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Encyclopedia > Moon
Moon  

The Moon as seen by an observer on Earth
Orbital characteristics
Perigee: 363,104 km
0.0024 AU
Apogee 405,696 km
0.0027 AU
Semi-major axis: 384,399 km
0.00257 AU [1]
Eccentricity: 0.0549 [1]
Orbital period: 27.321582 d
27 d 7 h 43.1 min [1]
Synodic period: 29.530588 d
29 d 12 h 44.0 min
Avg. orbital speed: 1.022 km/s
Inclination: 5.145° to ecliptic [1]
(between 18.29° and 28.58° to Earth's equator)
Longitude of ascending node: regressing,
1 revolution in 18.6 years
Argument of perigee: progressing,
1 revolution in 8.85 years
Satellite of: Earth
Physical characteristics
Mean radius: 1,737.10 km
0.273 Earths [1]
Equatorial radius: 1,738.14 km
0.273 Earths
Polar radius: 1,735.97 km
0.273 Earths
Flattening: 0.00125
Circumference: 10,921 km (equatorial)
Surface area: 3.793×107 km²
0.074 Earths
Volume: 2.1958×1010 km³
0.020 Earths
Mass: 7.3477×1022 kg
0.0123 Earths [1]
Mean density: 3,346.4 kg/m³ [1]
Equatorial surface gravity: 1.622 m/s²
0.1654 g
Escape velocity: 2.38 km/s
Sidereal rotation period: 27.321582 d (synchronous)
Rotation velocity at equator: 4.627 m/s
Axial tilt: 1.5424° (to ecliptic)
6.687° (to orbit plane)
Albedo: 0.12
Surface temp.:
   equator
   85°N [5]
min mean max
100 K 220 K 390 K
70 K 130 K 230 K
Apparent magnitude: –2.5 to –12.9 [2]
–12.74 (mean full moon)[3]
Angular diameter: 29.3′ — 34.1' [3][4]
Adjectives: lunar
Atmosphere [6][7]
Surface pressure: 10-7 Pa (day)
10-10 Pa (night)

The Moon (Latin: Luna) is Earth's only natural satellite, and the fifth largest moon in the Solar System. The average centre-to-centre distance from the Earth to the Moon is 384,403 km, which is about thirty times the diameter of the Earth. The Moon has a diameter of 3,474 km [8]—slightly more than a quarter that of the Earth and slightly smaller than the east-west distance across the United States. This means that the volume of the Moon is about 2 percent that of Earth. The gravitational pull at its surface is about 17 percent of the Earth's. The Moon makes a complete orbit around the Earth every 27.3 days, and the periodic variations in the geometry of the Earth–Moon–Sun system are responsible for the lunar phases that repeat every 29.5 days. A natural satellite is an object that orbits a planet or other body larger than itself and which is not man-made. ... The NOUN Moon refers, among other things, to: Look up moon in Wiktionary, the free dictionary A common term for large natural satellites of a planet. ... Image File history File links Moon_symbol_decrescent. ... Image File history File links Metadata Size of this preview: 594 × 599 pixelsFull resolution (1411 × 1424 pixel, file size: 903 KB, MIME type: image/jpeg) File historyClick on a date/time to view the file as it appeared at that time. ... This article is about Earth as a planet. ... Two bodies with a slight difference in mass orbiting around a common barycenter. ... A diagram of Keplerian orbital elements. ... The astronomical unit (AU or au or a. ... A diagram of Keplerian orbital elements. ... The semi-major axis of an ellipse In geometry, the term semi-major axis (also semimajor axis) is used to describe the dimensions of ellipses and hyperbolae. ... (This page refers to eccitricity in astrodynamics. ... The orbital period is the time it takes a planet (or another object) to make one full orbit. ... The orbital period is the time it takes a planet (or another object) to make one full orbit. ... The orbital speed of a body, generally a planet, a natural satellite, an artificial satellite, or a multiple star, is the speed at which it orbits around the barycenter of a system, usually around a more massive body. ... For the science fiction novella by William Shunn, see Inclination (novella). ... The plane of the ecliptic is well seen in this picture from the 1994 lunar prospecting Clementine spacecraft. ... The Longitude of the ascending node (☊, also noted Ω) is one of the orbital elements used to specify the orbit of an object in space. ... The argument of periapsis (ω) is the orbital element describing the angle between an orbiting bodys ascending node (the point where the body crosses the plane of reference from South to North) and its periapsis (the point of closest approach to the central body), measured in the orbital plane and... A natural satellite is an object that orbits a planet or other body larger than itself and which is not man-made. ... This article is about Earth as a planet. ... World map showing the equator in red In tourist areas, the equator is often marked on the sides of roads The equator marked as it crosses Ilhéu das Rolas, in São Tomé and Príncipe. ... A geographical pole is either of two fixed points on the surface of a spinning body or planet, at 90 degrees from the equator, based on the axis around which a body spins. ... The flattening, ellipticity, or oblateness of an oblate spheroid is the relative difference between its equatorial radius a and its polar radius b: The flattening of the Earth is 1:298. ... World map showing the equator in red In tourist areas, the equator is often marked on the sides of roads The equator marked as it crosses Ilhéu das Rolas, in São Tomé and Príncipe. ... In mathematics, a spheroid is a quadric surface in three dimensions obtained by rotating an ellipse about one of its principal axes. ... For other uses, see Volume (disambiguation). ... For other uses, see Mass (disambiguation). ... For other uses, see Density (disambiguation). ... The surface gravity of a Killing horizon is the acceleration, as exerted at infinity, needed to keep an object at the horizon. ... The term g force or gee force refers to the symbol g, the force of acceleration due to gravity at the earths surface. ... Space Shuttle Atlantis launches on mission STS-71. ... On a prograde planet like the Earth, the sidereal day is shorter than the solar day. ... Due to synchronous rotation of their moon, the inhabitants of the central body will never be able to see its green side. ... In astronomy, axial tilt is the inclination angle of a planets rotational axis in relation to a perpendicular to its orbital plane. ... For other uses, see Albedo (disambiguation). ... For other uses, see Temperature (disambiguation). ... For other uses, see Kelvin (disambiguation). ... The apparent magnitude (m) of a star, planet or other celestial body is a measure of its apparent brightness as seen by an observer on Earth. ... For other uses, see Full Moon. ... The angular diameter of an object as seen from a given position is the diameter measured as an angle. ... Diurnal (daily) rhythm of air pressure in northern Germany (black curve is air pressure) Atmospheric pressure is the pressure at any point in the Earths atmosphere. ... For other uses, see Pascal. ... For other uses, see Pascal. ... For other uses, see Latin (disambiguation). ... This article is about Earth as a planet. ... A natural satellite is an object that orbits a planet or other body larger than itself and which is not man-made. ... This is a list of natural satellites in the solar system, ordered from largest to smallest by average diameter. ... This article is about the Solar System. ... Gravity redirects here. ... Two bodies with a slight difference in mass orbiting around a common barycenter. ... Sol redirects here. ... Lunar phase refers to the appearance of the illuminated portion of the Moon as seen by an observer, usually on Earth. ...


The Moon is the only celestial body to which humans have travelled and upon which humans have landed. The first artificial object to escape Earth's gravity and pass near the Moon was the Soviet Union's Luna 1, the first artificial 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.[8] The United States (U.S.) Apollo program achieved the only manned missions to date, resulting in six landings between 1969 and 1972. Human exploration of the Moon ceased with the conclusion of the Apollo program, although several countries have announced plans to send people or robotic spacecraft to the Moon. Astronomical objects are significant physical entities, associations or structures which current science has confirmed to exist in space. ... Luna 1 is the first spacecraft to reach the vicinity of the Moon and the first of the Luna programme of Soviet automatic interplanetary stations successfully launched in the direction of the Moon. ... Luna 2 (E-1A series) was the second of the Soviet Unions Luna program spacecraft launched in the direction of the Moon. ... Far side of the Moon. ... Luna 3 (E-3 series) was the third spacecraft sent successfully to the moon and was an early triumph in the human exploration of outer space. ... Luna 9 (E-6 series), also known as Lunik 9 (internal name E-6 N. 13), was an unmanned space mission of the Soviet Unions Luna program. ... Luna 10 was an unmanned space mission of the Luna program, also called Lunik 10. ... This article is about the series of human spaceflight missions. ...

Contents

Name and etymology

Unlike the moons of other planets, the moon of the Earth has no proper English name other than "the Moon" (capitalized). The English language is a West Germanic language that originates in England. ...


The word moon is a Germanic word, related to Latin mensis; it is ultimately a derivative of the Proto-Indo-European root me-, also represented in measure[9] (time), with reminders of its importance in measuring time in words derived from it like Monday, month and menstrual. In English, the word moon exclusively meant "the Moon" until 1665, when it was extended to refer to the recently-discovered natural satellites of other planets.[9] The Moon is occasionally referred to by its Latin name, Luna, in order to distinguish it from other natural satellites, with a related adjective lunar, and an adjectival prefix seleno- or suffix -selene (from the Greek deity Selene). The Germanic languages are a group of related languages constituting a branch of the Indo-European (IE) language family. ... This article is about the baked good, for other uses see Pie (disambiguation). ... Look up Month in Wiktionary, the free dictionary. ... A natural satellite is an object that orbits a planet or other body larger than itself and which is not man-made. ... The bust of Zeus found at Otricoli (Sala Rotonda, Museo Pio-Clementino, Vatican) Greek mythology is the body of stories belonging to the Ancient Greeks concerning their gods and heroes, the nature of the world and the origins and significance of their own cult and ritual practices. ... This article is about the Greek goddess. ...


Lunar surface

Main article: Geology of the Moon

Exploring Shorty crater during the Apollo 17 mission to the Moon. ...

Two sides of the Moon

The Moon is in synchronous rotation, meaning that it keeps nearly the same face turned towards the Earth at all times. Early in the Moon's history, its rotation slowed and became locked in this configuration as a result of frictional effects associated with tidal deformations caused by the Earth.[10] Due to synchronous rotation of their moon, the inhabitants of the central body will never be able to see its green side. ... Tidal locking makes one side of an astronomical body always face another, like the Moon facing the Earth. ... For other uses, see Friction (disambiguation). ...


Long ago when the Moon spun much faster, the Moon's tidal bulge preceded the Earth-Moon line because the Moon couldn't "snap back" its bulges quickly enough to keep its bulges in line with Earth.[11] The rotation swept the bulge beyond the Earth-Moon line. This out-of-line bulge caused a torque, slowing the Moon spin, like a wrench tightening a nut. When the Moon's spin slowed enough to match its orbital rate, then the bulge always faced Earth, the bulge was in line with Earth, and the torque disappeared. That's why the Moon rotates at the same rate as it orbits and we always see the same side of the Moon.


Small variations (libration) in the angle from which the Moon is seen allow about 59% of its surface to be seen from the earth (but only half at any instant).[8] Not to be confused with Liberation. ...

 
Near side of the Moon   Far side of the Moon

The side of the Moon that faces Earth is called the near side, and the opposite side the far side. The far side should not be confused with the dark side, which is the hemisphere that is not being illuminated by the Sun at a given moment (this may be the side facing the Earth, as it is once a month during the New Moon phase). The far side of the Moon was first photographed by the Soviet probe Luna 3 in 1959. One distinguishing feature of the far side is its almost complete lack of maria. Download high resolution version (1719x1719, 259 KB) Original Caption Released with Image About 50,000 Clementine images were processed to produce the four orthographic views of the Moon. ... Download high resolution version (1719x1719, 311 KB) Original Caption Released with Image About 50,000 Clementine images were processed to produce the four orthographic views of the Moon. ... The near side of the Moon is the lunar hemisphere that is permanently turned towards the Earth, and as such the side which is always seen. ... Far side of the Moon. ... The near side of the Moon is the lunar hemisphere that is permanently turned towards the Earth, and as such the side which is always seen. ... Far side of the Moon. ... Sol redirects here. ... Luna 3 (E-3 series) was the third spacecraft sent successfully to the moon and was an early triumph in the human exploration of outer space. ... Lunar nearside with major maria and craters labeled A global albedo map of the Moon obtained from the Clementine missionThe dark regions are the lunar maria, whereas the lighter regions are the highlands. ...

Lunar libration

Image File history File links Size of this preview: 598 × 600 pixelsFull resolution‎ (640 × 642 pixels, file size: 9. ... Image File history File links Size of this preview: 598 × 600 pixelsFull resolution‎ (640 × 642 pixels, file size: 9. ... Not to be confused with Liberation. ...

Maria

Main article: Lunar mare

The dark and relatively featureless lunar plains humans can clearly see when the Moon is full are called maria (singular mare), Latin for seas, since they were believed by ancient astronomers to be filled with water. These are now known to be vast solidified pools of ancient basaltic lava. The majority of these lavas erupted or flowed into the depressions associated with impact basins that formed by the collisions of meteors and comets with the lunar surface. (Oceanus Procellarum is a major exception in that it does not correspond to a known impact basin). Maria are found almost exclusively on the near side of the Moon, with the far side having only a few scattered patches covering only about 2% of its surface,[12] compared with about 31% on the near side.[8] The most likely explanation for this difference is related to a higher concentration of heat-producing elements on the near-side hemisphere, as has been demonstrated by geochemical maps obtained from the Lunar Prospector gamma-ray spectrometer.[13][14] Several provinces containing shield volcanoes and volcanic domes are found within the near side maria.[15] Lunar nearside with major maria and craters labeled A global albedo map of the Moon obtained from the Clementine missionThe dark regions are the lunar maria, whereas the lighter regions are the highlands. ... Lunar nearside with major maria and craters labeled A global albedo map of the Moon obtained from the Clementine missionThe dark regions are the lunar maria, whereas the lighter regions are the highlands. ... An astronomer or astrophysicist is a person whose area of interest is astronomy or astrophysics. ... For the cities, see Basalt, Colorado and Basalt, Idaho. ... Tycho crater on Earths moon. ... The Ocean of Storms of the Moon. ... NASAs Lunar Prospector The Lunar Prospector mission was the third selected by NASA for full development and construction as part of the Discovery Program. ... Shield volcano A shield volcano is a large volcano with shallow-sloping side. ... Lunar domes on Mons Rümker. ...


Terrae

The lighter-colored regions of the Moon are called terrae, or more commonly just highlands, since they are higher than most maria. Several prominent mountain ranges on the near side are found along the periphery of the giant impact basins, many of which have been filled by mare basalt. These are believed to be the surviving remnants of the impact basin's outer rims.[16] In contrast to the Earth, no major lunar mountains are believed to have formed as a result of tectonic events.[17] Tycho crater on Earths moon. ...


From images taken by the Clementine mission, it appears that four mountainous regions on the rim of the 73 km-wide Peary crater at the Moon's north pole remain illuminated for the entire lunar day. These peaks of eternal light are possible because of the Moon's extremely small axial tilt to the ecliptic plane. No similar regions of eternal light were found at the south pole, although the rim of Shackleton crater is illuminated for about 80% of the lunar day. Another consequence of the Moon's small axial tilt is regions that remain in permanent shadow at the bottoms of many polar craters.[18] Clementine was a joint space project between the Ballistic Missile Defense Organization (BMDO, previously the Strategic Defense Initiative Organization, or SDIO) and NASA. The objective of the mission was to test sensors and spacecraft components under extended exposure to the space environment and to make scientific observations of the Moon... Peary is the closest large crater to the lunar north pole. ... Peak of Eternal Light (PEL) describes a point on a body within the solar system which is eternally bathed in sunlight. ... The plane of the Ecliptic is well seen in this picture from the 1994 lunar prospecting Clementine spacecraft. ... Shackleton is a lunar crater that lies at the south pole of the Moon. ...


Impact craters

Lunar crater Daedalus on the Moon's far side
Lunar crater Daedalus on the Moon's far side

The Moon's surface shows obvious evidence of having been affected by impact cratering.[19] Impact craters form when asteroids and comets collide with the lunar surface, and globally about half a million craters with diameters greater than 1 km can be found. Since impact craters accumulate at a nearly constant rate, the number of craters per unit area superposed on a geologic unit can be used to estimate the age of the surface (see crater counting). The lack of an atmosphere, weather and recent geological processes ensures that many of these craters have remained relatively well preserved in comparison to those found on Earth. Download high resolution version (900x880, 293 KB)The largest crater in the picture is Daedalus. ... Download high resolution version (900x880, 293 KB)The largest crater in the picture is Daedalus. ... Daedalus is a prominent crater located near the center of the far side of the Moon. ... Tycho crater on Earths moon. ... This article, which relates to the Moon, is a stub. ...


The largest crater on the Moon, which also has the distinction of being the largest known crater in the Solar System, is the South Pole-Aitken basin. This impact basin is located on the far side, between the South Pole and equator, and is some 2240 km in diameter and 13 km in depth.[20] Prominent impact basins on the near side include Imbrium, Serenitatis, Crisium, and Nectaris. The South Pole-Aitken basin is an impact crater on Earths Moon. ... Oblique view of Mare Imbrium looking south towards Copernicus crater. ... A map of Mare Serenitatis. ... Mare Crisium Studios is also the name of a company formed to develop the game Stars! Supernova Genesis. ... The Sea of Nectar (Mare Nectaris) is a small lunar mare or sea (a volcanic lava plain noticeably darker than the rest of the moons surface) located between the Sea of Tranquillity (Mare Tranquillatis) and the Sea of Fecundity (Mare Fecunditatis). ...


Regolith

Blanketed atop the Moon's crust is a highly comminuted (broken into ever smaller particles) and "impact gardened" surface layer called regolith. Since the regolith forms by impact processes, the regolith of older surfaces is generally thicker than for younger surfaces. In particular, it has been estimated that the regolith varies in thickness from about 3–5 m in the maria, and by about 10–20 m in the highlands.[21] Beneath the finely comminuted regolith layer is what is generally referred to as the megaregolith. This layer is much thicker (on the order of tens of kilometres) and comprises highly fractured bedrock.[22] Look up comminution in Wiktionary, the free dictionary. ... Regolith (Greek: blanket rock) is a layer of loose, heterogeneous material covering solid rock. ...


Presence of water

Main article: Lunar ice

The continuous bombardment of the Moon by comets and meteoroids has most likely added small amounts of water to the lunar surface. If so, sunlight would split much of this water into its constituent elements of hydrogen and oxygen, both of which would ordinarily escape into space over time, because of the Moon's weak gravity. However, because of the slightness of the axial tilt of the Moon's spin axis to the ecliptic plane—only 1.5°—some deep craters near the poles never receive direct light from the Sun and are thus in permanent shadow (see Shackleton crater). Water molecules that ended up in these craters could be stable for long periods of time. The continuous bombardment of the Moon by comets and meteoroids have added some amount of water to the lunar surface. ... Comet Hale-Bopp Comet West For other uses, see Comet (disambiguation). ... “Meteor” redirects here. ... Shackleton is a lunar crater that lies at the south pole of the Moon. ...


Clementine has mapped craters at the lunar south pole[23] that are shadowed in this way, and computer simulations suggest that up to 14,000 km² might be in permanent shadow.[18] Results from the Clementine mission bistatic radar experiment are consistent with small, frozen pockets of water close to the surface, and data from the Lunar Prospector neutron spectrometer indicate that anomalously high concentrations of hydrogen are present in the upper metre of the regolith near the polar regions.[24] Estimates for the total quantity of water ice are close to one cubic kilometre. Clementine was a joint space project between the Ballistic Missile Defense Organization (BMDO, previously the Strategic Defense Initiative Organization, or SDIO) and NASA. The objective of the mission was to test sensors and spacecraft components under extended exposure to the space environment and to make scientific observations of the Moon... NASAs Lunar Prospector The Lunar Prospector mission was the third selected by NASA for full development and construction as part of the Discovery Program. ...


Water ice can be mined and then split into its constituent hydrogen and oxygen atoms by means of nuclear generators or electric power stations equipped with solar panels. The presence of usable quantities of water on the Moon is an important factor in rendering lunar habitation cost-effective, since transporting water from Earth would be prohibitively expensive. However, recent observations made with the Arecibo planetary radar suggest that some of the near-polar Clementine radar data that were previously interpreted as being indicative of water ice might instead be a result of rocks ejected from young impact craters.[25] The question of how much water there is on the Moon has not been resolved. An artists rendering of a lunar base. ... The Arecibo Observatory is located approximately 9 miles south-southwest from Arecibo, Puerto Rico (near the extreme southwestern corner of Arecibo pueblo). ...


Physical characteristics

Internal structure

Schematic illustration of the internal structure of the Moon

The Moon is a differentiated body, being composed of a geochemically distinct crust, mantle, and core. This structure is believed to have resulted from the fractional crystallization of a magma ocean shortly after its formation about 4.5 billion years ago. The energy required to melt the outer portion of the Moon is commonly attributed to a giant impact event that is postulated to have formed the Earth-Moon system, and the subsequent reaccretion of material in Earth orbit. Crystallization of this magma ocean would have given rise to a mafic mantle and a plagioclase-rich crust (see Origin and geologic evolution below). Schematic illustration of the internal structure of the Moon. ... Image File history File links Moon_Schematic_Cross_Section. ... Image File history File links Moon_Schematic_Cross_Section. ... In cosmogony, planetary differentiation is a process by which the denser portions of a planet will sink to the center; while less dense materials rise to the surface. ... Earth cutaway from core to exosphere. ... Earth cutaway from core to exosphere. ... The planetary core consists of the innermost layer(s) of a planet. ... In chemistry, Fractional Crystallization is a method of refining substances based on differences in soluability. ... This article, which relates to the Moon, is a stub. ... The Big Splash redirects here. ... In geology, mafic minerals and rocks are silicate minerals, magmas, and volcanic and intrusive igneous rocks that have relatively high concentrations of the heavier elements. ... Lunar Ferroan Anorthosite #60025 (Plagioclase Feldspar). ...


Geochemical mapping from orbit implies that the crust of the Moon is largely anorthositic in composition,[6] consistent with the magma ocean hypothesis. In terms of elements, the crust is composed primarily of oxygen, silicon, magnesium, iron, calcium, and aluminium. Based on geophysical techniques, its thickness is estimated to be on average about 50 km.[1] Anorthosite is a phaneritic, intrusive igneous rock characterized by a predominance of plagioclase feldspar (90-100%), and a minimal mafic component (0-10%). Pyroxene, ilmenite, magnetite, and olivine are the mafic minerals most commonly present. ... General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) pale blue (liquid) Standard atomic weight 15. ... Not to be confused with Silicone. ... General Name, symbol, number magnesium, Mg, 12 Chemical series alkaline earth metals Group, period, block 2, 3, s Appearance silvery white solid at room temp Standard atomic weight 24. ... For other uses, see Iron (disambiguation). ... For other uses, see Calcium (disambiguation). ... Aluminum redirects here. ...


Partial melting within the mantle of the Moon gave rise to the eruption of mare basalts on the lunar surface. Analyses of these basalts indicate that the mantle is composed predominantly of the minerals olivine, orthopyroxene and clinopyroxene, and that the lunar mantle is more iron rich than that of the Earth. Some lunar basalts contain high abundances of titanium (present in the mineral ilmenite), suggesting that the mantle is highly heterogeneous in composition. Moonquakes have been found to occur deep within the mantle of the Moon about 1,000 km below the surface. These occur with monthly periodicities and are related to tidal stresses caused by the eccentric orbit of the Moon about the Earth.[1] The mineral olivine (also called chrysolite and, when gem-quality, peridot) is a magnesium iron silicate with the formula (Mg,Fe)2SiO4. ... Figure 1:Mantle-peridotite xenolith with green peridot olivine and black pyroxene crystals from San Carlos Indian Reservation, Gila Co. ... Figure 1:Mantle-peridotite xenolith with green peridot olivine and black pyroxene crystals from San Carlos Indian Reservation, Gila Co. ... General Name, symbol, number titanium, Ti, 22 Chemical series transition metals Group, period, block 4, 4, d Appearance silvery metallic Standard atomic weight 47. ... Ilmenite is a weakly magnetic iron-black or steel-gray mineral found in metamorphic and igneous rocks. ...


The Moon has a mean density of 3,346.4 kg/m³, making it the second densest moon in the Solar System after Io. Nevertheless, several lines of evidence imply that the core of the Moon is small, with a radius of about 350 km or less.[1] This corresponds to only about 20% the size of the Moon, in contrast to about 50% as is the case for most other terrestrial bodies. The composition of the lunar core is not well constrained, but most believe that it is composed of metallic iron alloyed with a small amount of sulfur and nickel. Analyses of the Moon's time-variable rotation indicate that the core is at least partly molten.[26] Atmosphere Surface pressure: trace Composition: 90% sulfur dioxide Io (eye-oe, IPA: , Greek Ῑώ) is the innermost of the four Galilean moons of Jupiter and, with a diameter of 3,642 kilometers, is the fourth largest moon in the Solar System. ... This article is about the chemical element. ... For other uses, see Nickel (disambiguation). ...


Topography

Topography of the Moon, referenced to the lunar geoid
Topography of the Moon, referenced to the lunar geoid

The topography of the Moon has been measured by the methods of laser altimetry and stereo image analysis, most recently from data obtained during the Clementine mission. The most visible topographic feature is the giant far side South Pole-Aitken basin, which possesses the lowest elevations of the Moon. The highest elevations are found just to the north-east of this basin, and it has been suggested that this area might represent thick ejecta deposits that were emplaced during an oblique South Pole-Aitken basin impact event. Other large impact basins, such as Imbrium, Serenitatis, Crisium, Smythii, and Orientale, also possess regionally low elevations and elevated rims. Another distinguishing feature of the Moon's shape is that the elevations are on average about 1.9 km higher on the far side than the near side.[1] Topography of the Moon, referenced to the lunar geoid. ... Image File history File links MoonTopoGeoidUSGS.jpg‎ File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Image File history File links MoonTopoGeoidUSGS.jpg‎ File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... For discussion of land surfaces themselves, see Terrain. ... Clementine was a joint space project between the Ballistic Missile Defense Organization (BMDO, previously the Strategic Defense Initiative Organization, or SDIO) and NASA. The objective of the mission was to test sensors and spacecraft components under extended exposure to the space environment and to make scientific observations of the Moon... The South Pole-Aitken basin is an impact crater on Earths Moon. ... In volcanology, ejecta consists of particles that came out of a volcanic vent, traveled though the air or under water, and fell back on the ground surface or on the ocean floor. ... Oblique view of Mare Imbrium looking south towards Copernicus crater. ... A map of Mare Serenitatis. ... Mare Crisium Studios is also the name of a company formed to develop the game Stars! Supernova Genesis. ... Mare Smythii (sea of William Henry Smyth) is a lunar mare located along the equator on the easternmost edge of the lunar near side. ... 1967 photograph made by NASAs Lunar Orbiter 4 Like a target ring bulls-eye, the lunar mare Mare Orientale (the eastern sea) is one of the most striking large scale lunar features. ...


Gravity field

Main article: Gravity of the Moon

The gravitational field of the Moon has been determined through tracking of radio signals emitted by orbiting spacecraft. The principle used depends on the Doppler effect, whereby the spacecraft acceleration in the line-of-sight direction can be determined by means of small shifts in frequency of the radio signal, and the distance from the spacecraft to a station on Earth. However, because of the Moon's synchronous rotation it is not possible to track spacecraft much over the limbs of the Moon, and the farside gravity field is thus only poorly characterised.[27] Radial gravitational anomaly at the surface of the Moon. ... A source of waves moving to the left. ... Due to synchronous rotation of their moon, the inhabitants of the central body will never be able to see its green side. ...

Radial gravitational anomaly at the surface of the Moon

The major characteristic of the Moon's gravitational field is the presence of mascons, which are large positive gravitational anomalies associated with some of the giant impact basins.[28] These anomalies greatly influence the orbit of spacecraft about the Moon, and an accurate gravitational model is necessary in the planning of both manned and unmanned missions. The mascons are in part due to the presence of dense mare basaltic lava flows that fill some of the impact basins. However, lava flows by themselves can not explain the entirety of the gravitational signature, and uplift of the crust-mantle interface is required as well. Based on Lunar Prospector gravitational models, it has been suggested that some mascons exist that do not show evidence for mare basaltic volcanism.[29] The huge expanse of mare basaltic volcanism associated with Oceanus Procellarum does not possess a positive gravitational anomaly. Image File history File links MoonLP150Q_grav_150_j2. ... Image File history File links MoonLP150Q_grav_150_j2. ... A mass concentration or mascon is a region of a planet or moons crust that contains a large amount of material that is denser than average for that body. ... Tycho crater on Earths moon. ... NASAs Lunar Prospector The Lunar Prospector mission was the third selected by NASA for full development and construction as part of the Discovery Program. ... The Ocean of Storms of the Moon. ...


Magnetic field

Total magnetic field strength at the surface of the Moon as derived from the Lunar Prospector electron reflectometer experiment

The Moon has an external magnetic field of the order of one to a hundred nanotesla—more than 100 times smaller than the Earth's, which is 30-60 microtesla. Other major differences are that the Moon does not currently have a dipolar magnetic field (as would be generated by a geodynamo in its core), and the magnetizations that are present are almost entirely crustal in origin.[30] One hypothesis holds that the crustal magnetizations were acquired early in lunar history when a geodynamo was still operating. The small size of the lunar core, however, is a potential obstacle to this theory. Alternatively, it is possible that on an airless body such as the Moon, transient magnetic fields could be generated during large impact events. In support of this, it has been noted that the largest crustal magnetizations appear to be located near the antipodes of the giant impact basins. It has been proposed that such a phenomenon could result from the free expansion of an impact generated plasma cloud around the Moon in the presence of an ambient magnetic field.[31] Total magnetic field strength at the surface of the Moon as derived from the Lunar Prospector electron reflectometer experiment. ... Image File history File links Moon_LP_ER_magnetic_field. ... Image File history File links Moon_LP_ER_magnetic_field. ... NASAs Lunar Prospector The Lunar Prospector mission was the third selected by NASA for full development and construction as part of the Discovery Program. ... Magnetic field lines shown by iron filings Magnetostatics Electrodynamics Electrical Network Tensors in Relativity This box:      In physics, the magnetic field is a field that permeates space and which exerts a magnetic force on moving electric charges and magnetic dipoles. ... SI unit. ... The magnetosphere shields the surface of the Earth from the charged particles of the solar wind. ... The Earths magnetic field, which is approximately a dipole. ... The cause of Earths magnetic field (the surface magnetic field) is not known for certain, but is possibly explained by dynamo theory. ... This map shows the antipodes of each point on the Earths surface – the points where the blue and pink overlap are land antipodes. ...


Atmosphere

The Moon has an atmosphere so thin as to be almost negligible, with a total atmospheric mass of less than 104 kg.[32] One source of its atmosphere is outgassing—the release of gases such as radon that originate by radioactive decay processes within the crust and mantle. Another important source is generated through the process of sputtering, which involves the bombardment of micrometeorites, solar wind ions, electrons, and sunlight.[6] Gases that are released by sputtering can either reimplant into the regolith as a result of the Moon's gravity, or can be lost to space either by solar radiation pressure or by being swept away by the solar wind magnetic field if they are ionised. The elements sodium (Na) and potassium (K) have been detected using earth-based spectroscopic methods, whereas the element radon–222 (222Ra) and polonium-210 (210Po) have been inferred from data obtained from the Lunar Prospector alpha particle spectrometer.[33] Argon–40 (40Ar), helium-4 (4He), oxygen (O2) and/or methane (CH4), nitrogen (N2) and/or carbon monoxide (CO), and carbon dioxide (CO2) were detected by in-situ detectors placed by the Apollo astronauts.[34] The atmosphere of the Moon is very tenuous and insignificant in comparison to that of the Earth. ... Outgassing (sometimes called Offgassing, particularly when in reference to indoor air quality) is the slow release of a gas that was trapped, frozen, absorbed or adsorbed in some material. ... For other uses, see Radon (disambiguation). ... Radioactive decay is the process in which an unstable atomic nucleus loses energy by emitting radiation in the form of particles or electromagnetic waves. ... Sputtering is a physical vapor deposition, PVD process whereby atoms in a solid target material are ejected into the gas phase due to bombardment of the material by energetic ions. ... Regolith (Greek: blanket rock) is a layer of loose, heterogeneous material covering solid rock. ... For sodium in the diet, see Edible salt. ... General Name, symbol, number potassium, K, 19 Chemical series alkali metals Group, period, block 1, 4, s Appearance silvery white Standard atomic weight 39. ... For other uses, see Radon (disambiguation). ... Polonium-210 is the most readily available isotope of Polonium. ... NASAs Lunar Prospector The Lunar Prospector mission was the third selected by NASA for full development and construction as part of the Discovery Program. ... An alpha particle is deflected by a magnetic field Alpha radiation consists of helium-4 nuclei and is readily stopped by a sheet of paper. ... General Name, symbol, number argon, Ar, 18 Chemical series noble gases Group, period, block 18, 3, p Appearance colorless Standard atomic weight 39. ... Helium-4 is a non-radioactive and light isotope of helium. ... General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) pale blue (liquid) Standard atomic weight 15. ... Methane is a chemical compound with the molecular formula . ... General Name, symbol, number nitrogen, N, 7 Chemical series nonmetals Group, period, block 15, 2, p Appearance colorless gas Standard atomic weight 14. ... Carbon monoxide, with the chemical formula CO, is a colorless, odorless, and tasteless gas. ... Carbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ...


Origin and geologic evolution

Formation

Several mechanisms have been suggested for the Moon's formation. Early speculation proposed that the Moon broke off from the Earth's crust because of centrifugal forces, leaving a basin (presumed to be the Pacific Ocean) behind as a scar.[35] This fission concept, however, requires too great an initial spin of the Earth. Furthermore, it would have resulted in an orbit following Earth's equatorial plane, which is not the case. Others speculated that the Moon formed elsewhere and was captured into Earth's orbit.[36] However, the conditions required for this capture mechanism to work (such as an extended atmosphere of the Earth for dissipating energy) are improbable. The coformation hypothesis posits that the Earth and the Moon formed together at the same time and place from the primordial accretion disk. In this hypothesis, the Moon formed from material surrounding the proto-Earth, similar to the formation of the planets around the Sun. Some suggest that this hypothesis fails to adequately explain the depletion of metallic iron in the Moon. A major deficiency with all of these hypotheses is that they cannot easily account for the high angular momentum of the Earth–Moon system.[37] Centrifugal force (from Latin centrum centre and fugere to flee) is a term which may refer to two different forces which are related to rotation. ... An accretion disc (or accretion disk) is a structure formed by material falling into a gravitational source. ... This gyroscope remains upright while spinning due to its angular momentum. ...


Today, the giant impact hypothesis for forming the Earth–Moon system is widely accepted by the scientific community. In this hypothesis, the impact of a Mars-sized body (Theia) on the proto-Earth is postulated to have put enough material into circumterrestrial orbit to form the Moon.[8] Given that planetary bodies are believed to have formed by the hierarchical accretion of smaller bodies to larger ones, giant impact events such as this are thought to have affected most planets. Computer simulations modelling this impact are consistent with measurements of the angular momentum of the Earth–Moon system, as well as the small size of the lunar core.[38] Unresolved questions regarding this theory have to do with determining the relative sizes of the proto-Earth and impactor, and with determining how much material from the proto-Earth and impactor ended up in the Moon. The formation of the Moon is believed to have occurred 4.527 ± 0.010 billion years ago, about 30–50 million years after the origin of the solar system.[39] The Big Splash redirects here. ... The Big Splash redirects here. ...


Lunar magma ocean

As a result of the large amount of energy liberated during both the giant impact event and the subsequent reaccretion of material in Earth orbit, it is commonly believed that a large portion of the Moon was once initially molten. The molten outer portion of the Moon at this time is referred to as a magma ocean, and estimates for its depth range from about 500 km to the entire radius of the Moon.[13] This article, which relates to the Moon, is a stub. ...


As the magma ocean cooled, it fractionally crystallised and differentiated, giving rise to a geochemically distinct crust and mantle. The mantle is inferred to have formed largely by the precipitation and sinking of the minerals olivine, clinopyroxene, and orthopyroxene. After about three-quarters of magma ocean crystallisation was complete, the mineral anorthite is inferred to have precipitated and floated to the surface because of its low density, forming the crust.[13] In chemistry, Fractional Crystallization is a method of refining substances based on differences in soluability. ... In cosmogony, planetary differentiation is a process by which the denser portions of a planet will sink to the center; while less dense materials rise to the surface. ... The mineral olivine (also called chrysolite and, when gem-quality, peridot) is a magnesium iron silicate with the formula (Mg,Fe)2SiO4. ... Figure 1:Mantle-peridotite xenolith with green peridot olivine and black pyroxene crystals from San Carlos Indian Reservation, Gila Co. ... Figure 1:Mantle-peridotite xenolith with green peridot olivine and black pyroxene crystals from San Carlos Indian Reservation, Gila Co. ... Anorthite is one of the plagioclase feldspars, an important group of minerals abundant in the Earths crust. ...


The final liquids to crystallise from the magma ocean would have been initially sandwiched between the crust and mantle, and would have contained a high abundance of incompatible and heat-producing elements. This geochemical component is referred to by the acronym KREEP, for potassium (K), rare earth elements (REE), and phosphorus (P), and appears to be concentrated within the Procellarum KREEP Terrane, which is a small geologic province that encompasses most of Oceanus Procellarum and Mare Imbrium on the near side of the Moon.[1] KREEP stands for potassium (atomic symbol K), rare earth elements (REE), and phosphorus (P). ... General Name, symbol, number potassium, K, 19 Chemical series alkali metals Group, period, block 1, 4, s Appearance silvery white Standard atomic weight 39. ... de;Metalle der Seltenen Erden Categories: Stub | Chemical element groups ... General Name, symbol, number phosphorus, P, 15 Chemical series nonmetals Group, period, block 15, 3, p Appearance waxy white/ red/ black/ colorless Standard atomic weight 30. ... This article, which relates to the Moon, is a stub. ... The Ocean of Storms of the Moon. ... Oblique view of Mare Imbrium looking south towards Copernicus crater. ...


Geologic evolution

See also: Geology of the Moon

A large portion of the Moon's post–magma-ocean geologic evolution was dominated by impact cratering. The lunar geologic timescale is largely divided in time on the basis of prominent basin-forming impact events, such as Nectaris, Imbrium, and Orientale. These impact structures are characterised by multiple rings of uplifted material, and are typically hundreds to thousands of kilometres in diameter. Each multi-ring basin is associated with a broad apron of ejecta deposits that forms a regional stratigraphic horizon. While only a few multi-ring basins have been definitively dated, they are useful for assigning relative ages on the basis of stratigraphic grounds. The continuous effects of impact cratering are responsible for forming the regolith. Exploring Shorty crater during the Apollo 17 mission to the Moon. ... The lunar geologic timescale (or perhaps more properly the selenologic timescale) divides the history of Earths Moon into six generally recognized geologic periods: Copernician Period : 1100 MY to present Eratosthenian Period : 3200 MY to 1100 MY Upper Imbrian Epoch : 3800 MY to 3200 MY Lower Imbrian Epoch : 3850 MY... The Nectarian Period of the lunar geologic timescale runs from 3920 million years ago to 3850 million years ago. ... In the Lunar geologic timescale, the Lower Imbrian epoch occurred between 3850 million years ago to about 3800 million years ago. ... 1967 photograph made by NASAs Lunar Orbiter 4 Like a target ring bulls-eye, the lunar mare Mare Orientale (the eastern sea) is one of the most striking large scale lunar features. ... Stratigraphy, a branch of geology, studies rock layers and layering (stratification). ... Regolith (Greek: blanket rock) is a layer of loose, heterogeneous material covering solid rock. ...


The other major geologic process that affected the Moon's surface was mare volcanism. The enhancement of heat-producing elements within the Procellarum KREEP Terrane is thought to have caused the underlying mantle to heat up, and eventually, to partially melt. A portion of these magmas rose to the surface and erupted, accounting for the high concentration of mare basalts on the near side of the Moon.[13] Most of the Moon's mare basalts erupted during the Imbrian period in this geologic province 3.0–3.5 billion years ago. Nevertheless, some dated samples are as old as 4.2 billion years,[40] and the youngest eruptions, based on the method of crater counting, are believed to have occurred only 1.2 billion years ago.[41] Lunar nearside with major maria and craters labeled A global albedo map of the Moon obtained from the Clementine missionThe dark regions are the lunar maria, whereas the lighter regions are the highlands. ... This article, which relates to the Moon, is a stub. ... Lunar nearside with major maria and craters labeled A global albedo map of the Moon obtained from the Clementine missionThe dark regions are the lunar maria, whereas the lighter regions are the highlands. ... This article, which relates to the Moon, is a stub. ...


There has been controversy over whether features on the Moon's surface undergo changes over time. Some observers have claimed that craters either appeared or disappeared, or that other forms of transient phenomena had occurred. Today, many of these claims are thought to be illusory, resulting from observation under different lighting conditions, poor astronomical seeing, or the inadequacy of earlier drawings. Nevertheless, it is known that the phenomenon of outgassing does occasionally occur, and these events could be responsible for a minor percentage of the reported lunar transient phenomena. Recently, it has been suggested that a roughly 3 km diameter region of the lunar surface was modified by a gas release event about a million years ago.[42][43] Schematic diagram illustrating how optical wavefronts from a distant star may be perturbed by a turbulent layer in the atmosphere. ... Outgassing (sometimes called Offgassing, particularly when in reference to indoor air quality) is the slow release of a gas that was trapped, frozen, absorbed or adsorbed in some material. ... This map, based on a survey of 300 TLPs by Barbara Middlehurst and Patrick Moore, shows the approximate distribution of observed events. ...


Moon rocks

Main article: Moon rocks

Moon rocks fall into two main categories, based on whether they underlie the lunar highlands (terrae) or the maria. The lunar highlands rocks are composed of three suites: the ferroan anorthosite suite, the magnesian suite, and the alkali suite (some consider the alkali suite to be a subset of the mg-suite). The ferroan anorthosite suite rocks are composed almost exclusively of the mineral anorthite (a calic plagioclase feldspar), and are believed to represent plagioclase flotation cumulates of the lunar magma ocean. The ferroan anorthosites have been dated using radiometric methods to have formed about 4.4 billion years ago.[40][41] Genesis Rock returned by the Apollo 15 mission. ... Anorthite is one of the plagioclase feldspars, an important group of minerals abundant in the Earths crust. ... Lunar Ferroan Anorthosite #60025 (Plagioclase Feldspar). ...


The mg- and alkali-suite rocks are predominantly mafic plutonic rocks. Typical rocks are dunites, troctolites, gabbros, alkali anorthosites, and more rarely, granite. In contrast to the ferroan anorthosite suite, these rocks all have relatively high Mg/Fe ratios in their mafic minerals. In general, these rocks represent intrusions into the already-formed highlands crust (though a few rare samples appear to represent extrusive lavas), and they have been dated to have formed about 4.4–3.9 billion years ago. Many of these rocks have high abundances of, or are genetically related to, the geochemical component KREEP. Dunite is an igneous, plutonic rock, of ultramafic composition, with coarse grained or phaneritic texture. ... Troctolite is a rare ultramafic intrusive rock type. ... Gabbro specimen. ... Anorthosite is a phaneritic, intrusive igneous rock characterized by a predominance of plagioclase feldspar (90-100%), and a minimal mafic component (0-10%). Pyroxene, ilmenite, magnetite, and olivine are the mafic minerals most commonly present. ... For other uses, see granite (disambiguation). ... KREEP stands for potassium (atomic symbol K), rare earth elements (REE), and phosphorus (P). ...


The lunar maria consist entirely of mare basalts. While similar to terrestrial basalts, they have much higher abundances of iron, are completely lacking in hydrous alteration products, and have a large range of titanium abundances.[44][45]


Astronauts reported that the dust from the surface felt like snow and smelled like spent gunpowder.[46] The dust is mostly made of silicon dioxide glass (SiO2), most likely created from the meteors that have crashed into the Moon's surface. It also contains calcium and magnesium. Smokeless powder Gunpowder is a pyrotechnic composition, an explosive mixture of sulfur, charcoal and potassium nitrate that burns rapidly, producing volumes of hot gas which can be used as a propellant in firearms and fireworks. ... R-phrases R42 R43 R49 S-phrases S22 S36 S37 S45 S53 Flash point non-flammable Supplementary data page Structure and properties n, εr, etc. ... For other uses, see Calcium (disambiguation). ... General Name, symbol, number magnesium, Mg, 12 Chemical series alkaline earth metals Group, period, block 2, 3, s Appearance silvery white solid at room temp Standard atomic weight 24. ...


Orbit and relationship to Earth

Main article: Orbit of the Moon
Earth as viewed from the Moon during the Apollo 8 mission, Christmas Eve, 1968
Earth as viewed from the Moon during the Apollo 8 mission, Christmas Eve, 1968

The Moon makes a complete orbit around the Earth with respect to the fixed stars (its sidereal period) about once every 27.3 days. However, since the Earth is moving in its orbit about the Sun at the same time, it takes slightly longer for the Moon to show its same phase to Earth, which is about 29.5 days (its synodic period).[8] Unlike most satellites of other planets, the Moon orbits near the ecliptic and not the Earth's equatorial plane. It is the largest moon in the solar system relative to the size of its planet. (Charon is larger relative to the dwarf planet Pluto.) The natural satellites orbiting other planets are called "moons", after Earth's Moon. The orbit of the Moon around the Earth is completed in approximately 27. ... Download high resolution version (2400x2400, 303 KB) Description Taken by Apollo 8 crewmember Bill Anders on December 24, 1968, showing the Earth rising above the lunar surface. ... Download high resolution version (2400x2400, 303 KB) Description Taken by Apollo 8 crewmember Bill Anders on December 24, 1968, showing the Earth rising above the lunar surface. ... This article is about Earth as a planet. ... Apollo 8 was the second successful manned mission of the Apollo space program, in which Commander Frank Borman, Command Module Pilot James Lovell and Lunar Module Pilot William Anders became the first humans to orbit around the Moon. ... The Christmas Eve (1904-05), watercolor painting by the Swedish painter Carl Larsson (1853-1919) Christmas Eve, the evening of December 24th, the preceding day or vigil before Christmas Day, is treated to a greater or a lesser extent in most Christian societies as part of the Christmas season. ... The orbital period is the time it takes a planet (or another object) to make one full orbit. ... Lunar phase refers to the appearance of the illuminated portion of the Moon as seen by an observer, usually on Earth. ... The orbital period is the time it takes a planet (or another object) to make one full orbit. ... The plane of the ecliptic is well seen in this picture from the 1994 lunar prospecting Clementine spacecraft. ... In astronomy and navigation, the celestial sphere is an imaginary rotating sphere of gigantic radius, concentric with the Earth. ... Charon (shair-É™n or kair-É™n (key), IPA , Greek Χάρων), discovered in 1978, is, depending on the definition employed, either the largest moon of Pluto or one member of a double dwarf planet with Pluto being the other member. ... Artists impression of Pluto (background) and Charon (foreground). ... For other uses, see Pluto (disambiguation). ... A natural satellite is an object that orbits a planet or other body larger than itself and which is not man-made. ...


Most of the tidal effects seen on the Earth are caused by the Moon's gravitational pull, with the Sun making only a small contribution. Tidal effects result in an increase of the mean Earth-Moon distance of about 3.8 m per century, or 3.8 cm per year.[47] As a result of the conservation of angular momentum, the increasing semimajor axis of the Moon is accompanied by a gradual slowing of the Earth's rotation by about 0.002 seconds per day per century.[48] In physics, angular momentum intuitively measures how much the linear momentum is directed around a certain point called the origin; the moment of momentum. ...


The Earth–Moon system is sometimes considered to be a double planet rather than a planet–moon system. This is due to the exceptionally large size of the Moon relative to its host planet; the Moon is a quarter the diameter of Earth and 1/81 its mass. However, this definition is criticised by some, since the common centre of mass of the system (the barycentre) is located about 1700 km beneath the surface of the Earth, or about a quarter of the Earth's radius. The surface of the Moon is less than 1/10th that of the Earth, and only about a quarter the size of the Earth's land area (or about as large as Russia, Canada, and the U.S. combined). Pluto and Charon are sometimes informally considered to be a double (dwarf) planet. ... The barycenter (from the Greek βαρύκεντρον) is the center of mass of two or more bodies which are orbiting each other, and is the point around which both of them orbit. ...


In 1997, the asteroid 3753 Cruithne was found to have an unusual Earth-associated horseshoe orbit. However, astronomers do not consider it to be a second moon of Earth, and its orbit is not stable in the long term.[49] Three other near-Earth asteroids, (54509) 2000 PH5, (85770) 1998 UP1 and 2002 AA29, which exist in orbits similar to Cruithne's, have since been discovered.[50] 3753 Cruithne (pronounced , Modern Irish ) is an asteroid in orbit around the Sun. ... A horseshoe orbit is the type of orbit you get when you observe an object from another nearly co-orbital object, such as a planet. ... Computer model of the Apollo Asteroid 6489 Golevka Near-Earth asteroids (NEAs) are asteroids whose orbits are close to Earths orbit. ... Asteroid 2002 AA29 (also written 2002 AA29) is a near-Earth asteroid discovered in January 2001 by the LINEAR asteroid survey. ...

The relative sizes and separation of the Earth–Moon system along with light’s time-of-flight are shown to scale above. Surface-to-surface transit time of the beam from the Earth to the Moon at its mean orbital distance is 1.255 seconds. The light beam helps provide the sense of scale of the Earth-Moon system relative to the Sun, which is 8.28 light-minutes away (photosphere to Earth surface).

Download high resolution version (1024x92, 4 KB)Self-made File links There are no pages that link to this file. ... Download high resolution version (1024x92, 4 KB)Self-made File links There are no pages that link to this file. ...

Ocean tides

Earth’s ocean tides are initiated by the tidal force (a gradient in intensity) of Moon’s gravity and are magnified by a host of effects in Earth’s oceans. The gravitational tidal force arises because the side of Earth facing the Moon (nearest it) is attracted more strongly by the Moon’s gravity than is the center of the Earth and—even less so—the Earth’s far side. The gravitational tide stretches the Earth’s oceans into an ellipse—with the Earth in the center. The effect takes the form of two bulges—elevated sea level—relative to the Earth: one nearest the Moon and one farthest from it. Since these two bulges rotate around the Earth once a day as it spins on its axis, ocean water is continuously rushing towards the ever-moving bulges. The effects of the two bulges and the massive ocean currents chasing them are magnified by an interplay of other effects; namely frictional coupling of water to Earth’s rotation through the ocean floors, inertia of water’s movement, ocean basins that get shallower near land, and oscillations between different ocean basins. The magnifying effect is a bit like water sloshing high up the sloped end of a bathtub after a relatively small disturbance of one’s body in the deep part of the tub. This article is about tides in the Earths oceans. ... Comet Shoemaker-Levy 9 after breaking up under the influence of Jupiters tidal forces. ...


Gravitational coupling between the Moon and the oceans affects the orbit of the Moon. From the Moon's point of view, the tidal bulges are carried ahead by the rotation of the Earth, so that they don't point directly toward the Moon. The gravitational coupling drains kinetic energy and angular momentum from the Earth’s rotation. In turn, angular momentum is added to the Moon's orbit. Somewhat counterintuitively, this moves the Moon to a higher orbit with a longer period. This results in a 3.8 cm yearly increase in the distance between the two bodies.[51] The Moon will continue to move slowly away from the Earth until the tidal effects between the two are no longer of significance, whereupon the Moon's orbit will stabilize. The orbit of the Moon around the Earth is completed in approximately 27. ... The cars of a roller coaster reach their maximum kinetic energy when at the bottom of their path. ... This gyroscope remains upright while spinning due to its angular momentum. ...


Eclipses

Main articles: Solar eclipse and Lunar eclipse
The 1999 solar eclipse
The 1999 solar eclipse
The 3 March 2007 lunar eclipse

Eclipses can occur only when the Sun, Earth, and Moon are all in a straight line. Solar eclipses occur near a new moon, when the Moon is between the Sun and Earth. In contrast, lunar eclipses occur near a full moon, when the Earth is between the Sun and Moon. Photo taken during the 1999 eclipse. ... Time lapse movie of the 3 March 2007 lunar eclipse A lunar eclipse occurs whenever the Moon passes through some portion of the Earth’s shadow. ... Image File history File linksMetadata Download high-resolution version (3543x3489, 2027 KB) Summary Description: Solar eclipse 1999 in France view 4 Additional noise reduction performed by Diliff. ... Image File history File linksMetadata Download high-resolution version (3543x3489, 2027 KB) Summary Description: Solar eclipse 1999 in France view 4 Additional noise reduction performed by Diliff. ... Image File history File links Metadata Size of this preview: 699 × 599 pixelsFull resolution (1081 × 927 pixel, file size: 234 KB, MIME type: image/jpeg) Eclipse of the Moon on 3rd March 2007, shortly before the start of totality. ... Image File history File links Metadata Size of this preview: 699 × 599 pixelsFull resolution (1081 × 927 pixel, file size: 234 KB, MIME type: image/jpeg) Eclipse of the Moon on 3rd March 2007, shortly before the start of totality. ... Time lapse movie of the 3 March 2007 lunar eclipse A lunar eclipse occurs whenever the Moon passes through some portion of the Earth’s shadow. ... Photo taken during the 1999 eclipse. ... The lunar phase depends on the Moons position in orbit around Earth. ... Time lapse movie of the 3 March 2007 lunar eclipse A lunar eclipse occurs whenever the Moon passes through some portion of the Earth’s shadow. ... For other uses, see Full Moon. ...


Because the Moon's orbit around the Earth is inclined by about 5° with respect to the orbit of the 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.[52] The plane of the ecliptic is well seen in this picture from the 1994 lunar prospecting Clementine spacecraft. ...


The periodicity and recurrence of eclipses of the Sun by the Moon, and of the Moon by the Earth, is described by the saros cycle, which has a period of approximately 6,585.3 days (18 years 11 days 8 hours).[53] A Saros cycle is a period of 6585 + 1/3 days (approximately 18 years 10 days and 8 hours) which can be used to predict eclipses of the sun and the moon. ...


The angular diameters of the Moon and the Sun as seen from Earth overlap in their variation, so that both total and annular solar eclipses are possible.[54] In a total eclipse, the Moon completely covers the disc of the Sun and the solar corona becomes visible to the naked eye. Since the distance between the Moon and the Earth is very slightly increasing over time, the angular diameter of the Moon is decreasing. This means that hundreds of millions of years ago the Moon could always completely cover the Sun on solar eclipses so that no annular eclipses were possible. Likewise, about 600 million years from now (assuming that the angular diameter of the Sun will not change), the Moon will no longer cover the Sun completely and only annular eclipses will occur.[52] For the 1995 film, see Total Eclipse (film). ... For Solar Eclipse, the alien friend of the rubber doll Betty Spaghetty, see Betty Spaghetty Photo taken by John Walker during the Zambia 2001 eclipse A solar eclipse occurs when the Sun, Moon and Earth are on a single line with the Moon in the middle. ... This article is about the astronomical term. ... The naked eye is a figure of speech referring to human visual perception that is unaided by enhancing equipment, such as a telescope or binoculars. ...


A phenomenon related to eclipse is occultation. The Moon is continuously blocking our view of the sky by a 1/2 degree-wide circular area. When a bright star or planet passes behind the Moon it is occulted or hidden from view. A solar eclipse is an occultation of the Sun. Because the Moon is close to Earth, occultations of individual stars are not visible everywhere, nor at the same time. Because of the precession of the lunar orbit, each year different stars are occulted.[55] In this July, 1997 still frame captured from video, the bright star Aldebaran has just reappeared on the dark limb of the waning crescent moon in this predawn occultation. ...


The most recent total lunar eclipse took place on August 28, 2007. It was visible from the Americas, the Pacific Ocean, eastern Asia and Oceania. The most recent solar eclipse took place on September 11, 2007, visible from southern South America and parts of Antarctica. The next total solar eclipse, on August 1, 2008, will have a path of totality beginning in northern Canada and passing through Russia and China.[56] is the 240th day of the year (241st in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 254th day of the year (255th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 213th day of the year (214th in leap years) in the Gregorian calendar. ... 2008 (MMVIII) will be a leap year starting on Tuesday of the Anno Domini (common) era, in accordance with the Gregorian calendar. ...


Observation

See also: Lunar phase, Earthshine, and Observing the Moon

During its brightest phase, at "full moon", the Moon has an apparent magnitude of about −12.6. By comparison, the Sun has an apparent magnitude of −26.8. When the Moon is in a quarter phase, its brightness is not half of a full moon, but only about a tenth. This is because the lunar surface is not a perfect Lambertian reflector. When the Moon is full the opposition effect makes it appear brighter, but away from full there are shadows projected onto the surface which diminish the amount of reflected light. Lunar phase refers to the appearance of the illuminated portion of the Moon as seen by an observer, usually on Earth. ... Leonardo da Vincis sketch of crescent Moon with earthshine as part of his Codex Leicester, written between 1506 and 1510. ... // Contrary to popular belief, the Moon should not be viewed at its full phase. ... The apparent magnitude (m) of a star, planet or other celestial body is a measure of its apparent brightness as seen by an observer on Earth. ... If a surface exhibits Lambertian reflectance, light falling on it is scattered such that the amount of light an observer sees, the surface luminance, is the same regardless of their angle of view. ... It has been suggested that this article or section be merged with Opposition spike. ...


The Moon appears larger when close to the horizon. This is a purely psychological effect (see Moon illusion). It is actually about 1.5% smaller when the Moon is near the horizon than when it is high in the sky (because it is farther away by up to one Earth radius). The Moon illusion is an optical illusion in which the Moon appears larger near the horizon than it does while higher up in the sky. ...


The moon appears as a relatively bright object in the sky, in spite of its low albedo. The Moon is about the poorest reflector in the solar system and reflects only about 7% of the light incident upon it (about the same proportion as is reflected by a lump of coal).[57] Color constancy in the visual system recalibrates the relations between the colours of an object and its surroundings, and since the surrounding sky is comparatively dark the sunlit Moon is perceived as a bright object. For other uses, see Albedo (disambiguation). ... A reflector can mean one of several things: a reflecting telescope a device or a part of an antenna that reflects radio waves a device that causes reflection, for example, a mirror or a retroreflector a 1981 album by Pablo Cruise In LAPACK the term reflector with the types block... This article is about the Solar System. ... Color constancy is an example of subjective constancy and a feature of the human color-perception system which ensures that the perceived color of objects remains relatively constant under varying illumination conditions. ... The visual system is the part of the nervous system which allows organisms to see. ...

A halo around the Moon
A halo around the Moon

The highest altitude of the Moon on a day varies and has nearly the same limits as the Sun. It also depends on the Earth season and lunar phase, with the full moon being highest in winter. Moreover, the 18.6 year nodes cycle has also influence on it, as when the ascending node of the lunar orbit is in the vernal equinox, the lunar declination can go as far as 28° each month (which happened most recently in 2006). This results that the Moon can go overhead on latitudes till 28 degrees (e.g. Florida, Canary Islands or in the southern hemisphere Brisbane). Slightly more than 9 years later (next time in 2015) the declination reaches only 18° N or S each month. 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 boat Moon.[58] Image File history File links Download high resolution version (1600x1600, 54 KB) Halo around moon. ... Image File history File links Download high resolution version (1600x1600, 54 KB) Halo around moon. ... It has been suggested that Moon dog be merged into this article or section. ... In astronomy and surveying, altitude (sometimes called elevation) is one of the two coordinates of the horizontal coordinate system, and refers to the vertical angle from the horizon. ... This article is about the U.S. State of Florida. ... Anthem: Arrorró Capital Las Palmas de Gran Canaria and Santa Cruz de Tenerife Official language(s) Spanish Area  â€“ Total  â€“ % of Spain Ranked 13th  7,447 km²  1. ... For other uses, see Brisbane (disambiguation). ...


Like the Sun, the Moon can give rise to atmospheric effects, including a 22° halo ring, and the smaller coronal rings seen more often through thin clouds. For more information on how the Moon appears in Earth's sky, see lunar phase. It has been suggested that Moon dog be merged into this article or section. ... A lunar corona In meteorology, a corona is produced by the diffraction of light from either the Sun or the Moon through a cloud of water droplets. ... Lunar phase refers to the appearance of the illuminated portion of the Moon as seen by an observer, usually on Earth. ...


Exploration

See also: Robotic exploration of the Moon, Future lunar missions, and Colonization of the Moon

The first leap in lunar observation was prompted by the invention of the telescope. Galileo Galilei made good use of this new instrument and observed mountains and craters on the Moon's surface. To meet Wikipedias quality standards, this article or section may require cleanup. ... This article is about the series of human spaceflight missions. ... Still frame from the video transmission of Neil Armstrong stepping onto the surface of the Moon on 20 July 1969. ... Pioneer 0 (USA, 1958) - failure - orbiter Pioneer 1 (USA, 1958) - failure - orbiter Pioneer 3 (USA, 1958) - failure - flyby Luna 1 (Soviet Union, 1959) - success - flyby Pioneer 4 (USA, 1959) - partial success - flyby Luna 2 (Soviet Union, 1959) - success - impactor Luna 3 (Soviet Union, 1959) - success - flyby Ranger 3 (USA, 1962... It has been suggested that this article or section be merged into Exploration of the Moon. ... Lunar outpost redirects here. ... Galileo redirects here. ...


The Cold War-inspired space race between the Soviet Union and the U.S. led to an acceleration of interest in the Moon. Unmanned probes, both flyby and impact/lander missions, were sent almost as soon as launcher capabilities would allow. The Soviet Union's Luna program was the first to reach the Moon with unmanned spacecraft. The first man-made object to escape Earth's gravity and pass near the Moon was Luna 1, the first man-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.[8] Moon samples have been brought back to Earth by three Luna missions (Luna 16, 20, and 24) and the Apollo missions 11 to 17 (except Apollo 13, which aborted its planned lunar landing). For other uses, see Cold War (disambiguation). ... For other uses, see Space Race (disambiguation). ... The Luna programme (occasionally called Lunik) was a series of unmanned space missions sent to the Moon by the Soviet Union between 1959 and 1976. ... The Space Shuttle Discovery as seen from the International Space Station. ... Luna 1 is the first spacecraft to reach the vicinity of the Moon and the first of the Luna programme of Soviet automatic interplanetary stations successfully launched in the direction of the Moon. ... Luna 2 (E-1A series) was the second of the Soviet Unions Luna program spacecraft launched in the direction of the Moon. ... Luna 3 (E-3 series) was the third spacecraft sent successfully to the moon and was an early triumph in the human exploration of outer space. ... Luna 9 (E-6 series), also known as Lunik 9 (internal name E-6 N. 13), was an unmanned space mission of the Soviet Unions Luna program. ... Luna 10 was an unmanned space mission of the Luna program, also called Lunik 10. ... Luna 16 (Ye-8-5 series) was an unmanned space mission of the Luna program, also called Lunik 16. ... Luna 20 (Ye-8-5 series) was an unmanned space mission of the Luna program, also called Lunik 20. ... Luna 24 was an unmanned space mission of the Luna program, also called Lunik 24. ... Original crew photo. ...

First images of the far side of the Moon taken from Luna 3

The landing of the first humans on the Moon in 1969 is seen as the culmination of the space race.[59] 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. The American Moon landing and return was enabled by considerable technological advances, in domains such as ablation chemistry and atmospheric re-entry technology, in the early 1960s. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Far side of the Moon. ... Luna 3 (E-3 series) was the third spacecraft sent successfully to the moon and was an early triumph in the human exploration of outer space. ... This article is about the former American astronaut. ... This article covers the Apollo 11 mission itself. ... is the 202nd day of the year (203rd in leap years) in the Gregorian calendar. ... Also: 1969 (number) 1969 (movie) 1969 (Stargate SG-1) episode. ... Still frame from the video transmission of Neil Armstrong stepping onto the surface of the Moon on 20 July 1969. ... Ablation is defined as the removal of material from the surface of an object by vaporization, chipping, or other erosive processes. ... Atmospheric entry is the transition from the vacuum of space to the atmosphere of any planet or other celestial body. ...


Scientific instrument packages were installed on the lunar surface during all of the Apollo missions. Long-lived ALSEP stations (Apollo lunar surface experiment package) were installed at the Apollo 12, 14, 15, 16, and 17 landing sites, whereas a temporary station referred to as EASEP (Early Apollo Scientific Experiments Package) was installed during the Apollo 11 mission. The ALSEP stations contained, among others, heat flow probes, seismometers, magnetometers, and corner-cube retroreflectors. Transmission of data to Earth was terminated on 30 September 1977 because of budgetary considerations[60][61]. Since the lunar laser ranging (LLR) corner-cube arrays are passive instruments, they are still being used. Ranging to the LLR 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.[62] The Apollo Lunar Surface Experiment Package, or ALSEP, was a set of connected scientific instruments left on the Moon when the Apollo program ended. ... Apollo 12 was the sixth manned mission in the Apollo program and the second to land on the Moon. ... Apollo 14 was the eighth manned mission in the Apollo program and the third mission to land on the Moon. ... Apollo 15 was the ninth manned mission in the Apollo program and the fourth mission to land on the Moon. ... Apollo 16 was the tenth manned mission in the Apollo program and the fifth mission to land on the Moon. ... Apollo 17 was the eleventh manned space mission in the NASA Apollo program. ... is the 273rd day of the year (274th in leap years) in the Gregorian calendar. ... Also: 1977 (album) by Ash. ... The Lunar Laser Ranging Experiment from the Apollo 11 mission The ongoing Lunar Laser Ranging Experiment measures the distance between the Earth and the Moon using laser ranging. ...


It is now 34 years, 349 days since Eugene Cernan, as part of the mission Apollo 17, left the surface of the Moon on 14 December 1972 and no one has set foot on it since. Eugene Andrew Cernan (born March 14, 1934) is a retired United States Navy officer and a former NASA astronaut of Czech and Slovak ancestry. ... Apollo 17 was the eleventh manned space mission in the NASA Apollo program. ...

From the mid-1960s to the mid-1970s, there were 65 instances of artificial objects reaching the Moon (both manned and robotic, with ten in 1971 alone), with the last being Luna 24 in 1976. Only 18 of these were controlled moon landings, with nine completing a round trip from Earth and returning samples of moon rocks. The Soviet Union then turned its primary attention to Venus and space stations, and the U.S. to Mars and beyond. In 1990, Japan orbited the Moon with the Hiten spacecraft, becoming the third country to place a spacecraft into lunar orbit. The spacecraft released a smaller probe, Hagormo, in lunar orbit, but the transmitter failed, thereby preventing further scientific use of the mission. Image File history File links Download high resolution version (2700x2700, 2494 KB) Short description: Astronaut Buzz Aldrin on the moon Full description: Astronaut Buzz Aldrin, lunar module pilot, walks on the surface of the Moon near the leg of the Lunar Module (LM) Eagle during the Apollo 11 extravehicular activity... Image File history File links Download high resolution version (2700x2700, 2494 KB) Short description: Astronaut Buzz Aldrin on the moon Full description: Astronaut Buzz Aldrin, lunar module pilot, walks on the surface of the Moon near the leg of the Lunar Module (LM) Eagle during the Apollo 11 extravehicular activity... For other uses, see Astronaut (disambiguation). ... Colonel Buzz Aldrin, Sc. ... This article is about the former American astronaut. ... Still frame from the video transmission of Neil Armstrong stepping onto the surface of the Moon on 20 July 1969. ... Luna 24 was an unmanned space mission of the Luna program, also called Lunik 24. ... The first moon landing by a human was that of American Neil Armstrong, commander of the Apollo 11 mission, accompanied by Buzz Aldrin. ... Genesis Rock returned by the Apollo 15 mission. ... For other uses, see Venus (disambiguation). ... The International Space Station in 2007 A space station is an artificial structure designed for humans to live in outer space. ... Adjectives: Martian Atmosphere Surface pressure: 0. ... Hiten spacecraft The Hiten spacecraft (known before launch as Muses-A), built by the Institute of Space and Aeronautical Science of Japan, was launched on January 24, 1990. ...


In 1994, the U.S. finally returned to the Moon, robotically at least, sending the Joint Defense Department/NASA spacecraft Clementine. 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 by the Lunar Prospector mission in 1998. The neutron spectrometer on Lunar Prospector 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 metres of the regolith within permanently shadowed craters. The European spacecraft Smart 1 was launched September 27, 2003 and was in lunar orbit from November 15, 2004 to September 3, 2006. Clementine was a joint space project between the Ballistic Missile Defense Organization (BMDO, previously the Strategic Defense Initiative Organization, or SDIO) and NASA. The objective of the mission was to test sensors and spacecraft components under extended exposure to the space environment and to make scientific observations of the Moon... Is the ability of a remote sensing device to detect electromagnetic energy in at least two or more individual wavelength intervals ... NASAs Lunar Prospector The Lunar Prospector mission was the third selected by NASA for full development and construction as part of the Discovery Program. ... This article or section does not adequately cite its references or sources. ... Spectrometer A spectrometer is an optical instrument used to measure properties of light over a specific portion of the electromagnetic spectrum, typically used in spectroscopic analysis to identify materials. ... SMART-1 was a Swedish-designed European Space Agency satellite that orbited around the Moon. ... is the 270th day of the year (271st in leap years) in the Gregorian calendar. ... Year 2003 (MMIII) was a common year starting on Wednesday of the Gregorian calendar. ... is the 319th day of the year (320th in leap years) in the Gregorian calendar. ... Year 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... is the 246th day of the year (247th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ...


On January 14, 2004, U.S. President George W. Bush called for a plan to return manned missions to the Moon by 2020 (see Vision for Space Exploration).[63] NASA is now planning for the construction of a permanent outpost at one of the lunar poles.[64] The People's Republic of China has expressed ambitious plans for exploring the Moon and has started the Chang'e program for lunar exploration, successfully launching its first spacecraft, Chang'e-1, on October 24, 2007. [65] India intends to launch several unmanned missions, beginning with Chandrayaan I in February 2008, followed by Chandaryaan II in 2010 or 2011; the latter is slated to include a robotic lunar rover. India also has expressed its hope for a manned mission to the Moon by 2030.[66] The U.S. will launch the Lunar Reconnaissance Orbiter in 2008. Russia also announced to resume its previously frozen project Luna-Glob, consisting of an unmanned lander and orbiter, which is slated to land in 2012.[67] is the 14th day of the year in the Gregorian calendar. ... Year 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... George Walker Bush (born July 6, 1946) is the forty-third and current President of the United States of America, originally inaugurated on January 20, 2001. ... Image from NASA site Two planned configurations for a return to the moon, heavy lift (left) and crew (right) The Vision for Space Exploration is the United States space policy announced on January 14, 2004 by President George W. Bush. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Chang’e 1 (嫦娥一号), a lunar orbiting spacecraft, is part of the first phase of the Chinese Lunar Exploration Program. ... is the 297th day of the year (298th in leap years) in the Gregorian calendar. ... Chandrayaan I (Sanskrit चंद्रयान-1), which literally means Moon Craft, is an unmanned lunar mission by the Indian Space Research Organization. ... Lunar Reconnaissance Orbiter The Lunar Reconnaissance Orbiter (LRO) is an unmanned orbiter planned for launch to the Moon in October 2008 aboard an Atlas V [1]. It is an early element of the implementation of the United States Vision for Space Exploration and its objectives are primarily to support that... Luna-Glob is an unmanned mission to the Moon planned by Russia including an orbiter aswell as a landing module with 12 ground penetrating sensors. ...


The Google Lunar X Prize announced 13 September 2007 hopes to boost and encourage privately funded lunar exploration. The X Prize Foundation is offering anyone 20 million dollars US who can land a robotic rover on the Moon and meet other specified criteria. The original Ansari X Prize was presented on November 6, 2004. ...


On Sept 14, 2007 the Japan Aerospace Exploration Agency launched SELENE a lunar orbiter which is fitted with a High Definition camera and two small satellites. The mission is expected to last one year. [68] The Japan Aerospace Exploration Agency ), or JAXA, is Japans national aerospace agency. ... This article is about the Greek goddess. ... Generally, high-definition refers to an increase in resolution or clarity such as in: High-definition television (HDTV), television formats that have a higher resolution than their contemporary counterparts High-definition video, which is used in HDTV broadcasting, as well as digital film and computer HD video file formats HDV...


Human understanding

See also: The Moon in mythology, Moon in art and literature, Lunar effect, and Artemis
Map of the Moon by Johannes Hevelius (1647)
Map of the Moon by Johannes Hevelius (1647)

The Moon has been the subject of many works of art and literature and the inspiration for countless others. It is a motif in the visual arts, the performing arts, poetry, prose and music. A 5,000-year-old rock carving at Knowth, Ireland may represent the Moon, which would be the earliest depiction discovered.[69] In many prehistoric and ancient cultures, the Moon was thought to be a deity or other supernatural phenomenon, and astrological views of the Moon continue to be propagated today. The Moon has figured in many mythologies, often paired or contrasted with the Sun (see also Solar deity). ... This article is about the Moon as the subject of and inspiration for creative works. ... The lunar effect is the supposed influence of the moon, and its various phases, on human behaviour. ... For other uses, see Artemis (disambiguation). ... Image File history File linksMetadata Download high resolution version (683x624, 446 KB) Subject : map of the moon Author : Johannes Hevelius Date : 1647 File links The following pages link to this file: Johannes Hevelius Metadata This file contains additional information, probably added from the digital camera or scanner used to create... Image File history File linksMetadata Download high resolution version (683x624, 446 KB) Subject : map of the moon Author : Johannes Hevelius Date : 1647 File links The following pages link to this file: Johannes Hevelius Metadata This file contains additional information, probably added from the digital camera or scanner used to create... Johannes Hevelius Johannes Hevelius (Latin), also called Johann Hewelke, Johannes Höwelcke or Johannes Hewel (in German), or Jan Heweliusz (in Polish), (born January 28, 1611 – died January 28, 1687), was a councillor and mayor in Danzig (GdaÅ„sk). ... Knowth is the site of a neolithic passage grave, one of the ancient monuments of the Brú na Bóinne complex in the valley of the River Boyne in Ireland. ... An 18th century drawing of Khoikhoi worshipping the moon In mythology, a lunar deity is a god or goddess associated with or symbolizing the moon: see moon (mythology). ... For other uses, see Supernatural (disambiguation). ... This article needs to be cleaned up to conform to a higher standard of quality. ...


Among the first in the Western world to offer a scientific explanation for the Moon was the Greek philosopher Anaxagoras, who reasoned that the Sun and Moon were both giant spherical rocks, and that the latter reflected the light of the former. His atheistic view of the heavens was one cause for his imprisonment and eventual exile.[70] Anaxagoras Anaxagoras (Greek: Αναξαγόρας, c. ...


In Aristotle's 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. This separation was held to be part of physics for many centuries after.[71] For other uses, see Aristotle (disambiguation). ...

Moon against the Belt of Venus
Moon against the Belt of Venus

By the Middle Ages, before the invention of the telescope, more and more people began to recognise the Moon as a sphere, though they believed that it was "perfectly smooth".[72] 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. Later in the 17th century, Giovanni Battista Riccioli and Francesco Maria Grimaldi drew a map of the Moon and gave many craters the names they still have today. Image File history File links Download high resolution version (1600x1200, 278 KB) Moonrise over red and blue haze, known as the Belt of Venus it is an inverted sunset File links The following pages link to this file: Moon Haze ... Image File history File links Download high resolution version (1600x1200, 278 KB) Moonrise over red and blue haze, known as the Belt of Venus it is an inverted sunset File links The following pages link to this file: Moon Haze ... The Belt of Venus or Venuss Girdle is the Victorian era name for an atmospheric phenomenon seen at sunrise and sunset. ... The Middle Ages formed the middle period in a traditional schematic division of European history into three ages: the classical civilization of Antiquity, the Middle Ages, and modern times, beginning with the Renaissance. ... Galileo redirects here. ... Sidereus Nuncius (usually translated into English as Sidereal Messenger, although Starry Messenger and Sidereal Message are also seen) is a short treatise published in Latin by Galileo Galilei in March 1610. ... Giovanni Battista Riccioli (b. ... Francesco Maria Grimaldi (April 2, 1618 - December 28, 1663) was an Italian mathematician and physicist who taught at the Jesuit college in Bologna. ...

Still from silent film Le Voyage dans la Lune (1902) by Georges Méliès

On maps, the dark parts of the Moon's surface were called maria (singular mare) or seas, and the light parts were called terrae or continents. The possibility that the Moon contains vegetation and is inhabited by selenites was seriously considered by major astronomers even into the first decades of the 19th century. The contrast between the brighter highlands and darker maria create the patterns seen by different cultures as the Man in the Moon, the rabbit and the buffalo, among others. Image of the 1902 film A Voyage to the moon (public domain) This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. ... Image of the 1902 film A Voyage to the moon (public domain) This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. ... Le Voyage dans la lune is a 1902 French science fiction black and white silent film known in its English language release as A Trip to the Moon. ... Georges Méliès (December 8, 1861 – January 21, 1938), full name Marie-Georges-Jean Méliès, was a French filmmaker famous for leading many technical and narrative developments in the earliest cinema. ... For other uses, see Man in the Moon (disambiguation). ...


In 1835, the Great Moon Hoax fooled some people into thinking that there were exotic animals living on the Moon.[73] Almost at the same time however (during 1834–1836), Wilhelm Beer and Johann Heinrich Mädler were publishing their four-volume Mappa Selenographica and the book Der Mond in 1837, which firmly established the conclusion that the Moon has no bodies of water nor any appreciable atmosphere. Great Moon Hoax lithograph of ruby amphitheater for New York Sun, 28 August 1835 (4th article of 6) The Great Moon Hoax was a series of six articles that appeared in the New York Sun beginning on August 25, 1835 about the supposed discovery of life on the Moon. ... Wilhelm Beer Wilhelm Wolff Beer (January 14, 1797 – March 27, 1850) was a banker and astronomer in Berlin, Germany, and brother of Giacomo Meyerbeer. ... J. H. von Mädler. ...


The far side of the Moon remained completely unknown until the Luna 3 probe was launched in 1959, and was extensively mapped by the Lunar Orbiter program in the 1960s. Luna 3 (E-3 series) was the third spacecraft sent successfully to the moon and was an early triumph in the human exploration of outer space. ... Lunar orbiter spacecraft (NASA) The Lunar Orbiter program was a series of five unmanned Lunar orbiter missions launched by the United States in 1966 through 1967 with the purpose of mapping the lunar surface before the Apollo landings. ...


Legal status

Main article: Space law

Although several pennants of the Soviet Union were scattered by Luna 2 in 1959 and by later landing missions, and U.S. flags have been symbolically planted on the Moon, no nation currently claims ownership of any part of the Moon's surface. Russia and the U.S. are party to the Outer Space Treaty, which places the Moon under the same jurisdiction as international waters (res communis). This treaty also restricts the use of the Moon to peaceful purposes, explicitly banning military installations and weapons of mass destruction (including nuclear weapons).[74] To meet Wikipedias quality standards, this article or section may require cleanup. ... Luna 2 (E-1A series) was the second of the Soviet Unions Luna program spacecraft launched in the direction of the Moon. ... Flag ratio: 10:19; nicknames: Stars and Stripes, Old Glory The flag of the United States of America consists of thirteen equal horizontal stripes of red (top and bottom) alternating with white; there is a blue rectangle in the upper hoist-side corner bearing 50 small, white, five-pointed stars... // The Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies also known as the Outer Space Treaty (the Treaty), was opened for signature in the United States, the United Kingdom, and the Soviet Union (the three... The terms international waters or trans-boundary waters apply where any of the following types of bodies of water (or their drainage basins) transcend international boundaries: oceans, large marine ecosystems, enclosed or semi-enclosed regional seas and estuaries, rivers, lakes, groundwater systems (aquifers), and wetlands [1]. Oceans and seas, waters... Icon sometimes used to indicate that source material came from a source not subject to copyright. ... For the Xzibit album, see Weapons of Mass Destruction (album). ... The mushroom cloud of the atomic bombing of Nagasaki, Japan, 1945, rose some 18 km (11 mi) above the epicenter. ...


A second treaty, the Moon Treaty, was proposed to restrict the exploitation of the Moon's resources by any single nation, but it has not been signed by any of the space-faring nations. Several individuals have made claims to the Moon in whole or in part, although none of these are generally considered credible.[75]  signed and ratified  only signed The Agreement Governing the Activities of States on the Moon and Other Celestial Bodies, better known as the Moon Treaty or Moon Agreement is an international treaty that turns jurisdiction of all heavenly bodies (including the orbits around such bodies) over to the international community. ... This is a list of government agencies engaged in activities related to outer space. ... This article or section does not cite its references or sources. ...


See also

Solar System Portal

Image File history File links Download high resolution version (1024x1274, 113 KB) Original caption released with image This is a montage of planetary images taken by spacecraft managed by the Jet Propulsion Laboratory in Pasadena, CA. Included are (from top to bottom) images of Mercury, Venus, Earth (and Moon), Mars... 3753 Cruithne (pronounced , Modern Irish ) is an asteroid in orbit around the Sun. ... The term blue moon has at least four related meanings. ... This article or section does not cite its references or sources. ... The Late Heavy Bombardment (LHB) was a period approximately 3. ... Map of the moon showing some landing sites. ... This is a list of the craters on the Moon. ... The Moons surface is covered in many interesting geologic features. ... This is a list of maria (singular mare) on the Moon. ... This is a list of mountains on the Moon: // These are isolated mountains or massifs. ... The Moons surface is covered in many interesting features. ... A lunar space elevator (also called a moonstalk) is a proposed cable running from the surface of the Moon into space. ... Look up Month in Wiktionary, the free dictionary. ... This article is about the Moon as the subject of and inspiration for creative works. ... Selenography is the study of the surface and physical features of the Moon, especially the mapping of the features according to the Moons latitude and longitude. ... Please wikify (format) this article as suggested in the Guide to layout and the Manual of Style. ...

References

Cited
  1. ^ a b c d e f g h i j k l Wieczorek, M.; et al. (2006). "The constitution and structure of the lunar interior". Reviews in Mineralogy and Geochemistry 60: 221–364. 
  2. ^ 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 the Earth's equatorial radius of 6378 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 fact sheet, and by calculating the brightness of the earthshine onto such a new moon. The brightness of the earthshine is Earth albedo × (Earth radius / Moon orbit radius) ² relative to the direct solar illumination that occurs for a full moon. Earth albedo = 0.367, Earth radius = (polar radius × equatorial radius)1/2=6367 km.
  3. ^ a b Williams, D.R. (February 10, 2006). Moon Fact Sheet. NASA. Retrieved on 2007-10-12.
  4. ^ 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". 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 the Earth's equatorial radius of 6378 km, giving 350 600 km.
  5. ^ A.R. Vasavada, D.A. Paige, and S.E. Wood. "Near-Surface Temperatures on Mercury and the Moon and the Stability of Polar Ice Deposits". Icarus 141: 179. 
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  7. ^ Lucey et al. (2006) give 107 particles cm−3 (day) and 105 particles cm−3 (night). Combining this with equatorial surface temperatures of 390 K (day)and 100 K (night), one can use the Ideal gas law to obtain pressures. Rounding to the nearest order of magnitude gives the infobox values of 10-7 Pa (day) and 10-10 Pa (night).
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General
  • Bussey, B.; Spudis, P.D. (2004). The Clementine Atlas of the Moon. Cambridge University Press. ISBN 0-521-81528-2. 
  • Jolliff, B.; Wieczorek, M.; Shearer, C.; Neal, C. (eds.) (2006). "New views of the Moon". Rev. Mineral. Geochem. 60: 721. Chantilly, Virginia: Min. Soc. Amer.. Retrieved on 2007-04-12. 
  • Moore, P. (2001). On the Moon. Tucson, Arizona: Sterling Publishing Co.. ISBN 0-304-35469-4. 
  • 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 Univ. Press, 307. 
  • Wilhelms, D.E. (1987). "Geologic History of the Moon". U.S. Geological Survey Professional paper 1348. Retrieved on 2007-04-12. 
  • Wilhelms, D.E. (1993). To a Rocky Moon: A Geologist's History of Lunar Exploration. Tucson, Arizona: University of Arizona Press. 

The lunar phase depends on the Moons position in orbit around Earth. ... Leonardo da Vincis sketch of crescent Moon with earthshine as part of his Codex Leicester, written between 1506 and 1510. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 285th day of the year (286th in leap years) in the Gregorian calendar. ... Isotherms of an ideal gas The ideal gas law is the equation of state of a hypothetical ideal gas, first stated by Benoît Paul Émile Clapeyron in 1834. ... The National Aeronautics and Space Administration (NASA) (IPA [ˈnæsÉ™]) is an agency of the United States government, responsible for the nations public space program. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 229th day of the year (230th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2000 (MM) was a leap year starting on Saturday (link will display full 2000 Gregorian calendar). ... is the 243rd day of the year (244th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2000 (MM) was a leap year starting on Saturday (link will display full 2000 Gregorian calendar). ... is the 276th day of the year (277th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 338th day of the year (339th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2003 (MMIII) was a common year starting on Wednesday of the Gregorian calendar. ... is the 155th day of the year (156th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 1998 (MCMXCVIII) was a common year starting on Thursday (link will display full 1998 Gregorian calendar). ... is the 198th day of the year (199th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2001 (MMI) was a common year starting on Monday (link displays the 2001 Gregorian calendar). ... is the 243rd day of the year (244th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 310th day of the year (311th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2001 (MMI) was a common year starting on Monday (link displays the 2001 Gregorian calendar). ... is the 243rd day of the year (244th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 241st day of the year (242nd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 312th day of the year (313th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... is the 111th day of the year (112th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... The National Aeronautics and Space Administration (NASA) (IPA [ˈnæsÉ™]) is an agency of the United States government, responsible for the nations public space program. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... is the 192nd day of the year (193rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 150th day of the year (151st in leap years) in the Gregorian calendar. ... Year 2001 (MMI) was a common year starting on Monday (link displays the 2001 Gregorian calendar). ... is the 135th day of the year (136th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... is the 192nd day of the year (193rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 150th day of the year (151st in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... May 2 is the 122nd day of the year in the Gregorian calendar (123rd in leap years). ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... For the band, see 1997 (band). ... is the 326th day of the year (327th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 240th day of the year (241st in leap years) in the Gregorian calendar. ... Also see: 2002 (number). ... is the 291st day of the year (292nd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... is the 207th day of the year (208th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Also: 1977 (album) by Ash. ... is the 244th day of the year (245th in leap years) in the Gregorian calendar. ... For information on Wikipedia press releases, see Wikipedia:Press releases. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 241st day of the year (242nd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 241st day of the year (242nd in leap years) in the Gregorian calendar. ... Year 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... is the 348th day of the year (349th in leap years) in the Gregorian calendar. ... For information on Wikipedia press releases, see Wikipedia:Press releases. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 338th day of the year (339th in leap years) in the Gregorian calendar. ... For information on Wikipedia press releases, see Wikipedia:Press releases. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... is the 193rd day of the year (194th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 264th day of the year (265th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 240th day of the year (241st in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 155th day of the year (156th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Clive Staples Lewis (November 29, 1898 – November 22, 1963), commonly referred to as C. S. Lewis, was an author and scholar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Paul D. Spudis is an American geologist and lunar scientist. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Sir Patrick Moore presenting The Sky at Night, October 2005 Sir Alfred Patrick Caldwell-Moore, CBE, HonFRS, FRAS (born 4 March 1923), known as Patrick Moore, is an English amateur astronomer who has attained legendary status in British astronomy as a writer and television presenter of the subject and who... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ...

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Wikipedia does not have an article with this exact name. ... Image File history File links Wikibooks-logo. ... Image File history File links Wikiquote-logo. ... Image File history File links Wikisource-logo. ... Image File history File links Commons-logo. ... Image File history File links WikiNews-Logo. ... Image File history File links Wikiversity-logo-Snorky. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2003 (MMIII) was a common year starting on Wednesday of the Gregorian calendar. ... is the 288th day of the year (289th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 272nd day of the year (273rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 313th day of the year (314th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 258th day of the year (259th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 239th day of the year (240th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 249th day of the year (250th in leap years) in the Gregorian calendar. ... For other uses, see Calendar (disambiguation) A page from the Hindu calendar 1871–1872. ... Look up Month in Wiktionary, the free dictionary. ... This article is about the Moon as the subject of and inspiration for creative works. ... The Moon has figured in many mythologies, often paired or contrasted with the Sun (see also Solar deity). ... The Moon illusion is an optical illusion in which the Moon appears larger near the horizon than it does while higher up in the sky. ... The lunar effect is the supposed influence of the moon, and its various phases, on human behaviour. ... The orbit of the Moon around the Earth is completed in approximately 27. ... Lunar phase refers to the appearance of the illuminated portion of the Moon as seen by an observer, usually on Earth. ... Photo taken during the 1999 eclipse. ... Time lapse movie of the 3 March 2007 lunar eclipse A lunar eclipse occurs whenever the Moon passes through some portion of the Earth’s shadow. ... This article is about tides in the Earths oceans. ... Schematic illustration of the internal structure of the Moon. ... Radial gravitational anomaly at the surface of the Moon. ... Topography of the Moon, referenced to the lunar geoid. ... Total magnetic field strength at the surface of the Moon as derived from the Lunar Prospector electron reflectometer experiment. ... The atmosphere of the Moon is very tenuous and insignificant in comparison to that of the Earth. ... Selenography is the study of the surface and physical features of the Moon, especially the mapping of the features according to the Moons latitude and longitude. ... The near side of the Moon is the lunar hemisphere that is permanently turned towards the Earth, and as such the side which is always seen. ... Far side of the Moon. ... Lunar nearside with major maria and craters labeled A global albedo map of the Moon obtained from the Clementine missionThe dark regions are the lunar maria, whereas the lighter regions are the highlands. ... Tycho crater on Earths moon. ... The South Pole-Aitken basin is an impact crater on Earths Moon. ... Shackleton is a lunar crater that lies at the south pole of the Moon. ... The continuous bombardment of the Moon by comets and meteoroids have added some amount of water to the lunar surface. ... Peak of Eternal Light (PEL) describes a point on a body within the solar system which is eternally bathed in sunlight. ... Please wikify (format) this article as suggested in the Guide to layout and the Manual of Style. ... This map, based on a survey of 300 TLPs by Barbara Middlehurst and Patrick Moore, shows the approximate distribution of observed events. ... Exploring Shorty crater during the Apollo 17 mission to the Moon. ... The lunar geologic timescale (or perhaps more properly the selenologic timescale) divides the history of Earths Moon into six generally recognized geologic periods: Copernician Period : 1100 MY to present Eratosthenian Period : 3200 MY to 1100 MY Upper Imbrian Epoch : 3800 MY to 3200 MY Lower Imbrian Epoch : 3850 MY... The Big Splash redirects here. ... Lunar Ferroan Anorthosite #60025 (Plagioclase Feldspar). ... Lunar Meteorite Allan Hills 81005 A Lunar meteorite is a meteorite that is known to have originated on the Moon. ... KREEP stands for potassium (atomic symbol K), rare earth elements (REE), and phosphorus (P). ... The Apollo Lunar Surface Experiment Package, or ALSEP, was a set of connected scientific instruments left on the Moon when the Apollo program ended. ... The Lunar Laser Ranging Experiment from the Apollo 11 mission The ongoing Lunar Laser Ranging Experiment measures the distance between the Earth and the Moon using laser ranging. ... The Late Heavy Bombardment (LHB) was a period approximately 3. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Project Apollo was a series of human spaceflight missions undertaken by the United States of America (NASA) using the Apollo spacecraft and Saturn launch vehicle, conducted during the years 1961 – 1975. ... Pioneer 0 (USA, 1958) - failure - orbiter Pioneer 1 (USA, 1958) - failure - orbiter Pioneer 3 (USA, 1958) - failure - flyby Luna 1 (Soviet Union, 1959) - success - flyby Pioneer 4 (USA, 1959) - partial success - flyby Luna 2 (Soviet Union, 1959) - success - impactor Luna 3 (Soviet Union, 1959) - success - flyby Ranger 3 (USA, 1962... It has been suggested that this article or section be merged into Exploration of the Moon. ... Lunar outpost redirects here. ... Buzz Aldrin and Neil Armstrong in NASAs training mockup of the Moon and lander module. ... This article is about the Solar System. ... A natural satellite is an object that orbits a planet or other body larger than itself and which is not man-made. ... A natural satellite is an object that orbits a planet or other body larger than itself and which is not man-made. ... This article is about the Solar System. ... The relative sizes of and distance between Mars, Phobos, and Deimos, to scale. ... Jupiters outer moons and their highly inclined orbits. ... The Saturnian system (photographic montage) Saturn has 60 confirmed natural satellites, plus three hypothetical moons. ... Uranus has 27 known moons. ... Neptune (top) and Triton (bottom), 3 days after the Voyager 2 flyby. ... Image File history File links Download high resolution version (604x602, 23 KB)Cassini color image of Rhea taken Jan. ... The planet Pluto has three known moons. ... Dysnomia (officially designated (136199) Eris I Dysnomia) is a moon of the dwarf planet Eris. ... 243 Ida and its moon Dactyl An asteroid moon is an asteroid that orbits another asteroid. ... This article is about the natural satellite of Jupiter. ... Titan (, from Ancient Greek Τῑτάν) or Saturn VI is the largest moon of Saturn and the only moon known to have a dense atmosphere. ... There is also an asteroid named 204 Kallisto. ... Atmosphere Surface pressure: trace Composition: 90% sulfur dioxide Io (eye-oe, IPA: , Greek Ῑώ) is the innermost of the four Galilean moons of Jupiter and, with a diameter of 3,642 kilometers, is the fourth largest moon in the Solar System. ... Apparent magnitude: 5. ... Triton (trye-tÉ™n, IPA: , Greek Τρίτων), or Neptune I, is the planet Neptunes largest moon. ... Atmospheric pressure   Titania (ti-taan-ee-É™ or tye-tan-ee-É™) is the largest moon of Uranus. ... Atmosphere none Rhea (ree-a, Greek ‘Ρέα) is the second largest moon of Saturn and was discovered in 1672 by Giovanni Domenico Cassini. ... Atmospheric pressure 0 kPa Oberon (oe-bur-on) is the outermost of the major moons of the planet Uranus. ... Iapetus (eye-ap-É™-tÉ™s, IPA , Greek Ιαπετός) is the third-largest moon of Saturn, discovered by Giovanni Domenico Cassini in 1671. ... Charon (shair-É™n or kair-É™n (key), IPA , Greek Χάρων), discovered in 1978, is, depending on the definition employed, either the largest moon of Pluto or one member of a double dwarf planet with Pluto being the other member. ... Atmospheric pressure 0 kPa Umbriel (um-bree-É™l, IPA ) is a moon of Uranus discovered on 1851-10-24 by William Lassell. ... Atmospheric pressure 0 kPa Ariel (air-ee-É™l, IPA ) is a moon of Uranus discovered on 24 October 1851 by William Lassell. ... Atmosphere none Dione (dye-oe-nee, Greek Διώνη) is a moon of Saturn discovered by Giovanni Cassini in 1684. ... Atmosphere none Tethys (tee-thÉ™s or teth-É™s, IPA , Greek Τηθύς) is a moon of Saturn that was discovered by Giovanni Domenico Cassini in 1684. ... Atmosphere Surface pressure: trace, significant spatial variability[8][9] Composition: 91% Water vapour 4% Nitrogen 3. ... Miranda (IPA: ) is the smallest and innermost of Uranus five major moons. ... Atmospheric pressure 0 kPa Proteus (proe-tee-us, Greek Πρωτέας) is one of Neptunes moons. ... Mimas (mee-mÉ™s or mye-mÉ™s, IPA: , Greek Μίμᾱς, rarely Μίμανς) is a moon of Saturn that was discovered in 1789 by William Herschel. ... In astronomy, an inner satellite is a natural satellite following a prograde, low inclination orbit inwards of the large satellites of the parent planet. ... A Trojan moon is a natural satellite of a planet occupying the L4 or L5 equilateral Lagrangian points of a primary-moon system. ... In astronomy, an irregular satellite is a natural satellite following a distant, inclined, often retrograde orbit and believed to be captured as opposed to a regular satellite, formed in situ. ... This is a list of natural satellites in the solar system: Mercury: none Venus: none Earth: Moon Mars: Phobos Deimos Jupiter: see Jupiters natural satellites Saturn: see Saturns natural satellites Uranus: see Uranus natural satellites Neptune: see Neptunes natural satellites Pluto: Charon In addition, various asteroids are... This is a list of natural satellites in the solar system, ordered from largest to smallest by average diameter. ... This timeline of discovery of Solar System planets and their natural satellites charts the progress of the discovery of new bodies over history. ... The naming of natural satellites has been the responsibility of the IAUs committee for Planetary System Nomenclature since 1973. ... This article is about the Solar System. ... Sol redirects here. ... [[Link titleBold text // ]] This article is about the planet. ... For other uses, see Venus (disambiguation). ... This article is about Earth as a planet. ... Adjectives: Martian Atmosphere Surface pressure: 0. ... Spectral type: G[8] Absolute magnitude: 3. ... For other uses, see Jupiter (disambiguation). ... This article is about the planet. ... For other uses, see Uranus (disambiguation). ... For other uses, see Neptune (disambiguation). ... For other uses, see Pluto (disambiguation). ... Absolute magnitude: −1. ... This article is about the astronomical term. ... Artists impression of Pluto (background) and Charon (foreground). ... A natural satellite is an object that orbits a planet or other body larger than itself and which is not man-made. ... The relative sizes of and distance between Mars, Phobos, and Deimos, to scale : Phobos (top) and Deimos (bottom). ... Jupiters 4 Galilean moons, in a composite image comparing their sizes and the size of Jupiter (Great Red Spot visible). ... The Saturnian system (photographic montage) Moons of Saturn (photographic montage) Saturn has 60 confirmed natural satellites, plus three hypothetical moons. ... Uranus has twenty-seven known moons. ... Neptune (top) and Triton (bottom), 3 days after the Voyager 2 flyby. ... Hubble image of the Plutonian system Pluto has three known moons. ... Dysnomia (officially designated (136199) Eris I Dysnomia) is a moon of the dwarf planet Eris. ... A Small Solar System Body (SSSB) is a term defined in 2006 by the International Astronomical Union to describe objects in the Solar System that are neither planets nor dwarf planets: [1] This encompasses: all minor planets apart from the dwarf planets, : the classical asteroids, (except for 1 Ceres, the... “Meteor” redirects here. ... For other uses, see Asteroid (disambiguation). ... 243 Ida and its moon Dactyl An asteroid moon is an asteroid that orbits another asteroid. ... For other uses, see Asteroid (disambiguation). ... The centaurs are a class of icy planetoids that orbit the Sun between Jupiter and Neptune, named after the mythical race of centaurs. ... A trans-Neptunian object (TNO) is any object in the solar system that orbits the sun at a greater distance on average than Neptune. ... The Kuiper belt, derived from data from the Minor Planet Center. ... Eris, the largest known scattered disc object (center), and its moon Dysnomia (left of center). ... Comet Hale-Bopp Comet West For other uses, see Comet (disambiguation). ... This image is an artists rendering of the Oort cloud and the Kuiper Belt. ... Astronomical objects are significant physical entities, associations or structures which current science has confirmed to exist in space. ... Below is a list of solar system objects with diameter >500km: The Sun, a spectral class G2 star Mercury Venus Earth Moon Mars Jupiter Io Europa Ganymede Callisto complete list of Jupiters natural satellites Saturn Tethys Dione Rhea Titan Iapetus complete list of Saturns natural satellites Uranus Ariel... It has been suggested that Planetary-size comparison be merged into this article or section. ... This is a list of solar system objects by mass, in decreasing order. ...


  Results from FactBites:
 
Moon Phases :: Calendars (941 words)
The phases of the moon are caused by the relative positions of the earth, sun, and moon.
When the moon is between the earth and the sun, it appears dark, a "new" moon.
Because the "horns" of the moon at the ends of the crescent are always facing away from the setting or rising sun, they always point upward in the sky.
Moon - MSN Encarta (1024 words)
The Moon is the second brightest object in Earth’s sky, after the Sun, and has accordingly been an object of wonder and speculation for people since earliest times.
The average density of the Moon is only three-fifths that of Earth, and gravity at the lunar surface is only one-sixth as strong as gravity at sea level on Earth.
The Moon rotates once on its axis in the same period of time that it circles Earth, accounting for the fact that virtually the same portion of the Moon (the “near side”) is always turned toward Earth.
  More results at FactBites »

 
 

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