 8027 - 1734 - 4. Jump up ^ Mitler, H.E. ( 1975 ). `` Formation of an iron - poor moon by partial capture, or : Yet another exotic theory of lunar origin ''. Icarus. 24 ( 2 ) : 256 -- 268. Bibcode : 1975Icar... 24... 256M. doi : 10.1016 / 0019 - 1035 ( 75 ) 90102 - 5. Jump up ^ Stevenson, D.J. ( 1987 ). `` Origin of the moon -- The collision hypothesis ''. Annual Review of Earth and Planetary Sciences. 15 ( 1 ) : 271 -- 315. Bibcode : 1987AREPS... 15... 271S. doi : 10.1146 / annurev. ea. 15.050187. 001415. Jump up ^ Taylor, G. Jeffrey ( 31 December 1998 ). `` Origin of the Earth and Moon ''. Planetary Science Research Discoveries. Hawai'i Institute of Geophysics and Planetology. Archived from the original on 10 June 2010. Retrieved 7 April 2010. Jump up ^ `` Asteroids Bear Scars of Moon 's Violent Formation ''. 16 April 2015. Archived from the original on 8 October 2016. Jump up ^ Dana Mackenzie ( 21 July 2003 ). The Big Splat, or How Our Moon Came to Be. John Wiley & Sons. pp. 166 -- 168. ISBN 978 - 0 - 471 - 48073 - 0. Archived from the original on 1 January 2016. Jump up ^ Canup, R. ; Asphaug, E. ( 2001 ). `` Origin of the Moon in a giant impact near the end of Earth 's formation ''. Nature. 412 ( 6848 ) : 708 -- 712. Bibcode : 2001Natur. 412... 708C. doi : 10.1038 / 35089010. PMID 11507633. Jump up ^ `` Earth - Asteroid Collision Formed Moon Later Than Thought ''. National Geographic. 28 October 2010. Archived from the original on 18 April 2009. Retrieved 7 May 2012. Jump up ^ `` 2008 Pellas - Ryder Award for Mathieu Touboul '' ( PDF ). Meteoritical Society. 2008. Jump up ^ Touboul, M. ; Kleine, T. ; Bourdon, B. ; Palme, H. ; Wieler, R. ( 2007 ). `` Late formation and prolonged differentiation of the Moon inferred from W isotopes in lunar metals ''. Nature. 450 ( 7173 ) : 1206 -- 9. Bibcode : 2007Natur. 450.1206 T. doi : 10.1038 / nature06428. PMID 18097403. Jump up ^ `` Flying Oceans of Magma Help Demystify the Moon 's Creation ''. National Geographic. 8 April 2015. Archived from the original on 9 April 2015. Jump up ^ Pahlevan, Kaveh ; Stevenson, David J. ( 2007 ). `` Equilibration in the aftermath of the lunar - forming giant impact ''. Earth and Planetary Science Letters. 262 ( 3 -- 4 ) : 438 -- 449. arXiv : 1012.5323. Bibcode : 2007E&PSL. 262... 438P. doi : 10.1016 / j. epsl. 2007.07. 055. Jump up ^ Nield, Ted ( 2009 ). `` Moonwalk ( summary of meeting at Meteoritical Society 's 72nd Annual Meeting, Nancy, France ) ''. Geoscientist. Vol. 19. p. 8. Archived from the original on 27 September 2012. ^ Jump up to : Warren, P.H. ( 1985 ). `` The magma ocean concept and lunar evolution ''. Annual Review of Earth and Planetary Sciences. 13 ( 1 ) : 201 -- 240. Bibcode : 1985AREPS... 13... 201W. doi : 10.1146 / annurev. ea. 13.050185. 001221. Jump up ^ Tonks, W. Brian ; Melosh, H. Jay ( 1993 ). `` Magma ocean formation due to giant impacts ''. Journal of Geophysical Research. 98 ( E3 ) : 5319 -- 5333. Bibcode : 1993JGR... 98.5319 T. doi : 10.1029 / 92JE02726. Jump up ^ Daniel Clery ( 11 October 2013 ). `` Impact Theory Gets Whacked ''. Science. 342 ( 6155 ) : 183 -- 185. Bibcode : 2013Sci... 342... 183C. doi : 10.1126 / science. 342.6155. 183. PMID 24115419. Jump up ^ Wiechert, U. ; et al. ( October 2001 ). `` Oxygen Isotopes and the Moon - Forming Giant Impact ''. Science. 294 ( 12 ) : 345 -- 348. Bibcode : 2001Sci... 294... 345W. doi : 10.1126 / science. 1063037. PMID 11598294. Archived from the original on 20 April 2009. Retrieved 5 July 2009. Jump up ^ Pahlevan, Kaveh ; Stevenson, David ( October 2007 ). `` Equilibration in the Aftermath of the Lunar - forming Giant Impact ''. EPSL. 262 ( 3 -- 4 ) : 438 -- 449. arXiv : 1012.5323. Bibcode : 2007E&PSL. 262... 438P. doi : 10.1016 / j. epsl. 2007.07. 055. Jump up ^ `` Titanium Paternity Test Says Earth is the Moon 's Only Parent ( University of Chicago ) ''. Astrobio.net. Retrieved 3 October 2013. Jump up ^ Taylor, Stuart Ross ( 1975 ). Lunar science : A post-Apollo view. Pergamon Press. p. 64. Bibcode : 1975lspa. book... T. Jump up ^ Brown, D. ; Anderson, J. ( 6 January 2011 ). `` NASA Research Team Reveals Moon Has Earth - Like Core ''. NASA. NASA. Archived from the original on 15 March 2012. Jump up ^ Weber, R.C. ; Lin, P. - Y. ; Garnero, E.J. ; Williams, Q. ; Lognonne, P. ( 21 January 2011 ). `` Seismic Detection of the Lunar Core '' ( PDF ). Science. 331 ( 6015 ) : 309 -- 312. Bibcode : 2011Sci... 331... 309W. doi : 10.1126 / science. 1199375. PMID 21212323. Archived ( PDF ) from the original on 15 October 2015. Jump up ^ Nemchin, A. ; Timms, N. ; Pidgeon, R. ; Geisler, T. ; Reddy, S. ; Meyer, C. ( 2009 ). `` Timing of crystallization of the lunar magma ocean constrained by the oldest zircon ''. Nature Geoscience. 2 ( 2 ) : 133 -- 136. Bibcode : 2009NatGe... 2... 133N. doi : 10.1038 / ngeo417. ^ Jump up to : Shearer, Charles K. ; et al. ( 2006 ). `` Thermal and magmatic evolution of the Moon ''. Reviews in Mineralogy and Geochemistry. 60 ( 1 ) : 365 -- 518. Bibcode : 2006RvMG... 60... 365S. doi : 10.2138 / rmg. 2006.60. 4. Jump up ^ Schubert, J. ( 2004 ). `` Interior composition, structure, and dynamics of the Galilean satellites. ''. In F. Bagenal ; et al. Jupiter : The Planet, Satellites, and Magnetosphere. Cambridge University Press. pp. 281 -- 306. ISBN 978 - 0 - 521 - 81808 - 7. Jump up ^ Williams, J.G. ; Turyshev, S.G. ; Boggs, D.H. ; Ratcliff, J.T. ( 2006 ). `` Lunar laser ranging science : Gravitational physics and lunar interior and geodesy ''. Advances in Space Research. 37 ( 1 ) : 67 -- 71. arXiv : gr - qc / 0412049. Bibcode : 2006AdSpR... 37... 67W. doi : 10.1016 / j. asr. 2005.05. 013. Jump up ^ Spudis, Paul D. ; Cook, A. ; Robinson, M. ; Bussey, B. ; Fessler, B. ( January 1998 ). `` Topography of the South Polar Region from Clementine Stereo Imaging ''. Workshop on New Views of the Moon : Integrated Remotely Sensed, Geophysical, and Sample Datasets : 69. Bibcode : 1998nvmi. conf... 69S. ^ Jump up to : Spudis, Paul D. ; Reisse, Robert A. ; Gillis, Jeffrey J. ( 1994 ). `` Ancient Multiring Basins on the Moon Revealed by Clementine Laser Altimetry ''. Science. 266 ( 5192 ) : 1848 -- 1851. Bibcode : 1994Sci... 266.1848 S. doi : 10.1126 / science. 266.5192. 1848. PMID 17737079. Jump up ^ Pieters, C.M. ; Tompkins, S. ; Head, J.W. ; Hess, P.C. ( 1997 ). `` Mineralogy of the Mafic Anomaly in the South Pole ‐ Aitken Basin : Implications for excavation of the lunar mantle ''. Geophysical Research Letters. 24 ( 15 ) : 1903 -- 1906. Bibcode : 1997GeoRL... 24.1903 P. doi : 10.1029 / 97GL01718. Jump up ^ Taylor, G.J. ( 17 July 1998 ). `` The Biggest Hole in the Solar System ''. Planetary Science Research Discoveries. Hawai'i Institute of Geophysics and Planetology. Archived from the original on 20 August 2007. Retrieved 12 April 2007. Jump up ^ Schultz, P.H. ( March 1997 ). `` Forming the south - pole Aitken basin -- The extreme games ''. Conference Paper, 28th Annual Lunar and Planetary Science Conference. 28 : 1259. Bibcode : 1997LPI... 28.1259 S. Jump up ^ `` NASA 's LRO Reveals ' Incredible Shrinking Moon ' ''. NASA. 19 August 2010. Archived from the original on 21 August 2010. Jump up ^ Wlasuk, Peter ( 2000 ). Observing the Moon. Springer. p. 19. ISBN 978 - 1 - 85233 - 193 - 1. Jump up ^ Norman, M. ( 21 April 2004 ). `` The Oldest Moon Rocks ''. Planetary Science Research Discoveries. Hawai'i Institute of Geophysics and Planetology. Archived from the original on 18 April 2007. Retrieved 12 April 2007. Jump up ^ Varricchio, L. ( 2006 ). Inconstant Moon. Xlibris Books. ISBN 978 - 1 - 59926 - 393 - 9. Jump up ^ Head, L.W.J.W. ( 2003 ). `` Lunar Gruithuisen and Mairan domes : Rheology and mode of emplacement ''. Journal of Geophysical Research. 108 ( E2 ) : 5012. Bibcode : 2003JGRE... 108.5012 W. doi : 10.1029 / 2002JE001909. Archived from the original on 12 March 2007. Retrieved 12 April 2007. ^ Jump up to : Spudis, P.D. ( 2004 ). `` Moon ''. World Book Online Reference Center, NASA. Archived from the original on 3 July 2013. Retrieved 12 April 2007. Jump up ^ Gillis, J.J. ; Spudis, P.D. ( 1996 ). `` The Composition and Geologic Setting of Lunar Far Side Maria ''. Lunar and Planetary Science. 27 : 413. Bibcode : 1996LPI... 27... 413G. Jump up ^ Lawrence, D.J., et al. ( 11 August 1998 ). `` Global Elemental Maps of the Moon : The Lunar Prospector Gamma - Ray Spectrometer ''. Science. 281 ( 5382 ) : 1484 -- 1489. Bibcode : 1998Sci... 281.1484 L. doi : 10.1126 / science. 281.5382. 1484. PMID 9727970. Archived from the original on 16 May 2009. Retrieved 29 August 2009. Jump up ^ Taylor, G.J. ( 31 August 2000 ). `` A New Moon for the Twenty - First Century ''. Planetary Science Research Discoveries. Hawai'i Institute of Geophysics and Planetology. Archived from the original on 15 March 2012. Retrieved 12 April 2007. ^ Jump up to : Papike, J. ; Ryder, G. ; Shearer, C. ( 1998 ). `` Lunar Samples ''. Reviews in Mineralogy and Geochemistry. 36 : 5.1 -- 5.234. ^ Jump up to : Hiesinger, H. ; Head, J.W. ; Wolf, U. ; Jaumanm, R. ; Neukum, G. ( 2003 ). `` Ages and stratigraphy of mare basalts in Oceanus Procellarum, Mare Numbium, Mare Cognitum, and Mare Insularum ''. Journal of Geophysical Research. 108 ( E7 ) : 1029. Bibcode : 2003JGRE... 108.5065 H. doi : 10.1029 / 2002JE001985. ^ Jump up to : Phil Berardelli ( 9 November 2006 ). `` Long Live the Moon ! ''. Science. Archived from the original on 18 October 2014. Jump up ^ Jason Major ( 14 October 2014 ). `` Volcanoes Erupted ' Recently ' on the Moon ''. Discovery News. Archived from the original on 16 October 2014. Jump up ^ `` NASA Mission Finds Widespread Evidence of Young Lunar Volcanism ''. NASA. 12 October 2014. Archived from the original on 3 January 2015. Jump up ^ Eric Hand ( 12 October 2014 ). `` Recent volcanic eruptions on the moon ''. Science. Archived from the original on 14 October 2014. Jump up ^ Braden, S.E. ; Stopar, J.D. ; Robinson, M.S. ; Lawrence, S.J. ; van der Bogert, C.H. ; Hiesinger, H. doi = 10.1038 / ngeo2252 ( 2014 ). `` Evidence for basaltic volcanism on the Moon within the past 100 million years ''. Nature Geoscience. 7 ( 11 ) : 787 -- 791. Bibcode : 2014NatGe... 7... 787B. doi : 10.1038 / ngeo2252. Jump up ^ Srivastava, N. ; Gupta, R.P. ( 2013 ). `` Young viscous flows in the Lowell crater of Orientale basin, Moon : Impact melts or volcanic eruptions ? ''. Planetary and Space Science. 87 : 37 -- 45. Bibcode : 2013P&SS... 87... 37S. doi : 10.1016 / j. pss. 2013.09. 001. Jump up ^ Gupta, R.P. ; Srivastava, N. ; Tiwari, R.K. ( 2014 ). `` Evidences of relatively new volcanic flows on the Moon ''. Current Science. 107 ( 3 ) : 454 -- 460. Jump up ^ Whitten, J. ; et al. ( 2011 ). `` Lunar mare deposits associated with the Orientale impact basin : New insights into mineralogy, history, mode of emplacement, and relation to Orientale Basin evolution from Moon Mineralogy Mapper ( M3 ) data from Chandrayaan - 1 ''. Journal of Geophysical Research. 116 : E00G09. Bibcode : 2011JGRE... 116.0 G09W. doi : 10.1029 / 2010JE003736. Jump up ^ Cho, Y. ; et al. ( 2012 ). `` Young mare volcanism in the Orientale region contemporary with the Procellarum KREEP Terrane ( PKT ) volcanism peak period 2 b.y. ago ''. Geophysical Research Letters. 39 ( 11 ) : L11203. Bibcode : 2012GeoRL... 3911203C. doi : 10.1029 / 2012GL051838. Jump up ^ Munsell, K. ( 4 December 2006 ). `` Majestic Mountains ''. Solar System Exploration. NASA. Archived from the original on 17 September 2008. Retrieved 12 April 2007. Jump up ^ Richard Lovett. `` Early Earth may have had two moons : Nature News ''. Nature. Archived from the original on 3 November 2012. Retrieved 1 November 2012. Jump up ^ `` Was our two - faced moon in a small collision ? ''. Theconversation.edu.au. Archived from the original on 30 January 2013. Retrieved 1 November 2012. Jump up ^ Melosh, H.J. ( 1989 ). Impact cratering : A geologic process. Oxford University Press. ISBN 978 - 0 - 19 - 504284 - 9. Jump up ^ `` Moon Facts ''. SMART - 1. European Space Agency. 2010. Retrieved 12 May 2010. ^ Jump up to : Wilhelms, Don ( 1987 ). `` Relative Ages ''. Geologic History of the Moon ( PDF ). U.S. Geological Survey. Archived ( PDF ) from the original on 11 June 2010. Jump up ^ Hartmann, William K. ; Quantin, Cathy ; Mangold, Nicolas ( 2007 ). `` Possible long - term decline in impact rates : 2. Lunar impact - melt data regarding impact history ''. Icarus. 186 ( 1 ) : 11 -- 23. Bibcode : 2007Icar... 186... 11H. doi : 10.1016 / j. icarus. 2006.09. 009. Jump up ^ `` The Smell of Moondust ''. NASA. 30 January 2006. Archived from the original on 8 March 2010. Retrieved 15 March 2010. Jump up ^ Heiken, G. ( 1991 ). Vaniman, D. ; French, B., eds. Lunar Sourcebook, a user 's guide to the Moon. New York : Cambridge University Press. p. 736. ISBN 978 - 0 - 521 - 33444 - 0. Jump up ^ Rasmussen, K.L. ; Warren, P.H. ( 1985 ). `` Megaregolith thickness, heat flow, and the bulk composition of the Moon ''. Nature. 313 ( 5998 ) : 121 -- 124. Bibcode : 1985Natur. 313... 121R. doi : 10.1038 / 313121a0. Jump up ^ Boyle, Rebecca. `` The moon has hundreds more craters than we thought ''. Archived from the original on 13 October 2016. Jump up ^ Speyerer, Emerson J. ; Povilaitis, Reinhold Z. ; Robinson, Mark S. ; Thomas, Peter C. ; Wagner, Robert V. ( 13 October 2016 ). `` Quantifying crater production and regolith overturn on the Moon with temporal imaging ''. Nature. 538 ( 7624 ) : 215 -- 218. Bibcode : 2016Natur. 538... 215S. doi : 10.1038 / nature19829. PMID 27734864 -- via www.nature.com. Jump up ^ Margot, J.L. ; Campbell, D.B. ; Jurgens, R.F. ; Slade, M.A. ( 4 June 1999 ). `` Topography of the Lunar Poles from Radar Interferometry : A Survey of Cold Trap Locations '' ( PDF ). Science. 284 ( 5420 ) : 1658 -- 1660. Bibcode : 1999Sci... 284.1658 M. doi : 10.1126 / science. 284.5420. 1658. PMID 10356393. Jump up ^ Ward, William R. ( 1 August 1975 ). `` Past Orientation of the Lunar Spin Axis ''. Science. 189 ( 4200 ) : 377 -- 379. Bibcode : 1975Sci... 189... 377W. doi : 10.1126 / science. 189.4200. 377. PMID 17840827. ^ Jump up to : Martel, L.M.V. ( 4 June 2003 ). `` The Moon 's Dark, Icy Poles ''. Planetary Science Research Discoveries. Hawai'i Institute of Geophysics and Planetology. Archived from the original on 15 March 2012. Retrieved 12 April 2007. Jump up ^ Seedhouse, Erik ( 2009 ). Lunar Outpost : The Challenges of Establishing a Human Settlement on the Moon. Springer - Praxis Books in Space Exploration. Germany : Springer Praxis. p. 136. ISBN 978 - 0 - 387 - 09746 - 6. Jump up ^ Coulter, Dauna ( 18 March 2010 ). `` The Multiplying Mystery of Moonwater ''. NASA. Archived from the original on 16 May 2016. Retrieved 28 March 2010. Jump up ^ Spudis, P. ( 6 November 2006 ). `` Ice on the Moon ''. The Space Review. Archived from the original on 22 February 2007. Retrieved 12 April 2007. Jump up ^ Feldman, W.C. ; S. Maurice ; A.B. Binder ; B.L. Barraclough ; R.C. Elphic ; D.J. Lawrence ( 1998 ). `` Fluxes of Fast and Epithermal Neutrons from Lunar Prospector : Evidence for Water Ice at the Lunar Poles ''. Science. 281 ( 5382 ) : 1496 -- 1500. Bibcode : 1998Sci... 281.1496 F. doi : 10.1126 / science. 281.5382. 1496. PMID 9727973. Jump up ^ Saal, Alberto E. ; Hauri, Erik H. ; Cascio, Mauro L. ; van Orman, James A. ; Rutherford, Malcolm C. ; Cooper, Reid F. ( 2008 ). `` Volatile content of lunar volcanic glasses and the presence of water in the Moon 's interior ''. Nature. 454 ( 7201 ) : 192 -- 195. Bibcode : 2008Natur. 454... 192S. doi : 10.1038 / nature07047. PMID 18615079. Jump up ^ Pieters, C.M. ; Goswami, J.N. ; Clark, R.N. ; Annadurai, M. ; Boardman, J. ; Buratti, B. ; Combe, J. - P. ; Dyar, M.D. ; Green, R. ; Head, J.W. ; Hibbitts, C. ; Hicks, M. ; Isaacson, P. ; Klima, R. ; Kramer, G. ; Kumar, S. ; Livo, E. ; Lundeen, S. ; Malaret, E. ; McCord, T. ; Mustard, J. ; Nettles, J. ; Petro, N. ; Runyon, C. ; Staid, M. ; Sunshine, J. ; Taylor, L.A. ; Tompkins, S. ; Varanasi, P. ( 2009 ). `` Character and Spatial Distribution of OH / H2O on the Surface of the Moon Seen by M3 on Chandrayaan - 1 ''. Science. 326 ( 5952 ) : 568 -- 72. Bibcode : 2009Sci... 326... 568P. doi : 10.1126 / science. 1178658. PMID 19779151. Jump up ^ Lakdawalla, Emily ( 13 November 2009 ). `` LCROSS Lunar Impactor Mission : `` Yes, We Found Water ! '' ``. The Planetary Society. Archived from the original on 22 January 2010. Retrieved 13 April 2010. Jump up ^ Colaprete, A. ; Ennico, K. ; Wooden, D. ; Shirley, M. ; Heldmann, J. ; Marshall, W. ; Sollitt, L. ; Asphaug, E. ; Korycansky, D. ; Schultz, P. ; Hermalyn, B. ; Galal, K. ; Bart, G.D. ; Goldstein, D. ; Summy, D. ( 1 -- 5 March 2010 ). `` Water and More : An Overview of LCROSS Impact Results ''. 41st Lunar and Planetary Science Conference. 41 ( 1533 ) : 2335. Bibcode : 2010LPI... 41.2335 C. Jump up ^ Colaprete, Anthony ; Schultz, Peter ; Heldmann, Jennifer ; Wooden, Diane ; Shirley, Mark ; Ennico, Kimberly ; Hermalyn, Brendan ; Marshall, William ; Ricco, Antonio ; Elphic, Richard C. ; Goldstein, David ; Summy, Dustin ; Bart, Gwendolyn D. ; Asphaug, Erik ; Korycansky, Don ; Landis, David ; Sollitt, Luke ( 22 October 2010 ). `` Detection of Water in the LCROSS Ejecta Plume ''. Science. 330 ( 6003 ) : 463 -- 468. Bibcode : 2010Sci... 330... 463C. doi : 10.1126 / science. 1186986. PMID 20966242. Jump up ^ Hauri, Erik ; Thomas Weinreich ; Albert E. Saal ; Malcolm C. Rutherford ; James A. Van Orman ( 26 May 2011 ). `` High Pre-Eruptive Water Contents Preserved in Lunar Melt Inclusions ''. Science Express. 10 ( 1126 ) : 213 -- 215. Bibcode : 2011Sci... 333... 213H. doi : 10.1126 / science. 1204626. Jump up ^ Muller, P. ; Sjogren, W. ( 1968 ). `` Mascons : lunar mass concentrations ''. Science. 161 ( 3842 ) : 680 -- 684. Bibcode : 1968Sci... 161... 680M. doi : 10.1126 / science. 161.3842. 680. PMID 17801458. Jump up ^ Richard A. Kerr ( 12 April 2013 ). `` The Mystery of Our Moon 's Gravitational Bumps Solved ? ''. Science. 340 ( 6129 ) : 138 -- 139. doi : 10.1126 / science. 340.6129. 138 - a. PMID 23580504. Jump up ^ Konopliv, A. ; Asmar, S. ; Carranza, E. ; Sjogren, W. ; Yuan, D. ( 2001 ). `` Recent gravity models as a result of the Lunar Prospector mission '' ( PDF ). Icarus. 50 ( 1 ) : 1 -- 18. Bibcode : 2001Icar... 150... 1K. doi : 10.1006 / icar. 2000.6573. Archived from the original ( PDF ) on 13 November 2004. Jump up ^ Garrick - Bethell, Ian ; Weiss, iBenjamin P. ; Shuster, David L. ; Buz, Jennifer ( 2009 ). `` Early Lunar Magnetism ''. Science. 323 ( 5912 ) : 356 -- 359. Bibcode : 2009Sci... 323... 356G. doi : 10.1126 / science. 1166804. PMID 19150839. Jump up ^ `` Magnetometer / Electron Reflectometer Results ''. Lunar Prospector ( NASA ). 2001. Archived from the original on 27 May 2010. Retrieved 17 March 2010. Jump up ^ Hood, L.L. ; Huang, Z. ( 1991 ). `` Formation of magnetic anomalies antipodal to lunar impact basins : Two - dimensional model calculations ''. Journal of Geophysical Research. 96 ( B6 ) : 9837 -- 9846. Bibcode : 1991JGR... 96.9837 H. doi : 10.1029 / 91JB00308. Jump up ^ `` Moon Storms ''. NASA. 27 September 2013. Archived from the original on 12 September 2013. Retrieved 3 October 2013. Jump up ^ Culler, Jessica ( 16 June 2015 ). `` LADEE - Lunar Atmosphere Dust and Environment Explorer ''. Archived from the original on 8 April 2015. Jump up ^ Globus, Ruth ( 1977 ). `` Chapter 5, Appendix J : Impact Upon Lunar Atmosphere ''. In Richard D. Johnson & Charles Holbrow. Space Settlements : A Design Study. NASA. Archived from the original on 31 May 2010. Retrieved 17 March 2010. Jump up ^ Crotts, Arlin P.S. ( 2008 ). `` Lunar Outgassing, Transient Phenomena and The Return to The Moon, I : Existing Data '' ( PDF ). The Astrophysical Journal. 687 : 692 -- 705. arXiv : 0706.3949. Bibcode : 2008ApJ... 687... 692C. doi : 10.1086 / 591634. Archived ( PDF ) from the original on 20 February 2009. Jump up ^ Steigerwald, William ( 17 August 2015 ). `` NASA 's LADEE Spacecraft Finds Neon in Lunar Atmosphere ''. NASA. Retrieved 18 August 2015. ^ Jump up to : Stern, S.A. ( 1999 ). `` The Lunar atmosphere : History, status, current problems, and context ''. Reviews in Geophysical. 37 ( 4 ) : 453 -- 491. Bibcode : 1999RvGeo... 37... 453S. doi : 10.1029 / 1999RG900005. Jump up ^ Lawson, S. ; Feldman, W. ; Lawrence, D. ; Moore, K. ; Elphic, R. ; Belian, R. ( 2005 ). `` Recent outgassing from the lunar surface : the Lunar Prospector alpha particle spectrometer ''. Journal of Geophysical Research. 110 ( E9 ) : 1029. Bibcode : 2005JGRE... 11009009L. doi : 10.1029 / 2005JE002433. Jump up ^ R. Sridharan ; S.M. Ahmed ; Tirtha Pratim Dasa ; P. Sreelathaa ; P. Pradeepkumara ; Neha Naika ; Gogulapati Supriya ( 2010 ). `` ' Direct ' evidence for water ( H2O ) in the sunlit lunar ambience from CHACE on MIP of Chandrayaan I ''. Planetary and Space Science. 58 ( 6 ) : 947 -- 950. Bibcode : 2010P&SS... 58... 947S. doi : 10.1016 / j. pss. 2010.02. 013. Jump up ^ Drake, Nadia ; 17, National Geographic PUBLISHED June. `` Lopsided Cloud of Dust Discovered Around the Moon ''. National Geographic News. Archived from the original on 19 June 2015. Retrieved 20 June 2015. Jump up ^ Horányi, M. ; Szalay, J.R. ; Kempf, S. ; Schmidt, J. ; Grün, E. ; Srama, R. ; Sternovsky, Z. ( 18 June 2015 ). `` A permanent, asymmetric dust cloud around the Moon ''. Nature. 522 ( 7556 ) : 324 -- 326. Bibcode : 2015Natur. 522... 324H. doi : 10.1038 / nature14479. PMID 26085272. Jump up ^ http://time.com/4974580/nasa-moon-had-atmosphere-volcanoes Jump up ^ Hamilton, Calvin J. ; Hamilton, Rosanna L., The Moon, Views of the Solar System Archived 4 February 2016 at the Wayback Machine., 1995 -- 2011. ^ Jump up to : Amos, Jonathan ( 16 December 2009 ). `` ' Coldest place ' found on the Moon ''. BBC News. Retrieved 20 March 2010. Jump up ^ `` Diviner News ''. UCLA. 17 September 2009. Archived from the original on 7 March 2010. Retrieved 17 March 2010. Jump up ^ Rocheleau, Jake. `` Temperature on the Moon -- Surface Temperature of the Moon -- PlanetFacts.org ''. Archived from the original on 27 May 2015. Jump up ^ Global influences of the 18.61 year nodal cycle and 8.85 year cycle of lunar perigee on high tidal levels, U. of Western Australia Jump up ^ VV Belet︠s︡kiĭ ( 2001 ). Essays on the Motion of Celestial Bodies. Birkhäuser. p. 183. ISBN 978 - 3 - 7643 - 5866 - 2. Jump up ^ `` Space Topics : Pluto and Charon ''. The Planetary Society. Archived from the original on 15 March 2012. Retrieved 6 April 2010. Jump up ^ `` Planet Definition Questions & Answers Sheet '' ( DOC ). International Astronomical Union. 2006. Archived from the original on 29 April 2014. Retrieved 24 March 2010. Jump up ^ Alexander, M.E. ( 1973 ). `` The Weak Friction Approximation and Tidal Evolution in Close Binary Systems ''. Astrophysics and Space Science. 23 ( 2 ) : 459 -- 508. Bibcode : 1973Ap&SS... 23... 459A. doi : 10.1007 / BF00645172. Jump up ^ Phil Plait. `` Dark Side of the Moon ''. Bad Astronomy : Misconceptions. Archived from the original on 12 April 2010. Retrieved 15 February 2010. Jump up ^ `` Moon used to spin ' on different axis ' ''. BBC. Archived from the original on 23 March 2016. Retrieved 23 March 2016. Jump up ^ Luciuk, Mike. `` How Bright is the Moon ? ''. Amateur Astronomers. Archived from the original on 12 March 2010. Retrieved 16 March 2010. Jump up ^ Hershenson, Maurice ( 1989 ). The Moon illusion. Routledge. p. 5. ISBN 978 - 0 - 8058 - 0121 - 7. Jump up ^ Spekkens, K. ( 18 October 2002 ). `` Is the Moon seen as a crescent ( and not a `` boat '' ) all over the world ? ``. Curious About Astronomy. Archived from the original on 16 October 2015. Retrieved 28 September 2015. Jump up ^ `` Moonlight helps plankton escape predators during Arctic winters ''. New Scientist. 16 January 2016. Archived from the original on 30 January 2016. Jump up ^ `` '' Super Moon '' exceptional. Brightest moon in the sky of Normandy, Monday, November 14 - The Siver Times ``. Archived from the original on 14 November 2016. Jump up ^ `` Moongazers Delight -- Biggest Supermoon In Decades Looms Large Sunday Night ''. 10 November 2016. Archived from the original on 14 November 2016. Jump up ^ `` Supermoon November 2016 ''. Space.com. 13 November 2016. Archived from the original on 14 November 2016. Retrieved 14 November 2016. Jump up ^ Tony Phillips ( 16 March 2011 ). `` Super Full Moon ''. NASA. Archived from the original on 7 May 2012. Retrieved 19 March 2011. Jump up ^ Richard K. De Atley ( 18 March 2011 ). `` Full moon tonight is as close as it gets ''. The Press - Enterprise. Archived from the original on 22 March 2011. Retrieved 19 March 2011. Jump up ^ `` ' Super moon ' to reach closest point for almost 20 years ''. The Guardian. 19 March 2011. Archived from the original on 25 December 2013. Retrieved 19 March 2011. Jump up ^ Georgia State University, Dept. of Physics ( Astronomy ). `` Perceived Brightness ''. Brightnes and Night / Day Sensitivity. Georgia State University. Archived from the original on 21 February 2014. Retrieved 25 January 2014. Jump up ^ Lutron. `` Measured light vs. perceived light '' ( PDF ). From IES Lighting Handbook 2000, 27 - 4. Lutron. Archived ( PDF ) from the original on 5 February 2013. Retrieved 25 January 2014. Jump up ^ Walker, John ( May 1997 ). `` Inconstant Moon ''. Earth and Moon Viewer. Fourth paragraph of `` How Bright the Moonlight '' : Fourmilab. Archived from the original on 14 December 2013. Retrieved 23 January 2014. 14 % (... ) due to the logarithmic response of the human eye. Jump up ^ Taylor, G.J. ( 8 November 2006 ). `` Recent Gas Escape from the Moon ''. Planetary Science Research Discoveries. Hawai'i Institute of Geophysics and Planetology. Archived from the original on 4 March 2007. Retrieved 4 April 2007. Jump up ^ Schultz, P.H. ; Staid, M.I. ; Pieters, C.M. ( 2006 ). `` Lunar activity from recent gas release ''. Nature. 444 ( 7116 ) : 184 -- 186. Bibcode : 2006Natur. 444... 184S. doi : 10.1038 / nature05303. PMID 17093445. Jump up ^ `` 22 Degree Halo : a ring of light 22 degrees from the sun or moon ''. Department of Atmospheric Sciences, University of Illinois at Urbana - Champaign. Retrieved 13 April 2010. ^ Jump up to : Lambeck, K. ( 1977 ). `` Tidal Dissipation in the Oceans : Astronomical, Geophysical and Oceanographic Consequences ''. Philosophical Transactions of the Royal Society A. 287 ( 1347 ) : 545 -- 594. Bibcode : 1977RSPTA. 287... 545L. doi : 10.1098 / rsta. 1977.0159. Jump up ^ Le Provost, C. ; Bennett, A.F. ; Cartwright, D.E. ( 1995 ). `` Ocean Tides for and from TOPEX / POSEIDON ''. Science. 267 ( 5198 ) : 639 -- 42. Bibcode : 1995Sci... 267... 639L. doi : 10.1126 / science. 267.5198. 639. PMID 17745840. ^ Jump up to : Touma, Jihad ; Wisdom, Jack ( 1994 ). `` Evolution of the Earth - Moon system ''. The Astronomical Journal. 108 ( 5 ) : 1943 -- 1961. Bibcode : 1994AJ... 108.1943 T. doi : 10.1086 / 117209. Jump up ^ Chapront, J. ; Chapront - Touzé, M. ; Francou, G. ( 2002 ). `` A new determination of lunar orbital parameters, precession constant and tidal acceleration from LLR measurements ''. Astronomy and Astrophysics. 387 ( 2 ) : 700 -- 709. Bibcode : 2002A&A... 387... 700C. doi : 10.1051 / 0004 - 6361 : 20020420. Jump up ^ `` Why the Moon is getting further away from Earth ''. BBC News. 1 February 2011. Archived from the original on 25 September 2015. Retrieved 18 September 2015. Jump up ^ Ray, R. ( 15 May 2001 ). `` Ocean Tides and the Earth 's Rotation ''. IERS Special Bureau for Tides. Archived from the original on 27 March 2010. Retrieved 17 March 2010. Jump up ^ Murray, C.D. ; Dermott, Stanley F. ( 1999 ). Solar System Dynamics. Cambridge University Press. p. 184. ISBN 978 - 0 - 521 - 57295 - 8. Jump up ^ Dickinson, Terence ( 1993 ). From the Big Bang to Planet X. Camden East, Ontario : Camden House. pp. 79 -- 81. ISBN 978 - 0 - 921820 - 71 - 0. Jump up ^ Latham, Gary ; Ewing, Maurice ; Dorman, James ; Lammlein, David ; Press, Frank ; Toksőz, Naft ; Sutton, George ; Duennebier, Fred ; Nakamura, Yosio ( 1972 ). `` Moonquakes and lunar tectonism ''. Earth, Moon, and Planets. 4 ( 3 -- 4 ) : 373 -- 382. Bibcode : 1972Moon... 4... 373L. doi : 10.1007 / BF00562004. Jump up ^ Phillips, Tony ( 12 March 2007 ). `` Stereo Eclipse ''. Science@NASA. Archived from the original on 10 June 2008. Retrieved 17 March 2010. Jump up ^ Espenak, F. ( 2000 ). `` Solar Eclipses for Beginners ''. MrEclip ) ). Retrieved 17 March 2010. Jump up ^ Walker, John ( 10 July 2004 ). `` Moon near Perigee, Earth near Aphelion ''. Fourmilab. Archived from the original on 8 December 2013. Retrieved 25 December 2013. Jump up ^ Thieman, J. ; Keating, S. ( 2 May 2006 ). `` Eclipse 99, Frequently Asked Questions ''. NASA. Archived from the original on 11 February 2007. Retrieved 12 April 2007. Jump up ^ Espenak, F. `` Saros Cycle ''. NASA. Archived from the original on 24 May 2012. Retrieved 17 March 2010. Jump up ^ Guthrie, D.V. ( 1947 ). `` The Square Degree as a Unit of Celestial Area ''. Popular Astronomy. Vol. 55. pp. 200 -- 203. Bibcode : 1947PA... 55... 200G. Jump up ^ `` Total Lunar Occultations ''. Royal Astronomical Society of New Zealand. Archived from the original on 23 February 2010. Retrieved 17 March 2010. Jump up ^ Aaboe, A. ; Britton, J.P. ; Henderson,, J.A. ; Neugebauer, Otto ; Sachs, A.J. ( 1991 ). `` Saros Cycle Dates and Related Babylonian Astronomical Texts ''. Transactions of the American Philosophical Society. American Philosophical Society. 81 ( 6 ) : 1 -- 75. doi : 10.2307 / 1006543. JSTOR 1006543. One comprises what we have called `` Saros Cycle Texts '', which give the months of eclipse possibilities arranged in consistent cycles of 223 months ( or 18 years ). Jump up ^ Sarma, K.V. ( 2008 ). `` Astronomy in India ''. In Helaine Selin. Encyclopaedia of the History of Science, Technology, and Medicine in Non-Western Cultures ( 2 ed. ). Springer. pp. 317 -- 321. ISBN 978 - 1 - 4020 - 4559 - 2. Jump up ^ Needham 1986, p. 411. Jump up ^ O'Connor, J.J. ; Robertson, E.F. ( February 1999 ). `` Anaxagoras of Clazomenae ''. University of St Andrews. Archived from the original on 15 March 2012. Retrieved 12 April 2007. Jump up ^ Needham 1986, p. 227. Jump up ^ Needham 1986, p. 413 -- 414. Jump up ^ Robertson, E.F. ( November 2000 ). `` Aryabhata the Elder ''. Scotland : School of Mathematics and Statistics, University of St Andrews. Archived from the original on 11 July 2015. Retrieved 15 April 2010. Jump up ^ A.I. Sabra ( 2008 ). `` Ibn Al - Haytham, Abū ʿAlī Al - Ḥasan Ibn Al - Ḥasan ''. Dictionary of Scientific Biography. Detroit : Charles Scribner 's Sons. pp. 189 -- 210, at 195. Jump up ^ Needham 1986, p. 415 -- 416. Jump up ^ Lewis, C.S. ( 1964 ). The Discarded Image. Cambridge : Cambridge University Press. p. 108. ISBN 978 - 0 - 521 - 47735 - 2. Jump up ^ van der Waerden, Bartel Leendert ( 1987 ). `` The Heliocentric System in Greek, Persian and Hindu Astronomy ''. Annals of the New York Academy of Sciences. 500 : 1 -- 569. Bibcode : 1987NYASA. 500... 1A. doi : 10.1111 / j. 1749 - 6632.1987. tb37193. x. PMID 3296915. Jump up ^ Evans, James ( 1998 ). The History and Practice of Ancient Astronomy. Oxford & New York : Oxford University Press. pp. 71, 386. ISBN 978 - 0 - 19 - 509539 - 5. Jump up ^ `` Discovering How Greeks Computed in 100 B.C ''. The New York Times. 31 July 2008. Archived from the original on 4 December 2013. Retrieved 9 March 2014. Jump up ^ Van Helden, A. ( 1995 ). `` The Moon ''. Galileo Project. Archived from the original on 23 June 2004. Retrieved 12 April 2007. Jump up ^ Consolmagno, Guy J. ( 1996 ). `` Astronomy, Science Fiction and Popular Culture : 1277 to 2001 ( And beyond ) ''. Leonardo. The MIT Press. 29 ( 2 ) : 128. doi : 10.2307 / 1576348. JSTOR 1576348. Jump up ^ Hall, R. Cargill ( 1977 ). `` Appendix A : LUNAR THEORY BEFORE 1964 ''. NASA History Series. LUNAR IMPACT : A History of Project Ranger. Washington, D.C. : Scientific and Technical Information Office, NASA. Archived from the original on 10 April 2010. Retrieved 13 April 2010. Jump up ^ Zak, Anatoly ( 2009 ). `` Russia 's unmanned missions toward the Moon ''. Archived from the original on 14 April 2010. Retrieved 20 April 2010. Jump up ^ `` Rocks and Soils from the Moon ''. NASA. Archived from the original on 27 May 2010. Retrieved 6 April 2010. ^ Jump up to : `` Soldiers, Spies and the Moon : Secret U.S. and Soviet Plans from the 1950s and 1960s ''. The National Security Archive. National Security Archive. Archived from the original on 19 December 2016. Retrieved 1 May 2017. Jump up ^ Brumfield, Ben ( 25 July 2014 ). `` U.S. reveals secret plans for ' 60s moon base ''. CNN. Archived from the original on 27 July 2014. Retrieved 26 July 2014. Jump up ^ Teitel, Amy ( 11 November 2013 ). `` LUNEX : Another way to the Moon ''. Popular Science. Archived from the original on 16 October 2015. ^ Jump up to : Logsdon, John ( 2010 ). John F. Kennedy and the Race to the Moon. Palgrave Macmillan. ISBN 978 - 0 - 230 - 11010 - 6. Jump up ^ Coren, M. ( 26 July 2004 ). `` ' Giant leap ' opens world of possibility ''. CNN. Archived from the original on 16 March 2012. Retrieved 16 March 2010. Jump up ^ `` Record of Lunar Events, 24 July 1969 ''. Apollo 11 30th anniversary. NASA. Archived from the original on 8 April 2010. Retrieved 13 April 2010. Jump up ^ `` Manned Space Chronology : Apollo_11 ''. Spaceline.org. Archived from the original on 14 February 2008. Retrieved 6 February 2008. Jump up ^ `` Apollo Anniversary : Moon Landing `` Inspired World '' ``. National Geographic. Archived from the original on 9 February 2008. Retrieved 6 February 2008. Jump up ^ Orloff, Richard W. ( September 2004 ) ( First published 2000 ). `` Extravehicular Activity ''. Apollo by the Numbers : A Statistical Reference. NASA History Division, Office of Policy and Plans. The NASA History Series. Washington, D.C. : NASA. ISBN 0 - 16 - 050631 - X. LCCN 00061677. NASA SP - 2000 - 4029. Archived from the original on 6 June 2013. Retrieved 1 August 2013. Jump up ^ Launius, Roger D. ( July 1999 ). `` The Legacy of Project Apollo ''. NASA History Office ) ). Archived from the original on 8 April 2010. Retrieved 13 April 2010. Jump up ^ SP - 287 What Made Apollo a Success ? A series of eight articles reprinted by permission from the March 1970 issue of Astronautics & Aeronautics, a publication of the American Institute of Aeronautics and Astronautics. Washington, D.C. : Scientific and Technical Information Office, National Aeronautics and Space Administration. 1971. Jump up ^ `` NASA news release 77 - 47 page 242 '' ( PDF ) ( Press release ). 1 September 1977. Archived ( PDF ) from the original on 26 June 2011. Retrieved 16 March 2010. Jump up ^ Appleton, James ; Radley, Charles ; Deans, John ; Harvey, Simon ; Burt, Paul ; Haxell, Michael ; Adams, Roy ; Spooner N. ; Brieske, Wayne ( 1977 ). `` OASI Newsletters Archive ''. NASA Turns A Deaf Ear To The Moon. Archived from the original on 10 December 2007. Retrieved 29 August 2007. Jump up ^ Dickey, J. ; et al. ( 1994 ). `` Lunar laser ranging : a continuing legacy of the Apollo program ''. Science. 265 ( 5171 ) : 482 -- 490. Bibcode : 1994Sci... 265... 482D. doi : 10.1126 / science. 265.5171. 482. PMID 17781305. Jump up ^ `` Hiten - Hagomoro ''. NASA. Archived from the original on 14 June 2011. Retrieved 29 March 2010. Jump up ^ `` Clementine information ''. NASA. 1994. Archived from the original on 25 September 2010. Retrieved 29 March 2010. Jump up ^ `` Lunar Prospector : Neutron Spectrometer ''. NASA. 2001. Archived from the original on 27 May 2010. Retrieved 29 March 2010. Jump up ^ `` SMART - 1 factsheet ''. European Space Agency. 26 February 2007. Archived from the original on 23 March 2010. Retrieved 29 March 2010. Jump up ^ `` China 's first lunar probe ends mission ''. Xinhua. 1 March 2009. Archived from the original on 4 March 2009. Retrieved 29 March 2010. Jump up ^ Leonard David ( 17 March 2015 ). `` China Outlines New Rockets, Space Station and Moon Plans ''. Space.com. Archived from the original on 1 July 2016. Retrieved 29 June 2016. Jump up ^ `` KAGUYA Mission Profile ''. JAXA. Archived from the original on 28 March 2010. Retrieved 13 April 2010. Jump up ^ `` KAGUYA ( SELENE ) World 's First Image Taking of the Moon by HDTV ''. Japan Aerospace Exploration Agency ( JAXA ) and Japan Broadcasting Corporation ( NHK ). 7 November 2007. Archived from the original on 16 March 2010. Retrieved 13 April 2010. Jump up ^ `` Mission Sequence ''. Indian Space Research Organisation. 17 November 2008. Archived from the original on 6 July 2010. Retrieved 13 April 2010. Jump up ^ `` Indian Space Research Organisation : Future Program ''. Indian Space Research Organisation. Archived from the original on 25 November 2010. Retrieved 13 April 2010. Jump up ^ `` India and Russia Sign an Agreement on Chandrayaan - 2 ''. Indian Space Research Organisation. 14 November 2007. Archived from the original on 17 December 2007. Retrieved 13 April 2010. Jump up ^ `` Lunar CRater Observation and Sensing Satellite ( LCROSS ) : Strategy & Astronomer Observation Campaign ''. NASA. October 2009. Archived from the original on 15 March 2012. Retrieved 13 April 2010. Jump up ^ `` Giant moon crater revealed in spectacular up - close photos ''. MSNBC. Space.com. 6 January 2012. Archived from the original on 7 January 2012. Jump up ^ Chang, Alicia ( 26 December 2011 ). `` Twin probes to circle moon to study gravity field ''. CNS News. Associated Press. Retrieved 18 June 2017. Jump up ^ Covault, C. ( 4 June 2006 ). `` Russia Plans Ambitious Robotic Lunar Mission ''. Aviation Week. Archived from the original on 12 June 2006. Retrieved 12 April 2007. Jump up ^ `` Russia to send mission to Mars this year, Moon in three years ''. TV - Novosti. 25 February 2009. Archived from the original on 13 September 2010. Retrieved 13 April 2010. Jump up ^ `` About the Google Lunar X Prize ''. X-Prize Foundation. 2010. Archived from the original on 28 February 2010. Retrieved 24 March 2010. Jump up ^ Wall, Mike ( 14 January 2011 ). `` Mining the Moon 's Water : Q&A with Shackleton Energy 's Bill Stone ''. Space News. Jump up ^ `` President Bush Offers New Vision For NASA '' ( Press release ). NASA. 14 December 2004. Archived from the original on 10 May 2007. Retrieved 12 April 2007. Jump up ^ `` Constellation ''. NASA. Archived from the original on 12 April 2010. Retrieved 13 April 2010. Jump up ^ `` NASA Unveils Global Exploration Strategy and Lunar Architecture '' ( Press release ). NASA. 4 December 2006. Archived from the original on 23 August 2007. Retrieved 12 April 2007. Jump up ^ NASAtelevision ( 15 April 2010 ). `` President Obama Pledges Total Commitment to NASA ''. YouTube. Archived from the original on 28 April 2012. Retrieved 7 May 2012. Jump up ^ `` India 's Space Agency Proposes Manned Spaceflight Program ''. Space.com. 10 November 2006. Archived from the original on 15 March 2012. Retrieved 23 October 2008. Jump up ^ Chang, Kenneth ( 24 January 2017 ). `` For 5 Contest Finalists, a $20 Million Dash to the Moon ''. The New York Times. ISSN 0362 - 4331. Archived from the original on 15 July 2017. Retrieved 13 July 2017. Jump up ^ Mike Wall ( 16 August 2017 ), `` Deadline for Google Lunar X Prize Moon Race Extended Through March 2018 '', space.com, retrieved 25 September 2017 Jump up ^ McCarthy, Ciara ( 3 August 2016 ). `` US startup Moon Express approved to make 2017 lunar mission ''. The Guardian. ISSN 0261 - 3077. Archived from the original on 30 July 2017. Retrieved 13 July 2017. ^ Jump up to : `` Moon Express Approved for Private Lunar Landing in 2017, a Space First ''. Space.com. Archived from the original on 12 July 2017. Retrieved 13 July 2017. Jump up ^ `` NASA - Ultraviolet Waves ''. Science.hq.nasa.gov. 27 September 2013. Archived from the original on 17 October 2013. Retrieved 3 October 2013. Jump up ^ Takahashi, Yuki ( September 1999 ). `` Mission Design for Setting up an Optical Telescope on the Moon ''. California Institute of Technology. Archived from the original on 6 November 2015. Retrieved 27 March 2011. Jump up ^ Chandler, David ( 15 February 2008 ). `` MIT to lead development of new telescopes on moon ''. MIT News. Archived from the original on 4 March 2009. Retrieved 27 March 2011. Jump up ^ Naeye, Robert ( 6 April 2008 ). `` NASA Scientists Pioneer Method for Making Giant Lunar Telescopes ''. Goddard Space Flight Center. Archived from the original on 22 December 2010. Retrieved 27 March 2011. Jump up ^ Bell, Trudy ( 9 October 2008 ). `` Liquid Mirror Telescopes on the Moon ''. Science News. NASA. Archived from the original on 23 March 2011. Retrieved 27 March 2011. Jump up ^ `` Far Ultraviolet Camera / Spectrograph ''. Lpi.usra.edu. Archived from the original on 3 December 2013. Retrieved 3 October 2013. ^ Jump up to : `` Can any State claim a part of outer space as its own ? ''. United Nations Office for Outer Space Affairs. Archived from the original on 21 April 2010. Retrieved 28 March 2010. Jump up ^ `` How many States have signed and ratified the five international treaties governing outer space ? ''. United Nations Office for Outer Space Affairs. 1 January 2006. Archived from the original on 21 April 2010. Retrieved 28 March 2010. Jump up ^ `` Do the five international treaties regulate military activities in outer space ? ''. United Nations Office for Outer Space Affairs. Archived from the original on 21 April 2010. Retrieved 28 March 2010. Jump up ^ `` Agreement Governing the Activities of States on the Moon and Other Celestial Bodies ''. United Nations Office for Outer Space Affairs. Archived from the original on 9 August 2010. Retrieved 28 March 2010. Jump up ^ `` The treaties control space - related activities of States. What about non-governmental entities active in outer space, like companies and even individuals ? ''. United Nations Office for Outer Space Affairs. Archived from the original on 21 April 2010. Retrieved 28 March 2010. Jump up ^ `` Statement by the Board of Directors of the IISL On Claims to Property Rights Regarding The Moon and Other Celestial Bodies ( 2004 ) '' ( PDF ). International Institute of Space Law. 2004. Archived ( PDF ) from the original on 22 December 2009. Retrieved 28 March 2010. Jump up ^ `` Further Statement by the Board of Directors of the IISL On Claims to Lunar Property Rights ( 2009 ) '' ( PDF ). International Institute of Space Law. 22 March 2009. Archived ( PDF ) from the original on 22 December 2009. Retrieved 28 March 2010. Jump up ^ `` Carved and Drawn Prehistoric Maps of the Cosmos ''. Space Today. 2006. Archived from the original on 15 March 2012. Retrieved 12 April 2007. ^ Jump up to : Dexter, Miriam Robbins ( 1984 ). `` Proto - Indo - European Sun Maidens and Gods of the Moon ''. Mankind Quarterly. 25 ( 1 & 2 ) : 137 -- 144. ^ Jump up to : Nemet - Nejat, Karen Rhea ( 1998 ), Daily Life in Ancient Mesopotamia, Daily Life, Greenwood, p. 203, ISBN 978 - 0313294976 ^ Jump up to : Black, Jeremy ; Green, Anthony ( 1992 ). Gods, Demons and Symbols of Ancient Mesopotamia : An Illustrated Dictionary. The British Museum Press. p. 135. ISBN 0 - 7141 - 1705 - 6. Jump up ^ Zschietzschmann, W. ( 2006 ). Hellas and Rome : The Classical World in Pictures. Whitefish, Montana : Kessinger Publishing. p. 23. ISBN 9781428655447. Jump up ^ Cohen, Beth ( 2006 ). `` Outline as a Special Technique in Black - and Red - figure Vase - painting ''. The Colors of Clay : Special Techniques in Athenian Vases. Los Angeles, California : Getty Publications. pp. 178 -- 179. ISBN 9780892369423. Jump up ^ `` Muhammad. '' Encyclopædia Britannica. 2007. Encyclopædia Britannica Online, p. 13 Jump up ^ Marshack, Alexander ( 1991 ), The Roots of Civilization, Colonial Hill, Mount Kisco, NY. Jump up ^ Brooks, A.S. and Smith, C.C. ( 1987 ) : `` Ishango revisited : new age determinations and cultural interpretations '', The African Archaeological Review, 5 : 65 -- 78. Jump up ^ Duncan, David Ewing ( 1998 ). The Calendar. Fourth Estate Ltd. pp. 10 -- 11. ISBN 978 - 1 - 85702 - 721 - 1. Jump up ^ For etymology, see Barnhart, Robert K. ( 1995 ). The Barnhart Concise Dictionary of Etymology. Harper Collins. p. 487. ISBN 978 - 0 - 06 - 270084 - 1... For the lunar calendar of the Germanic peoples, see Birley, A.R. ( Trans. ) ( 1999 ). Agricola and Germany. Oxford World 's Classics. USA : Oxford University Press. p. 108. ISBN 978 - 0 - 19 - 283300 - 6. Jump up ^ Mallory, J.P. ; Adams, D.Q. ( 2006 ). The Oxford Introduction to Proto - Indo - European and the Proto - Indo - European World. Oxford Linguistics. Oxford University Press. pp. 98, 128, 317. ISBN 978 - 0 - 19 - 928791 - 8. Jump up ^ Harper, Douglas. `` measure ''. Online Etymology Dictionary. Jump up ^ Harper, Douglas. `` menstrual ''. Online Etymology Dictionary. Jump up ^ Smith, William George ( 1849 ). Dictionary of Greek and Roman Biography and Mythology : Oarses - Zygia. 3. J. Walton. p. 768. Retrieved 29 March 2010. Jump up ^ Estienne, Henri ( 1846 ). Thesaurus graecae linguae. 5. Didot. p. 1001. Retrieved 29 March 2010. Jump up ^ mensis. Charlton T. Lewis and Charles Short. A Latin Dictionary on Perseus Project. Jump up ^ μείς in Liddell and Scott. Jump up ^ `` Islamic Calendars based on the Calculated First Visibility of the Lunar Crescent ''. University of Utrecht. Archived from the original on 11 January 2014. Retrieved 11 January 2014. ^ Jump up to : Lilienfeld, Scott O. ; Arkowitz, Hal ( 2009 ). `` Lunacy and the Full Moon ''. Scientific American. Archived from the original on 16 October 2009. Retrieved 13 April 2010. Jump up ^ Rotton, James ; Kelly, I.W. ( 1985 ). `` Much ado about the full moon : A meta - analysis of lunar - lunacy research ''. Psychological Bulletin. 97 ( 2 ) : 286 -- 306. doi : 10.1037 / 0033 - 2909.97. 2.286. Jump up ^ Martens, R. ; Kelly, I.W. ; Saklofske, D.H. ( 1988 ). `` Lunar Phase and Birthrate : A 50 - year Critical Review ''. Psychological Reports. 63 ( 3 ) : 923 -- 934. doi : 10.2466 / pr0. 1988.63. 3.923. Jump up ^ Kelly, Ivan ; Rotton, James ; Culver, Roger ( 1986 ), `` The Moon Was Full and Nothing Happened : A Review of Studies on the Moon and Human Behavior '', Skeptical Inquirer, 10 ( 2 ) : 129 -- 43. Reprinted in The Hundredth Monkey - and other paradigms of the paranormal, edited by Kendrick Frazier, Prometheus Books. Revised and updated in The Outer Edge : Classic Investigations of the Paranormal, edited by Joe Nickell, Barry Karr, and Tom Genoni, 1996, CSICOP. Jump up ^ Foster, Russell G. ; Roenneberg, Till ( 2008 ). `` Human Responses to the Geophysical Daily, Annual and Lunar Cycles ''. Current Biology. 18 ( 17 ) : R784 -- R794. doi : 10.1016 / j. cub. 2008.07. 003. PMID 18786384. Bibliography Needham, Joseph ( 1986 ). Science and Civilization in China, Volume III : Mathematics and the Sciences of the Heavens and Earth. Taipei : Caves Books. ISBN 978 - 0 - 521 - 05801 - 8. Further reading `` Revisiting the Moon ''. New York Times. Retrieved 8 September 2014. The Moon. Discovery 2008. BBC World Service. Bussey, B. ; Spudis, P.D. ( 2004 ). The Clementine Atlas of the Moon. Cambridge University Press. ISBN 0 - 521 - 81528 - 2. Cain, Fraser. `` Where does the Moon Come From ? ''. Universe Today. Retrieved 1 April 2008. ( podcast and transcript ) Jolliff, B. ( 2006 ). Wieczorek, M. ; Shearer, C. ; Neal, C., eds. `` New views of the Moon ''. Reviews in Mineralogy and Geochemistry. Chantilly, Virginia : Mineralogy Society of America. 60 ( 1 ) : 721. Bibcode : 2006RvMG... 60D... 5J. doi : 10.2138 / rmg. 2006.60. 0. ISBN 0 - 939950 - 72 - 3. Retrieved 12 April 2007. Jones, E.M. ( 2006 ). `` Apollo Lunar Surface Journal ''. NASA. Retrieved 12 April 2007. `` Exploring the Moon ''. Lunar and Planetary Institute. Retrieved 12 April 2007. Mackenzie, Dana ( 2003 ). The Big Splat, or How Our Moon Came to Be. Hoboken, New Jersey : John Wiley & Sons. ISBN 0 - 471 - 15057 - 6. Moore, P. ( 2001 ). On the Moon. Tucson, Arizona : Sterling Publishing Co. ISBN 0 - 304 - 35469 - 4. `` Moon Articles ''. Planetary Science Research Discoveries. Hawai'i Institute of Geophysics and Planetology. Spudis, P.D. ( 1996 ). The Once and Future Moon. Smithsonian Institution Press. ISBN 1 - 56098 - 634 - 4. Taylor, S.R. ( 1992 ). Solar system evolution. Cambridge University Press. p. 307. ISBN 0 - 521 - 37212 - 7. Teague, K. ( 2006 ). `` The Project Apollo Archive ''. Retrieved 12 April 2007. Wilhelms, D.E. ( 1987 ). `` Geologic History of the Moon ''. U.S. Geological Survey Professional paper. 1348. Retrieved 12 April 2007. Wilhelms, D.E. ( 1993 ). To a Rocky Moon : A Geologist 's History of Lunar Exploration. Tucson, Arizona : University of Arizona Press. ISBN 0 - 8165 - 1065 - 2. Retrieved 10 March 2009. External links Find more aboutMoon at Wikipedia 's sister projects Definitions from Wiktionary Media from Wikimedia Commons News from Wikinews Quotations from Wikiquote Texts from Wikisource Textbooks from Wikibooks Travel guide from Wikivoyage Learning resources from Wikiversity NASA images and videos about the Moon Album of images and high - resolution overflight videos by Seán Doran, based on LRO data Cartographic resources The Moon on Google Maps, a 3 - D rendition of the moon akin to Google Earth `` Consolidated Lunar Atlas ''. Lunar and Planetary Institute. Retrieved 26 February 2012. Gazetteer of Planetary Nomenclature ( USGS ) List of feature names. `` Clementine Lunar Image Browser ''. U.S. Navy. 15 October 2003. Retrieved 12 April 2007. 3D zoomable globes : `` Google Moon ''. Google. 2007. Retrieved 12 April 2007. `` Moon ''. World Wind Central. NASA. 2007. Retrieved 12 April 2007. Aeschliman, R. `` Lunar Maps ''. Planetary Cartography and Graphics. Retrieved 12 April 2007. Maps and panoramas at Apollo landing sites Japan Aerospace Exploration Agency ( JAXA ) Kaguya ( Selene ) images Large image of the Moon 's north pole area Observation tools `` NASA 's SKYCAL -- Sky Events Calendar ''. NASA. Archived from the original on 20 August 2007. Retrieved 27 August 2007. `` Find moonrise, moonset and moonphase for a location ''. 2008. Retrieved 18 February 2008. `` HMNAO 's Moon Watch ''. 2005. Retrieved 24 May 2009. See when the next new crescent moon is visible for any location. General Lunar shelter ( building a lunar base with 3D printing ) The Moon Physical features Face on the Moon Internal structure Gravity field Topography Magnetic field Atmosphere Ion tail Moonlight Lunar swirls Orbit Orbit of the Moon Phases Lunation Lunar libration Full Moon Lunar terminator Full moon cycle Earthshine Lunar eclipse Solar eclipse Solar eclipses on the Moon Tide Surface Selenography Near side Far side North pole South pole Lunar mare List Craters List Calderas Mountains Valleys Volcanic features South Pole -- Aitken basin Shackleton crater Water Soil Ray systems Peak of eternal light Crater of eternal darkness Space weathering Transient lunar phenomenon Lunar basalt 70017 Science Geology timescale Giant - impact hypothesis Hill sphere Moon rocks Lunar meteorites KREEP Late Heavy Bombardment Lunar laser ranging ALSEP Observation Origin Lunar sample displays Apollo 11 lunar sample display Apollo 17 lunar sample display Exploration Apollo program Exploration of the Moon Colonization of the Moon List of lunar probes List of missions to the Moon Moon landing conspiracy theories Related topics Lunar calendar Lunisolar calendar Craters named after people Double planet Lunar effect Man in the Moon Memorials on the Moon Month Lunar month Moon illusion Harvest moon Hunter 's moon Moon in art and literature Moon in mythology Hjúki and Bil ( Norse legends ) Moon is made of green cheese Natural satellite Solar System Supermoon Theia Tourism Phases / Occurrence Black moon Blue moon Lunar phase New moon Dark moon Wet moon Lilith ( hypothetical moon ) Moon portal Earth sciences portal Solar System portal Earth - related topics History Age of the Earth Evolutionary history of life Faint young Sun paradox Formation and evolution of the Solar System Future of Earth Geologic time scale Geological history of Earth History of Earth Timeline of evolution Geography Geology Clairaut 's theorem Continents Earthquake Equatorial bulge Extremes on Earth Geology of solar terrestrial planets Geophysics Plate tectonics Structure of the Earth Time zones Ecology Earth Day Global warming Human impact on the environment Imaging Apple Maps Baidu Maps Bhuvan Bing Maps Global Map Google Earth Google Maps MapmyIndia NASA World Wind Here OpenStreetMap Wikimapia Remote sensing Yahoo ! Maps Yandex Maps Arts Culture Society Earth in culture Earth in science fiction Etymology of the word `` Earth '' History of the world International law Landscape painting List of countries World economy Other topics Biosphere Earth 's orbit Earth trojan The ecliptic Flag of Earth Gravity Magnetic field The Moon Claimed moons of Earth 2006 RH120 Kordylewski cloud Solar System Earth 's location in the Universe Theia Earth sciences portal Solar System portal Natural satellites of the Solar System Planetary satellites Terrestrial Martian Jovian Saturnian Uranian Neptunian Other satellites Minor - planet moons Plutonian Haumean Eridian Makemakean Largest satellites ( mean radius ≥ 100 km ) size Ganymede largest / 2634 km / 0.413 Earths Titan Callisto Io Moon Europa Triton Titania Rhea Oberon Iapetus Charon Umbriel Ariel Dione Tethys ( Dysnomia ) Enceladus Miranda Proteus Mimas ( Hi'iaka ) Nereid Hyperion Phoebe smallest / 106 km / 0.017 Earths abc 's Ariel Callisto Charon Dione ( Dysnomia ) Enceladus Europa Ganymede ( Hi'iaka ) Hyperion Iapetus Io Mimas Miranda Moon Nereid Oberon Phoebe Proteus Rhea Tethys Titan Titania Triton Umbriel Discovery timeline Inner moons Irregular moons List Naming Regular moons Trojan moons NOTE : Italicized moons are not close to being in hydrostatic equilibrium ; ( bracketed ) moons may or may not be close to being in hydrostatic equilibrium. The Solar System The Sun Mercury Venus Earth Mars Ceres Jupiter Saturn Uranus Neptune Pluto Haumea Makemake Eris Planets Terrestrial planets Mercury Venus Earth Mars Giant planets Jupiter Saturn Uranus Neptune Dwarf planets Ceres Pluto Haumea Makemake Eris Rings Jovian Saturnian ( Rhean ) Charikloan Chironean Uranian Neptunian Haumean Moons Terrestrial Moon Other near - Earth objects Martian Phobos Deimos Jovian Ganymede Callisto Io Europa all 69 Saturnian Titan Rhea Iapetus Dione Tethys Enceladus Mimas Hyperion Phoebe all 62 Uranian Titania Oberon Umbriel Ariel Miranda all 27 Neptunian Triton Proteus Nereid all 14 Plutonian Charon Nix Hydra Kerberos Styx Haumean Hiʻiaka Namaka Makemakean S / 2015 ( 136472 ) 1 Eridian Dysnomia Lists Solar System objects By size By discovery date Minor planets Gravitationally rounded objects Possible dwarf planets Natural satellites Comets Small Solar System bodies Meteoroids Minor planets moons Comets Damocloids Mercury - crossers Venus - crossers Venus trojans Near - Earth objects Earth - crossers Earth trojans Mars - crossers Mars trojans Asteroid belt Asteroids first discovered : Ceres Pallas Juno Vesta Families Notable asteroids Kirkwood gap Main - belt comets Jupiter trojans Jupiter - crossers Centaurs Saturn - crossers Uranus trojans Uranus - crossers Neptune trojans Cis - Neptunian objects Trans - Neptunian objects Neptune - crossers Plutoids Kuiper belt Plutinos Cubewanos Scattered disc Detached objects Sednoids Hills cloud Oort cloud Hypothetical objects Vulcan Vulcanoids Phaeton Planet V Theia Fifth giant Planets beyond Neptune Tyche Nemesis Planet Nine Exploration ( outline ) Discovery Astronomy Timeline Spaceflight Robotic spacecraft Human spaceflight Colonization List of probes Timeline Mercury Venus Moon Mars Ceres Asteroids Mining Comets Jupiter Saturn Uranus Neptune Pluto Deep space Outline of the Solar System Portals Solar System Astronomy Earth sciences Mars Jupiter Uranus Cosmology Solar System → Local Interstellar Cloud → Local Bubble → Gould Belt → Orion Arm → Milky Way → Milky Way subgroup → Local Group → Virgo Supercluster → Laniakea Supercluster → Observable universe → Universe Each arrow ( → ) may be read as `` within '' or `` part of ''. VIAF : 311490648 LCCN : sh85087107 GND : 1085673251 SUDOC : 027282414 BNF : cb119358377 ( data ) NDL : 00573509 NKC : ph117905 BNE : XX456648 Retrieved from `` https://en.wikipedia.org/w/index.php?title=Moon&oldid=817835022 '' Categories : Moon Astronomical objects known since antiquity Hidden categories : Webarchive template wayback links Articles containing Ancient Greek - language text Wikipedia indefinitely semi-protected pages Wikipedia indefinitely move - protected pages Use dmy dates from September 2017 Articles containing Greek - language text Accuracy disputes from December 2017 Articles containing Latin - language text Articles containing German - language text Articles with hAudio microformats Articles containing Arabic - language text Featured articles Wikipedia articles with VIAF identifiers Wikipedia articles with LCCN identifiers Wikipedia articles with GND identifiers Wikipedia articles with BNF identifiers Articles containing video clips Talk View source Contents About Wikipedia Wikinews Wikiquote Wikiversity Wikivoyage Адыгэбзэ Afrikaans Alemannisch አማርኛ Ænglisc Аҧсшәа Aragonés ܐܪܡܝܐ Armãneashti Arpetan অসমীয়া Asturianu Avañe'ẽ Авар Aymar aru Azərbaycanca تۆرکجه বাংলা Bân - lâm - gú Башҡортса Беларуская Беларуская ( тарашкевіца ) ‎ भोजपुरी Български Boarisch བོད ་ ཡིག Bosanski Brezhoneg Буряад Català Cebuano Čeština ChiShona Corsu Cymraeg Dansk Davvisámegiella Deutsch ދިވެހިބަސް Diné bizaad Eesti Ελληνικά Emiliàn e rumagnòl Эрзянь Español Esperanto Estremeñu Euskara فارسی Fiji Hindi Føroyskt Français Fulfulde Furlan Gaeilge Gaelg Gàidhlig Galego 贛 語 ગુજરાતી 客家 語 / Hak - kâ - ngî 한국어 Hausa Hawaiʻi Հայերեն हिन्दी Hornjoserbsce Hrvatski Ido Ilokano Bahasa Indonesia Interlingua Interlingue ᐃᓄᒃᑎᑐᑦ / inuktitut Ирон IsiZulu Íslenska Italiano עברית Basa Jawa Kalaallisut ಕನ್ನಡ Kapampangan ქართული कॉशुर / کٲشُر Kaszëbsczi Қазақша Kernowek Kiswahili Коми Kreyòl ayisyen Kurdî Кыргызча Ladino Лезги ລາວ Latina Latviešu Lëtzebuergesch Lietuvių Ligure Limburgs Lingála La. lojban. Lumbaart Magyar Македонски Malagasy മലയാളം Malti मराठी მარგალური مصرى Bahasa Melayu Mìng - dĕ̤ng - ngṳ̄ Mirandés Мокшень Монгол မြန်မာဘာသာ Nāhuatl Dorerin Naoero Nederlands Nedersaksies नेपाली नेपाल भाषा 日本 語 Napulitano Нохчийн Nordfriisk Norsk Norsk nynorsk Nouormand Novial ꆇꉙ Occitan ଓଡ଼ିଆ Oʻzbekcha / ўзбекча ਪੰਜਾਬੀ پنجابی پښتو Patois Перем Коми ភាសា ខ្មែរ Piemontèis Tok Pisin Plattdüütsch Polski Ποντιακά Português Qaraqalpaqsha Qırımtatarca Ripoarisch Română Romani Rumantsch Runa Simi Русиньскый Русский Саха тыла संस्कृतम् Sardu Scots Seeltersk Shqip Sicilianu සිංහල Simple English سنڌي Slovenčina Slovenščina Словѣньскъ / ⰔⰎⰑⰂⰡⰐⰠⰔⰍⰟ Ślůnski Soomaaliga کوردی Српски / srpski Srpskohrvatski / српскохрватски Basa Sunda Suomi Svenska Tagalog தமிழ் Taqbaylit Татарча / tatarça తెలుగు ไทย Тоҷикӣ ᏣᎳᎩ Tsetsêhestâhese ತುಳು Türkçe Türkmençe Twi Тыва дыл Удмурт Українська اردو Vahcuengh Vèneto Vepsän kel ' Tiếng Việt Volapük Võro Walon 文言 West - Vlams Winaray 吴语 ייִדיש Yorùbá 粵語 Zeêuws Žemaitėška 中文 डोटेली Kabɩyɛ Edit links This page was last edited on 30 December 2017, at 21 : 25. Text is available under the Creative Commons Attribution - ShareAlike License ; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia ® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization. About Wikipedia

Question: where does the name of the moon come from
Answer: from moone (around 1380), which developed from mone (1135), which is derived from Old English mōna (dating from before 725), which ultimately stems from Proto-Germanic *mǣnōn