Jump to content

Moon

Page semi-protected
From Wikipedia, the free encyclopedia

Moon
Full Moon in the darkness of the night sky. It is patterned with a mix of light-tone regions and darker, irregular blotches, and scattered with varied circles surrounded by out-thrown rays of bright ejecta: impact craters.
Designations
Designation
Earth I
Adjectives
Symbol☾ or ☽
Orbital characteristics
Epoch J2000
Perigee362600 km
(356400370400 km)
Apogee405400 km
(404000406700 km)
384399 km  (1.28 ls, 0.00257 AU)[1]
Eccentricity0.0549[1]
27.321661 d
(27 d 7 h 43 min 11.5 s[1])
29.530589 d
(29 d 12 h 44 min 2.9 s)
1.022 km/s
Inclination5.145° to the ecliptic[2][a]
Regressing by one revolution in 18.61 years
Progressing by one
revolution in 8.85 years
Satellite ofEarth[b][3]
Physical characteristics
1737.4 km  
(0.2727 of Earth's)[1][4][5]
Equatorial radius
1738.1 km  
(0.2725 of Earth's)[4]
Polar radius
1736.0 km  
(0.2731 of Earth's)[4]
Flattening0.0012[4]
Circumference10921 km  (equatorial)
3.793×107 km2  
(0.074 of Earth's)
Volume2.1958×1010 km3  
(0.02 of Earth's)[4]
Mass7.346×1022 kg  
(0.0123 of Earth's)[1][4][6]
Mean density
3.344 g/cm3[1][4]
0.606 × Earth
1.622 m/s2 (5.32 ft/s2)[4]
0.1654 g0
0.3929±0.0009[7]
2.38 km/s
(8600 km/h; 5300 mph)
29.530589 d
(29 d 12 h 44 min 2.9 s; synodic; solar day) (spin-orbit locked)
27.321661 d  (spin-orbit locked)
Equatorial rotation velocity
4.627 m/s
North pole right ascension
  • 17h 47m 26s
  • 266.86°[10]
North pole declination
65.64°[10]
Albedo0.136[11]
Surface temp. min mean max
Equator 100 K[12] 250 K 390 K[12]
85°N  150 K 230 K[13]
Surface absorbed dose rate13.2 μGy/h
(during lunar daytime)[14]
Surface equivalent dose rate57.0 μSv/h
(during lunar daytime)[14]
0.2[15]
29.3 to 34.1 arcminutes[4][d]
Atmosphere[16]
Surface pressure
  • 10−7 Pa (1 picobar)  (day)
  • 10−10 Pa (1 femtobar)   
    (night)[e]
Composition by volume

The Moon is Earth's only natural satellite. It orbits at an average distance of 384,400 km (238,900 mi), about 30 times the diameter of Earth. Tidal forces between Earth and the Moon have synchronized the Moon's orbital period (lunar month) with its rotation period (lunar day) at 29.5 Earth days, causing the same side of the Moon to always face Earth. The Moon's gravitational pull—and, to a lesser extent, the Sun's—are the main drivers of Earth's tides.

In geophysical terms, the Moon is a planetary-mass object or satellite planet. Its mass is 1.2% that of the Earth, and its diameter is 3,474 km (2,159 mi), roughly one-quarter of Earth's (about as wide as the United States from coast to coast). Within the Solar System, it is the largest and most massive satellite in relation to its parent planet, the fifth largest and most massive moon overall, and larger and more massive than all known dwarf planets.[17] Its surface gravity is about one sixth of Earth's, about half of that of Mars, and the second highest among all Solar System moons, after Jupiter's moon Io. The body of the Moon is differentiated and terrestrial, with no significant hydrosphere, atmosphere, or magnetic field. It formed 4.51 billion years ago, not long after Earth's formation, out of the debris from a giant impact between Earth and a hypothesized Mars-sized body called Theia.

The lunar surface is covered in lunar dust and marked by mountains, impact craters, their ejecta, ray-like streaks, rilles and, mostly on the near side of the Moon, by dark maria ("seas"), which are plains of cooled magma. These maria were formed when molten lava flowed into ancient impact basins. The Moon is, except when passing through Earth's shadow during a lunar eclipse, always illuminated by the Sun, but from Earth the visible illumination shifts during its orbit, producing the lunar phases.[18] The Moon is the brightest celestial object in Earth's night sky. This is mainly due to its large angular diameter, while the reflectance of the lunar surface is comparable to that of asphalt. The apparent size is nearly the same as that of the Sun, allowing it to cover the Sun completely during a total solar eclipse. From Earth about 59% of the lunar surface is visible over time due to cyclical shifts in perspective (libration), making parts of the far side of the Moon visible.

The Moon has been an important source of inspiration and knowledge for humans, having been crucial to cosmography, mythology, religion, art, time keeping, natural science, and spaceflight. In 1959, the first human-made objects to leave Earth and reach another body arrived at the Moon, with the flyby of the Soviet Union's Luna 1 and the intentional impact of Luna 2. In 1966, the Moon became the first extraterrestrial body with a soft landing by Luna 9 and a orbital insertion by Luna 10 were achieved. On July 20, 1969, humans for the first time landed on the Moon and any extraterrestrial body, at Mare Tranquillitatis with the lander Eagle of the United States' Apollo 11 mission. Five more crews were sent between then and 1972, each with two men landing on the surface. The longest stay was 75 hours by the Apollo 17 crew. Since then, exploration of the Moon has continued robotically, and crewed missions are being planned to return beginning in the late 2020s.

Names and etymology

The usual English proper name for Earth's natural satellite is simply Moon, with a capital M.[19][20] The noun moon is derived from Old English mōna, which (like all its Germanic cognates) stems from Proto-Germanic *mēnōn,[21] which in turn comes from Proto-Indo-European *mēnsis 'month'[22] (from earlier *mēnōt, genitive *mēneses) which may be related to the verb 'measure' (of time).[23]

Occasionally, the name Luna /ˈlnə/ is used in scientific writing[24] and especially in science fiction to distinguish the Earth's moon from others, while in poetry "Luna" has been used to denote personification of the Moon.[25] Cynthia /ˈsɪnθiə/ is another poetic name, though rare, for the Moon personified as a goddess,[26] while Selene /səˈln/ (literally 'Moon') is the Greek goddess of the Moon.

The English adjective pertaining to the Moon is lunar, derived from the Latin word for the Moon, lūna. Selenian /səlniən/[27] is an adjective used to describe the Moon as a world, rather than as a celestial object,[28] but its use is rare. It is derived from σελήνη selēnē, the Greek word for the Moon, and its cognate selenic was originally a rare synonym[29] but now nearly always refers to the chemical element selenium.[30] The element name selenium and the prefix seleno- (as in selenography, the study of the physical features of the Moon) come from this Greek word.[31][32]

The Greek goddess of the wilderness and the hunt, Artemis, equated with the Roman Diana, one of whose symbols was the Moon and who was often regarded as the goddess of the Moon, was also called Cynthia, from her legendary birthplace on Mount Cynthus.[33] These names – Luna, Cynthia and Selene – are reflected in technical terms for lunar orbits such as apolune, pericynthion and selenocentric.

The astronomical symbol for the Moon is a crescent\decrescent, ☽\☾, for example in M 'lunar mass' (also ML).

Natural history

Lunar geologic timescale

Early ImbrianLate ImbrianPre-NectarianNectarianEratosthenianCopernican period
Millions of years before present


The lunar geological periods are named after their characteristic features, from most impact craters outside the dark mare, to the mare and later craters, and finally the young, still bright and therefore readily visible craters with ray systems like Copernicus or Tycho.

Formation

The far side of the Moon, lacking the near side's characteristic large dark areas of maria, resembling how the near side of the Moon might have looked early in the Moon's history[34][35]

Isotope dating of lunar samples suggests the Moon formed around 50 million years after the origin of the Solar System.[36][37] Historically, several formation mechanisms have been proposed,[38] but none satisfactorily explains the features of the Earth–Moon system. A fission of the Moon from Earth's crust through centrifugal force[39] would require too great an initial rotation rate of Earth.[40] Gravitational capture of a pre-formed Moon[41] depends on an unfeasibly extended atmosphere of Earth to dissipate the energy of the passing Moon.[40] A co-formation of Earth and the Moon together in the primordial accretion disk does not explain the depletion of metals in the Moon.[40] None of these hypotheses can account for the high angular momentum of the Earth–Moon system.[42]

The prevailing theory is that the Earth–Moon system formed after a giant impact of a Mars-sized body (named Theia) with the proto-Earth. The oblique impact blasted material into orbit about the Earth and the material accreted and formed the Moon[43][44] just beyond the Earth's Roche limit of ~2.56 R🜨.[45]

Giant impacts are thought to have been common in the early Solar System. Computer simulations of giant impacts have produced results that are consistent with the mass of the lunar core and the angular momentum of the Earth–Moon system. These simulations show that most of the Moon derived from the impactor, rather than the proto-Earth.[46] However, models from 2007 and later suggest a larger fraction of the Moon derived from the proto-Earth.[47][48][49][50] Other bodies of the inner Solar System such as Mars and Vesta have, according to meteorites from them, very different oxygen and tungsten isotopic compositions compared to Earth. However, Earth and the Moon have nearly identical isotopic compositions. The isotopic equalization of the Earth-Moon system might be explained by the post-impact mixing of the vaporized material that formed the two,[51] although this is debated.[52]

The impact would have released enough energy to liquefy both the ejecta and the Earth's crust, forming a magma ocean. The liquefied ejecta could have then re-accreted into the Earth–Moon system.[53][54] The newly formed Moon would have had its own magma ocean; its depth is estimated from about 500 km (300 miles) to 1,737 km (1,079 miles).[53]

While the giant-impact theory explains many lines of evidence, some questions are still unresolved, most of which involve the Moon's composition.[55] Models that have the Moon acquiring a significant amount of the proto-earth are more difficult to reconcile with geochemical data for the isotopes of zirconium, oxygen, silicon, and other elements.[56] A study published in 2022, using high-resolution simulations (up to 108 particles), found that giant impacts can immediately place a satellite with similar mass and iron content to the Moon into orbit far outside Earth's Roche limit. Even satellites that initially pass within the Roche limit can reliably and predictably survive, by being partially stripped and then torqued onto wider, stable orbits.[57]

On November 1, 2023, scientists reported that, according to computer simulations, remnants of a protoplanet, named Theia, could be inside the Earth, left over from a collision with the Earth in ancient times, which also formed the Moon.[58][59]

Natural development

Artist's depiction of the Moon as it might have appeared in Earth's sky after the Late Heavy Bombardment around 4 billion years ago. At that time the Moon orbited the Earth at half its current distance, making it appear 2.8 times larger than it does today.[60]

The newly formed Moon settled into a much closer Earth orbit than it has today. Each body therefore appeared much larger in the sky of the other, eclipses were more frequent, and tidal effects were stronger.[60] Due to tidal acceleration, the Moon's orbit around Earth has become significantly larger, with a longer period.[61]

Following formation, the Moon has cooled and most of its atmosphere has been stripped.[62] The lunar surface has since been shaped by large impact events and many small ones, forming a landscape featuring craters of all ages.

The Moon was volcanically active until 1.2 billion years ago, which laid down the prominent lunar maria. Most of the mare basalts erupted during the Imbrian period, 3.3–3.7 billion years ago, though some are as young as 1.2 billion years[63] and some as old as 4.2 billion years.[64] There are differing explanations for the eruption of mare basalts, particularly their uneven occurrence which mainly appear on the near-side. Causes of the distribution of the lunar highlands on the far side are also not well understood. Topological measurements show the near side crust is thinner than the far side. One possible scenario then is that large impacts on the near side may have made it easier for lava to flow onto the surface.[65]

Physical characteristics

The Moon is a very slightly scalene ellipsoid due to tidal stretching, with its long axis displaced 30° from facing the Earth, due to gravitational anomalies from impact basins. Its shape is more elongated than current tidal forces can account for. This 'fossil bulge' indicates that the Moon solidified when it orbited at half its current distance to the Earth, and that it is now too cold for its shape to restore hydrostatic equilibrium at its current orbital distance.[66]

Size and mass

Size comparison of the main moons of the Solar System with Earth to scale. Nineteen moons are large enough to be round, several having subsurface oceans and one, Titan, having a considerable atmosphere.

The Moon is by size and mass the fifth largest natural satellite of the Solar System, categorizable as one of its planetary-mass moons, making it a satellite planet under the geophysical definitions of the term.[17] It is smaller than Mercury and considerably larger than the largest dwarf planet of the Solar System, Pluto. While the minor-planet moon Charon of the Pluto-Charon system is larger relative to Pluto,[f][67] the Moon is the largest natural satellite of the Solar System relative to their primary planets.[g]

The Moon's diameter is about 3,500 km, more than a quarter of Earth's, with the face of the Moon comparable to the width of either Mainland Australia,[68] Europe or the Contiguous United States (which excludes Alaska, etc.).[69] The whole surface area of the Moon is about 38 million square kilometers, comparable to North and South America combined,[70] the combined American landmass having an area (excluding all islands) of 37.7 million square kilometers.[71]

The Moon's mass is 1/81 of Earth's,[72] being the second densest among the planetary moons, and having the second highest surface gravity, after Io, at 0.1654 g and an escape velocity of 2.38 km/s (8600 km/h; 5300 mph).

Structure

Moon's internal structure: solid inner core (iron-metallic), molten outer core, hardened mantle and crust. The crust on the Moon's near side permanently facing Earth is thinner, featuring larger areas flooded by material of the once molten mantle forming today's lunar mare.

The Moon is a differentiated body that was initially in hydrostatic equilibrium but has since departed from this condition.[73] It has a geochemically distinct crust, mantle, and core. The Moon has a solid iron-rich inner core with a radius possibly as small as 240 kilometres (150 mi) and a fluid outer core primarily made of liquid iron with a radius of roughly 300 kilometres (190 mi). Around the core is a partially molten boundary layer with a radius of about 500 kilometres (310 mi).[74][75] This structure is thought to have developed through the fractional crystallization of a global magma ocean shortly after the Moon's formation 4.5 billion years ago.[76]

Crystallization of this magma ocean would have created a mafic mantle from the precipitation and sinking of the minerals olivine, clinopyroxene, and orthopyroxene; after about three-quarters of the magma ocean had crystallized, lower-density plagioclase minerals could form and float into a crust atop.[77] The final liquids to crystallize would have been initially sandwiched between the crust and mantle, with a high abundance of incompatible and heat-producing elements.[1] Consistent with this perspective, geochemical mapping made from orbit suggests a crust of mostly anorthosite.[16] The Moon rock samples of the flood lavas that erupted onto the surface from partial melting in the mantle confirm the mafic mantle composition, which is more iron-rich than that of Earth.[1] The crust is on average about 50 kilometres (31 mi) thick.[1]

The Moon is the second-densest satellite in the Solar System, after Io.[78] However, the inner core of the Moon is small, with a radius of about 350 kilometres (220 mi) or less,[1] around 20% of the radius of the Moon. Its composition is not well understood, but is probably metallic iron alloyed with a small amount of sulfur and nickel; analyzes of the Moon's time-variable rotation suggest that it is at least partly molten.[79] The pressure at the lunar core is estimated to be 5 GPa (49,000 atm).[80]

Gravitational field

Astronaut John Young jumping on the Moon, illustrating that the gravitational pull of the Moon is approximately 1/6 of Earth's. The jumping height is limited by the EVA space suit's weight on the Moon of about 13.6 kg (30 lb) and by the suit's pressurization resisting the bending of the suit, as needed for jumping.[81][82]

On average the Moon's surface gravity is 1.62 m/s2[4] (0.1654 g; 5.318 ft/s2), about half of the surface gravity of Mars and about a sixth of Earth's.

The Moon's gravitational field is not uniform. The details of the gravitational field have been measured through tracking the Doppler shift of radio signals emitted by orbiting spacecraft. The main lunar gravity features are mascons, large positive gravitational anomalies associated with some of the giant impact basins, partly caused by the dense mare basaltic lava flows that fill those basins.[83][84] The anomalies greatly influence the orbit of spacecraft about the Moon. There are some puzzles: lava flows by themselves cannot explain all of the gravitational signature, and some mascons exist that are not linked to mare volcanism.[85]

Magnetic field

The Moon has an external magnetic field of less than 0.2 nanoteslas,[86] or less than one hundred thousandth that of Earth. The Moon does not have a global dipolar magnetic field and only has crustal magnetization likely acquired early in its history when a dynamo was still operating.[87][88] Early in its history, 4 billion years ago, its magnetic field strength was likely close to that of Earth today.[86] This early dynamo field apparently expired by about one billion years ago, after the lunar core had crystallized.[86] Theoretically, some of the remnant magnetization may originate from transient magnetic fields generated during large impacts through the expansion of plasma clouds. These clouds are generated during large impacts in an ambient magnetic field. This is supported by the location of the largest crustal magnetizations situated near the antipodes of the giant impact basins.[89]

Atmosphere

The thin lunar atmosphere is visible on the Moon's surface at sunrise and sunset with the lunar horizon glow[90] and lunar twilight rays, like Earth's crepuscular rays. This Apollo 17 sketch depicts the glow and rays[91] among the general zodiacal light.[92][93]

The Moon has an atmosphere so tenuous as to be nearly vacuum, with a total mass of less than 10 tonnes (9.8 long tons; 11 short tons).[94] The surface pressure of this small mass is around 3 × 10−15 atm (0.3 nPa); it varies with the lunar day. Its sources include outgassing and sputtering, a product of the bombardment of lunar soil by solar wind ions.[16][95] Elements that have been detected include sodium and potassium, produced by sputtering (also found in the atmospheres of Mercury and Io); helium-4 and neon[96] from the solar wind; and argon-40, radon-222, and polonium-210, outgassed after their creation by radioactive decay within the crust and mantle.[97][98] The absence of such neutral species (atoms or molecules) as oxygen, nitrogen, carbon, hydrogen and magnesium, which are present in the regolith, is not understood.[97] Water vapor has been detected by Chandrayaan-1 and found to vary with latitude, with a maximum at ~60–70 degrees; it is possibly generated from the sublimation of water ice in the regolith.[99] These gases either return into the regolith because of the Moon's gravity or are lost to space, either through solar radiation pressure or, if they are ionized, by being swept away by the solar wind's magnetic field.[97]

Studies of Moon magma samples retrieved by the Apollo missions demonstrate that the Moon had once possessed a relatively thick atmosphere for a period of 70 million years between 3 and 4 billion years ago. This atmosphere, sourced from gases ejected from lunar volcanic eruptions, was twice the thickness of that of present-day Mars. The ancient lunar atmosphere was eventually stripped away by solar winds and dissipated into space.[62]

A permanent Moon dust cloud exists around the Moon, generated by small particles from comets. Estimates are 5 tons of comet particles strike the Moon's surface every 24 hours, resulting in the ejection of dust particles. The dust stays above the Moon approximately 10 minutes, taking 5 minutes to rise, and 5 minutes to fall. On average, 120 kilograms of dust are present above the Moon, rising up to 100 kilometers above the surface. Dust counts made by LADEE's Lunar Dust EXperiment (LDEX) found particle counts peaked during the Geminid, Quadrantid, Northern Taurid, and Omicron Centaurid meteor showers, when the Earth, and Moon pass through comet debris. The lunar dust cloud is asymmetric, being more dense near the boundary between the Moon's dayside and nightside.[100][101]

Surface conditions

Gene Cernan with lunar dust stuck on his suit. Lunar dust is highly abrasive and can cause damage to human lungs, nervous, and cardiovascular systems.[102]

Ionizing radiation from cosmic rays, the Sun and the resulting neutron radiation[103] produce radiation levels on average of 1.369 millisieverts per day during lunar daytime,[14] which is about 2.6 times more than on the International Space Station with 0.53 millisieverts per day at about 400 km above Earth in orbit, 5–10 times more than during a trans-Atlantic flight, 200 times more than on Earth's surface.[104] For further comparison radiation on a flight to Mars is about 1.84 millisieverts per day and on Mars on average 0.64 millisieverts per day, with some locations on Mars possibly having levels as low as 0.342 millisieverts per day.[105][106]

The Moon's axial tilt with respect to the ecliptic is only 1.5427°,[8][107] much less than the 23.44° of Earth. Because of this small tilt, the Moon's solar illumination varies much less with season than on Earth and it allows for the existence of some peaks of eternal light at the Moon's north pole, at the rim of the crater Peary.

The surface is exposed to drastic temperature differences ranging from 120 °C to −171 °C depending on the solar irradiance. Because of the lack of atmosphere, temperatures of different areas vary particularly upon whether they are in sunlight or shadow,[108] making topographical details play a decisive role on local surface temperatures.[109] Parts of many craters, particularly the bottoms of many polar craters,[110] are permanently shadowed, these "craters of eternal darkness" have extremely low temperatures. The Lunar Reconnaissance Orbiter measured the lowest summer temperatures in craters at the southern pole at 35 K (−238 °C; −397 °F)[111] and just 26 K (−247 °C; −413 °F) close to the winter solstice in the north polar crater Hermite. This is the coldest temperature in the Solar System ever measured by a spacecraft, colder even than the surface of Pluto.[109]

Blanketed on top of the Moon's crust is a highly comminuted (broken into ever smaller particles) and impact gardened mostly gray surface layer called regolith, formed by impact processes. The finer regolith, the lunar soil of silicon dioxide glass, has a texture resembling snow and a scent resembling spent gunpowder.[112] The regolith of older surfaces is generally thicker than for younger surfaces: it varies in thickness from 10–15 m (33–49 ft) in the highlands and 4–5 m (13–16 ft) in the maria.[113] Beneath the finely comminuted regolith layer is the megaregolith, a layer of highly fractured bedrock many kilometers thick.[114]

These extreme conditions for example are considered to make it unlikely for spacecraft to harbor bacterial spores at the Moon longer than just one lunar orbit.[115]

Surface features

Apollo 17 astronaut Harrison H. Schmitt next to the large Moon boulder nicknamed "Tracy's Rock"

The topography of the Moon has been measured with laser altimetry and stereo image analysis.[116] Its most extensive topographic feature is the giant far-side South Pole–Aitken basin, some 2,240 km (1,390 mi) in diameter, the largest crater on the Moon and the second-largest confirmed impact crater in the Solar System.[117][118] At 13 km (8.1 mi) deep, its floor is the lowest point on the surface of the Moon.[117][119] The highest elevations of the Moon's surface are located directly to the northeast, which might have been thickened by the oblique formation impact of the South Pole–Aitken basin.[120] Other large impact basins such as Imbrium, Serenitatis, Crisium, Smythii, and Orientale possess regionally low elevations and elevated rims.[117] The far side of the lunar surface is on average about 1.9 km (1.2 mi) higher than that of the near side.[1]

The discovery of fault scarp cliffs suggest that the Moon has shrunk by about 90 metres (300 ft) within the past billion years.[121] Similar shrinkage features exist on Mercury. Mare Frigoris, a basin near the north pole long assumed to be geologically dead, has cracked and shifted. Since the Moon does not have tectonic plates, its tectonic activity is slow and cracks develop as it loses heat.[122]

Scientists have confirmed the presence of a cave on the Moon near the Sea of Tranquillity, not far from the 1969 Apollo 11 landing site. The cave, identified as an entry point to a collapsed lava tube, is roughly 45 meters wide and up to 80 m long. This discovery marks the first confirmed entry point to a lunar cave. The analysis was based on photos taken in 2010 by NASA's Lunar Reconnaissance Orbiter. The cave's stable temperature of around 17 °C could provide a hospitable environment for future astronauts, protecting them from extreme temperatures, solar radiation, and micrometeorites. However, challenges include accessibility and risks of avalanches and cave-ins. This discovery offers potential for future lunar bases or emergency shelters.[123]

Volcanic features

The names of the main volcanic features the maria (blue) and some crater (brown) features of the near side of the Moon

The main features visible from Earth by the naked eye are dark and relatively featureless lunar plains called maria (singular mare; Latin for "seas", as they were once believed to be filled with water)[124] are vast solidified pools of ancient basaltic lava. Although similar to terrestrial basalts, lunar basalts have more iron and no minerals altered by water.[125] The majority of these lava deposits erupted or flowed into the depressions associated with impact basins, though the Moon's largest expanse of basalt flooding, Oceanus Procellarum, does not correspond to an obvious impact basin. Different episodes of lava flows in maria can often be recognized by variations in surface albedo and distinct flow margins.[126]

As the maria formed, cooling and contraction of the basaltic lava created wrinkle ridges in some areas. These low, sinuous ridges can extend for hundreds of kilometers and often outline buried structures within the mare. Another result of maria formation is the creation of concentric depressions along the edges, known as arcuate rilles. These features occur as the mare basalts sink inward under their own weight, causing the edges to fracture and separate.

In addition to the visible maria, the Moon has mare deposits covered by ejecta from impacts. Called cryptomares, these hidden mares are likely older than the exposed ones.[127] Conversely, mare lava has obscured many impact melt sheets and pools. Impact melts are formed when intense shock pressures from collisions vaporize and melt zones around the impact site. Where still exposed, impact melt can be distinguished from mare lava by its distribution, albedo, and texture.[128]

Sinuous rilles, found in and around maria, are likely extinct lava channels or collapsed lava tubes. They typically originate from volcanic vents, meandering and sometimes branching as they progress. The largest examples, such as Schroter's Valley and Rima Hadley, are significantly longer, wider, and deeper than terrestrial lava channels, sometimes featuring bends and sharp turns that again, are uncommon on Earth.

Mare volcanism has altered impact craters in various ways, including filling them to varying degrees, and raising and fracturing their floors from uplift of mare material beneath their interiors. Examples of such craters include Taruntius and Gassendi. Some craters, such as Hyginus, are of wholly volcanic origin, forming as calderas or collapse pits. Such craters are relatively rare, and tend to be smaller (typically a few kilometers wide), shallower, and more irregularly shaped than impact craters. They also lack the upturned rims characteristic of impact craters.

Several geologic provinces containing shield volcanoes and volcanic domes are found within the near side maria.[129] There are also some regions of pyroclastic deposits, scoria cones and non-basaltic domes made of particularly high viscosity lava.

Almost all maria are on the near side of the Moon, and cover 31% of the surface of the near side[72] compared with 2% of the far side.[130] This is likely due to a concentration of heat-producing elements under the crust on the near side, which would have caused the underlying mantle to heat up, partially melt, rise to the surface and erupt.[77][131][132] Most of the Moon's mare basalts erupted during the Imbrian period, 3.3–3.7 billion years ago, though some being as young as 1.2 billion years[63] and as old as 4.2 billion years.[64]

Old hardened lava flows of Mare Imbrium forming wrinkle ridges

In 2006, a study of Ina, a tiny depression in Lacus Felicitatis, found jagged, relatively dust-free features that, because of the lack of erosion by infalling debris, appeared to be only 2 million years old.[133] Moonquakes and releases of gas indicate continued lunar activity.[133] Evidence of recent lunar volcanism has been identified at 70 irregular mare patches, some less than 50 million years old. This raises the possibility of a much warmer lunar mantle than previously believed, at least on the near side where the deep crust is substantially warmer because of the greater concentration of radioactive elements.[134][135][136][137] Evidence has been found for 2–10 million years old basaltic volcanism within the crater Lowell,[138][139] inside the Orientale basin. Some combination of an initially hotter mantle and local enrichment of heat-producing elements in the mantle could be responsible for prolonged activities on the far side in the Orientale basin.[140][141]

The lighter-colored regions of the Moon are called terrae, or more commonly highlands, because they are higher than most maria. They have been radiometrically dated to having formed 4.4 billion years ago, and may represent plagioclase cumulates of the lunar magma ocean.[64][63] In contrast to Earth, no major lunar mountains are believed to have formed as a result of tectonic events.[142]

The concentration of maria on the near side likely reflects the substantially thicker crust of the highlands of the Far Side, which may have formed in a slow-velocity impact of a second moon of Earth a few tens of millions of years after the Moon's formation.[143][144] Alternatively, it may be a consequence of asymmetrical tidal heating when the Moon was much closer to the Earth.[145]

Impact craters

A gray, many-ridged surface from high above. The largest feature is a circular ringed structure with high walled sides and a lower central peak: the entire surface out to the horizon is filled with similar structures that are smaller and overlapping.
A view of a three kilometer deep larger crater Daedalus on the Moon's far side

A major geologic process that has affected the Moon's surface is impact cratering,[146] with craters formed when asteroids and comets collide with the lunar surface. There are estimated to be roughly 300,000 craters wider than 1 km (0.6 mi) on the Moon's near side.[147] Lunar craters exhibit a variety of forms, depending on their size. In order of increasing diameter, the basic types are simple craters with smooth bowl shaped interiors and upturned rims, complex craters with flat floors, terraced walls and central peaks, peak ring basins, and multi-ring basins with two or more concentric rings of peaks.[148] The vast majority of impact craters are circular, but some, like Cantor and Janssen, have more polygonal outlines, possibly guided by underlying faults and joints. Others, such as the Messier pair, Schiller, and Daniell, are elongated. Such elongation can result from highly oblique impacts, binary asteroid impacts, fragmentation of impactors before surface strike, or closely spaced secondary impacts.[149]

The lunar geologic timescale is based on the most prominent impact events, such as multi-ring formations like Nectaris, Imbrium, and Orientale that are between hundreds and thousands of kilometers in diameter and associated with a broad apron of ejecta deposits that form a regional stratigraphic horizon.[150] The lack of an atmosphere, weather, and recent geological processes mean that many of these craters are well-preserved. Although only a few multi-ring basins have been definitively dated, they are useful for assigning relative ages. Because impact craters accumulate at a nearly constant rate, counting the number of craters per unit area can be used to estimate the age of the surface.[150] However care needs to be exercised with the crater counting technique due to the potential presence of secondary craters. Ejecta from impacts can create secondary craters that often appear in clusters or chains, but can also occur as isolated formations at a considerable distance from the impact. These can resemble primary craters, and may even dominate small crater populations, so their unidentified presence can distort age estimates.[151]

The radiometric ages of impact-melted rocks collected during the Apollo missions cluster between 3.8 and 4.1 billion years old: this has been used to propose a Late Heavy Bombardment period of increased impacts.[152]

High-resolution images from the Lunar Reconnaissance Orbiter in the 2010s show a contemporary crater-production rate significantly higher than was previously estimated. A secondary cratering process caused by distal ejecta is thought to churn the top two centimeters of regolith on a timescale of 81,000 years.[153][154] This rate is 100 times faster than the rate computed from models based solely on direct micrometeorite impacts.[155]

Lunar swirls

Wide angle image of a lunar swirl, the 70 kilometer long Reiner Gamma

Lunar swirls are enigmatic features found across the Moon's surface. They are characterized by a high albedo, appear optically immature (i.e. the optical characteristics of a relatively young regolith), and often have a sinuous shape. Their shape is often accentuated by low albedo regions that wind between the bright swirls. They are located in places with enhanced surface magnetic fields and many are located at the antipodal point of major impacts. Well known swirls include the Reiner Gamma feature and Mare Ingenii. They are hypothesized to be areas that have been partially shielded from the solar wind, resulting in slower space weathering.[156]

Presence of water

Liquid water cannot persist on the lunar surface. When exposed to solar radiation, water quickly decomposes through a process known as photodissociation and is lost to space. However, since the 1960s, scientists have hypothesized that water ice may be deposited by impacting comets or possibly produced by the reaction of oxygen-rich lunar rocks, and hydrogen from solar wind, leaving traces of water which could possibly persist in cold, permanently shadowed craters at either pole on the Moon.[157][158] Computer simulations suggest that up to 14,000 km2 (5,400 sq mi) of the surface may be in permanent shadow.[110] The presence of usable quantities of water on the Moon is an important factor in rendering lunar habitation as a cost-effective plan; the alternative of transporting water from Earth would be prohibitively expensive.[159]

In years since, signatures of water have been found to exist on the lunar surface.[160] In 1994, the bistatic radar experiment located on the Clementine spacecraft, indicated the existence of small, frozen pockets of water close to the surface. However, later radar observations by Arecibo, suggest these findings may rather be rocks ejected from young impact craters.[161] In 1998, the neutron spectrometer on the Lunar Prospector spacecraft showed that high concentrations of hydrogen are present in the first meter of depth in the regolith near the polar regions.[162] Volcanic lava beads, brought back to Earth aboard Apollo 15, showed small amounts of water in their interior.[163]

In 2008, NASA's Moon Mineralogy Mapper equipment on India's Chandrayaan-1 discovered, for the first time, water-rich minerals (shown in blue around a small crater from which they were ejected).

The 2008 Chandrayaan-1 spacecraft has since confirmed the existence of surface water ice, using the on-board Moon Mineralogy Mapper. The spectrometer observed absorption lines common to hydroxyl, in reflected sunlight, providing evidence of large quantities of water ice, on the lunar surface. The spacecraft showed that concentrations may possibly be as high as 1,000 ppm.[164] Using the mapper's reflectance spectra, indirect lighting of areas in shadow confirmed water ice within 20° latitude of both poles in 2018.[165] In 2009, LCROSS sent a 2,300 kg (5,100 lb) impactor into a permanently shadowed polar crater, and detected at least 100 kg (220 lb) of water in a plume of ejected material.[166][167] Another examination of the LCROSS data showed the amount of detected water to be closer to 155 ± 12 kg (342 ± 26 lb).[168]

In May 2011, 615–1410 ppm water in melt inclusions in lunar sample 74220 was reported,[169] the famous high-titanium "orange glass soil" of volcanic origin collected during the Apollo 17 mission in 1972. The inclusions were formed during explosive eruptions on the Moon approximately 3.7 billion years ago. This concentration is comparable with that of magma in Earth's upper mantle. Although of considerable selenological interest, this insight does not mean that water is easily available since the sample originated many kilometers below the surface, and the inclusions are so difficult to access that it took 39 years to find them with a state-of-the-art ion microprobe instrument.

Analysis of the findings of the Moon Mineralogy Mapper (M3) revealed in August 2018 for the first time "definitive evidence" for water-ice on the lunar surface.[170][171] The data revealed the distinct reflective signatures of water-ice, as opposed to dust and other reflective substances.[172] The ice deposits were found on the North and South poles, although it is more abundant in the South, where water is trapped in permanently shadowed craters and crevices, allowing it to persist as ice on the surface since they are shielded from the sun.[170][172]

In October 2020, astronomers reported detecting molecular water on the sunlit surface of the Moon by several independent spacecraft, including the Stratospheric Observatory for Infrared Astronomy (SOFIA).[173][174][175][176]

Earth–Moon system

Orbit

A view of the rotating Earth and the far side of the Moon as the Moon passes on its orbit in between the observing DSCOVR satellite and Earth

The Earth and the Moon form the Earth-Moon satellite system with a shared center of mass, or barycenter. This barycenter is 1,700 km (1,100 mi) (about a quarter of Earth's radius) beneath the Earth's surface.

The Moon's orbit is slightly elliptical, with an orbital eccentricity of 0.055.[1] The semi-major axis of the geocentric lunar orbit, called the lunar distance, is approximately 400,000 km (250,000 miles or 1.28 light-seconds), comparable to going around Earth 9.5 times.[177]

The Moon makes a complete orbit around Earth with respect to the fixed stars, its sidereal period, about once every 27.3 days.[h] However, because the Earth-Moon system moves at the same time in its orbit around the Sun, it takes slightly longer, 29.5 days,[i][72] to return at the same lunar phase, completing a full cycle, as seen from Earth. This synodic period or synodic month is commonly known as the lunar month and is equal to the length of the solar day on the Moon.[178]

Due to tidal locking, the Moon has a 1:1 spin–orbit resonance. This rotationorbit ratio makes the Moon's orbital periods around Earth equal to its corresponding rotation periods. This is the reason for only one side of the Moon, its so-called near side, being visible from Earth. That said, while the movement of the Moon is in resonance, it still is not without nuances such as libration, resulting in slightly changing perspectives, making over time and location on Earth about 59% of the Moon's surface visible from Earth.[179]

Unlike most satellites of other planets, the Moon's orbital plane is closer to the ecliptic plane than to the planet's equatorial plane. The Moon's orbit is subtly perturbed by the Sun and Earth in many small, complex and interacting ways. For example, the plane of the Moon's orbit gradually rotates once every 18.61 years,[180] which affects other aspects of lunar motion. These follow-on effects are mathematically described by Cassini's laws.[181]

Minimum, mean and maximum distances of the Moon from Earth with its angular diameter as seen from Earth's surface, to scale

Tidal effects

Simplified diagram of the Moon's gravity tidal effect on the Earth

The gravitational attraction that Earth and the Moon (as well as the Sun) exert on each other manifests in a slightly greater attraction on the sides closest to each other, resulting in tidal forces. Ocean tides are the most widely experienced result of this, but tidal forces also considerably affect other mechanics of Earth, as well as the Moon and their system.

The lunar solid crust experiences tides of around 10 cm (4 in) amplitude over 27 days, with three components: a fixed one due to Earth, because they are in synchronous rotation, a variable tide due to orbital eccentricity and inclination, and a small varying component from the Sun.[182] The Earth-induced variable component arises from changing distance and libration, a result of the Moon's orbital eccentricity and inclination (if the Moon's orbit were perfectly circular and un-inclined, there would only be solar tides).[182] According to recent research, scientists suggest that the Moon's influence on the Earth may contribute to maintaining Earth's magnetic field.[183]

The cumulative effects of stress built up by these tidal forces produces moonquakes. Moonquakes are much less common and weaker than are earthquakes, although moonquakes can last for up to an hour – significantly longer than terrestrial quakes – because of scattering of the seismic vibrations in the dry fragmented upper crust. The existence of moonquakes was an unexpected discovery from seismometers placed on the Moon by Apollo astronauts from 1969 through 1972.[184]

The most commonly known effect of tidal forces are elevated sea levels called ocean tides.[185] While the Moon exerts most of the tidal forces, the Sun also exerts tidal forces and therefore contributes to the tides as much as 40% of the Moon's tidal force; producing in interplay the spring and neap tides.[185]

The tides are two bulges in the Earth's oceans, one on the side facing the Moon and the other on the side opposite. As the Earth rotates on its axis, one of the ocean bulges (high tide) is held in place "under" the Moon, while another such tide is opposite. As a result, there are two high tides, and two low tides in about 24 hours.[185] Since the Moon is orbiting the Earth in the same direction of the Earth's rotation, the high tides occur about every 12 hours and 25 minutes; the 25 minutes is due to the Moon's time to orbit the Earth.

If the Earth were a water world (one with no continents) it would produce a tide of only one meter, and that tide would be very predictable, but the ocean tides are greatly modified by other effects:

  • the frictional coupling of water to Earth's rotation through the ocean floors
  • the inertia of water's movement
  • ocean basins that grow shallower near land
  • the sloshing of water between different ocean basins[186]

As a result, the timing of the tides at most points on the Earth is a product of observations that are explained, incidentally, by theory.

System evolution

Delays in the tidal peaks of both ocean and solid-body tides cause torque in opposition to the Earth's rotation. This "drains" angular momentum and rotational kinetic energy from Earth's rotation, slowing the Earth's rotation.[185][182] That angular momentum, lost from the Earth, is transferred to the Moon in a process known as tidal acceleration, which lifts the Moon into a higher orbit while lowering orbital speed around the Earth.

Thus the distance between Earth and Moon is increasing, and the Earth's rotation is slowing in reaction.[182] Measurements from laser reflectors left during the Apollo missions (lunar ranging experiments) have found that the Moon's distance increases by 38 mm (1.5 in) per year (roughly the rate at which human fingernails grow).[187][188][189] Atomic clocks show that Earth's day lengthens by about 17 microseconds every year,[190][191][192] slowly increasing the rate at which UTC is adjusted by leap seconds.

This tidal drag makes the rotation of the Earth and the orbital period of the Moon very slowly match. This matching first results in tidally locking the lighter body of the orbital system, as is already the case with the Moon. Theoretically, in 50 billion years,[193] the Earth's rotation will have slowed to the point of matching the Moon's orbital period, causing the Earth to always present the same side to the Moon. However, the Sun will become a red giant, most likely engulfing the Earth-Moon system long before then.[194][195]

If the Earth-Moon system isn't engulfed by the enlarged Sun, the drag from the solar atmosphere can cause the orbit of the Moon to decay. Once the orbit of the Moon closes to a distance of 18,470 km (11,480 mi), it will cross Earth's Roche limit, meaning that tidal interaction with Earth would break apart the Moon, turning it into a ring system. Most of the orbiting rings will begin to decay, and the debris will impact Earth. Hence, even if the Sun does not swallow up Earth, the planet may be left moonless.[196]

Position and appearance

Over one lunar month more than half of the Moon's surface can be seen from Earth's surface.
Libration, the slight variation in the Moon's apparent size and viewing angle over a single lunar month as viewed from somewhere on the Earth's northern hemisphere.

The Moon's highest altitude at culmination varies by its lunar phase, or more correctly its orbital position, and time of the year, or more correctly the position of the Earth's axis. The full moon is highest in the sky during winter and lowest during summer (for each hemisphere respectively), with its altitude changing towards dark moon to the opposite.

At the North and South Poles the Moon is 24 hours above the horizon for two weeks every tropical month (about 27.3 days), comparable to the polar day of the tropical year. Zooplankton in the Arctic use moonlight when the Sun is below the horizon for months on end.[197]

The apparent orientation of the Moon depends on its position in the sky and the hemisphere of the Earth from which it is being viewed. In the northern hemisphere it appears upside down compared to the view from the southern hemisphere.[198] Sometimes the "horns" of a crescent moon appear to be pointing more upwards than sideways. This phenomenon is called a wet moon and occurs more frequently in the tropics.[199]

The distance between the Moon and Earth varies from around 356,400 km (221,500 mi) (perigee) to 406,700 km (252,700 mi) (apogee), making the Moon's distance and apparent size fluctuate up to 14%.[200][201] On average the Moon's angular diameter is about 0.52°, roughly the same apparent size as the Sun (see § Eclipses). In addition, a purely psychological effect, known as the Moon illusion, makes the Moon appear larger when close to the horizon.[202]

Despite the Moon's tidal locking, the effect of libration makes about 59% of the Moon's surface visible from Earth over the course of one month.[179][72]

Rotation

Comparison between the Moon on the left, rotating tidally locked (correct), and with the Moon on the right, without rotation (incorrect)

The tidally locked synchronous rotation of the Moon as it orbits the Earth results in it always keeping nearly the same face turned towards the planet. The side of the Moon that faces Earth is called the near side, and the opposite the far side. The far side is often inaccurately called the "dark side", but it is in fact illuminated as often as the near side: once every 29.5 Earth days. During dark moon to new moon, the near side is dark.[203]

The Moon originally rotated at a faster rate, but early in its history its rotation slowed and became tidally locked in this orientation as a result of frictional effects associated with tidal deformations caused by Earth.[204] With time, the energy of rotation of the Moon on its axis was dissipated as heat, until there was no rotation of the Moon relative to Earth. In 2016, planetary scientists using data collected on the 1998-99 NASA Lunar Prospector mission, found two hydrogen-rich areas (most likely former water ice) on opposite sides of the Moon. It is speculated that these patches were the poles of the Moon billions of years ago before it was tidally locked to Earth.[205]

Illumination and phases

The monthly changes in the angle between the direction of sunlight and view from Earth, and the phases of the Moon that result, as viewed from the Northern Hemisphere. The Earth–Moon distance is not to scale.

Half of the Moon's surface is always illuminated by the Sun (except during a lunar eclipse). Earth also reflects light onto the Moon, observable at times as Earthlight when it is reflected back to Earth from areas of the near side of the Moon that are not illuminated by the Sun.

Since the Moon's axial tilt with respect to the ecliptic is 1.5427°, in every draconic year (346.62 days) the Sun moves from being 1.5427° north of the lunar equator to being 1.5427° south of it and then back, just as on Earth the Sun moves from the Tropic of Cancer to the Tropic of Capricorn and back once every tropical year. The poles of the Moon are therefore in the dark for half a draconic year (or with only part of the Sun visible) and then lit for half a draconic year. The amount of sunlight falling on horizontal areas near the poles depends on the altitude angle of the Sun. But these "seasons" have little effect in more equatorial areas.

With the different positions of the Moon, different areas of it are illuminated by the Sun. This illumination of different lunar areas, as viewed from Earth, produces the different lunar phases during the synodic month. The phase is equal to the area of the visible lunar sphere that is illuminated by the Sun. This area or degree of illumination is given by , where is the elongation (i.e., the angle between Moon, the observer on Earth, and the Sun).

Brightness and apparent size of the Moon changes also due to its elliptic orbit around Earth. At perigee (closest), since the Moon is up to 14% closer to Earth than at apogee (most distant), it subtends a solid angle which is up to 30% larger. Consequently, given the same phase, the Moon's brightness also varies by up to 30% between apogee and perigee.[206] A full (or new) moon at such a position is called a supermoon.[200][201][207]

Observational phenomena

There has been historical controversy over whether observed features on the Moon's surface change over time. Today, many of these claims are thought to be illusory, resulting from observation under different lighting conditions, poor astronomical seeing, or inadequate drawings. However, outgassing does occasionally occur and could be responsible for a minor percentage of the reported lunar transient phenomena. Recently, it has been suggested that a roughly 3 km (1.9 mi) diameter region of the lunar surface was modified by a gas release event about a million years ago.[208][209]

Albedo and color

The changing apparent color of the Moon, filtered by Earth's atmosphere

The Moon has an exceptionally low albedo, giving it a reflectance that is slightly brighter than that of worn asphalt. Despite this, it is the brightest object in the sky after the Sun.[72][j] This is due partly to the brightness enhancement of the opposition surge; the Moon at quarter phase is only one-tenth as bright, rather than half as bright, as at full moon.[210] Additionally, color constancy in the visual system recalibrates the relations between the colors of an object and its surroundings, and because the surrounding sky is comparatively dark, the sunlit Moon is perceived as a bright object. The edges of the full moon seem as bright as the center, without limb darkening, because of the reflective properties of lunar soil, which retroreflects light more towards the Sun than in other directions. The Moon's color depends on the light the Moon reflects, which in turn depends on the Moon's surface and its features, having for example large darker regions. In general the lunar surface reflects a brown-tinged gray light.[211]

At times, the Moon can appear red or blue. It may appear red during a lunar eclipse, because of the red spectrum of the Sun's light being refracted onto the Moon by Earth's atmosphere. Because of this red color, lunar eclipses are also sometimes called blood moons. The Moon can also seem red when it appears at low angles and through a thick atmosphere.

The Moon may appear blue depending on the presence of certain particles in the air,[211] such as volcanic particles,[212] in which case it can be called a blue moon.

Because the words "red moon" and "blue moon" can also be used to refer to specific full moons of the year, they do not always refer to the presence of red or blue moonlight.

Eclipses

A solar eclipse causes the Sun to be covered, revealing the white corona.
The Moon, tinted reddish, during a lunar eclipse

Eclipses only occur when the Sun, Earth, and Moon are all in a straight line (termed "syzygy"). Solar eclipses occur at new moon, when the Moon is between the Sun and Earth. In contrast, lunar eclipses occur at full moon, when Earth is between the Sun and Moon. The apparent size of the Moon is roughly the same as that of the Sun, with both being viewed at close to one-half a degree wide. The Sun is much larger than the Moon but it is the vastly greater distance that gives it the same apparent size as the much closer and much smaller Moon from the perspective of Earth. The variations in apparent size, due to the non-circular orbits, are nearly the same as well, though occurring in different cycles. This makes possible both total (with the Moon appearing larger than the Sun) and annular (with the Moon appearing smaller than the Sun) solar eclipses.[213] In a total eclipse, the Moon completely covers the disc of the Sun and the solar corona becomes visible to the naked eye.

Because the distance between the Moon and Earth is very slowly increasing over time,[185] the angular diameter of the Moon is decreasing. As it evolves toward becoming a red giant, the size of the Sun, and its apparent diameter in the sky, are slowly increasing.[k] The combination of these two changes means that hundreds of millions of years ago, the Moon would always completely cover the Sun on solar eclipses, and no annular eclipses were possible. Likewise, hundreds of millions of years in the future, the Moon will no longer cover the Sun completely, and total solar eclipses will not occur.[214]

As the Moon's orbit around Earth is inclined by about 5.145° (5° 9') to the orbit of Earth around the Sun, eclipses do not occur at every full and new moon. For an eclipse to occur, the Moon must be near the intersection of the two orbital planes.[215] The periodicity and recurrence of eclipses of the Sun by the Moon, and of the Moon by Earth, is described by the saros, which has a period of approximately 18 years.[216]

Because the Moon continuously blocks the view of a half-degree-wide circular area of the sky,[l][217] the related phenomenon of occultation occurs when a bright star or planet passes behind the Moon and is occulted: hidden from view. In this way, a solar eclipse is an occultation of the Sun. Because the Moon is comparatively close to Earth, occultations of individual stars are not visible everywhere on the planet, nor at the same time. Because of the precession of the lunar orbit, each year different stars are occulted.[218]

History of exploration and human presence

Pre-telescopic observation (before 1609)

It is believed by some that the oldest cave paintings from up to 40,000 BP of bulls and geometric shapes,[219] or 20–30,000 year old tally sticks were used to observe the phases of the Moon, keeping time using the waxing and waning of the Moon's phases.[220] One of the earliest-discovered possible depictions of the Moon is a 3,000 BCE rock carving Orthostat 47 at Knowth, Ireland.[221][222] Lunar deities like Nanna/Sin featuring crescents are found since the 3rd millennium BCE.[223] Though the oldest found and identified astronomical depiction of the Moon is the Nebra sky disc from c. 1800–1600 BCE.[224][225]

The Nebra sky disc (c. 1800–1600 BCE) with the Moon as a crescent, and gold strips on the side of the disc marking the summer and winter solstices,[226][227] and the top representing the horizon[228] and north.

The ancient Greek philosopher Anaxagoras (d. 428 BC) reasoned that the Sun and Moon were both giant spherical rocks, and that the latter reflected the light of the former.[229][230]: 227  Elsewhere in the 5th century BC to 4th century BC, Babylonian astronomers had recorded the 18-year Saros cycle of lunar eclipses,[231] and Indian astronomers had described the Moon's monthly elongation.[232] The Chinese astronomer Shi Shen (fl. 4th century BC) gave instructions for predicting solar and lunar eclipses.[230]: 411 

In Aristotle's (384–322 BC) description of the universe, the Moon marked the boundary between the spheres of the mutable elements (earth, water, air and fire), and the imperishable stars of aether, an influential philosophy that would dominate for centuries.[233] Archimedes (287–212 BC) designed a planetarium that could calculate the motions of the Moon and other objects in the Solar System.[234] In the 2nd century BC, Seleucus of Seleucia correctly thought that tides were due to the attraction of the Moon, and that their height depends on the Moon's position relative to the Sun.[235] In the same century, Aristarchus computed the size and distance of the Moon from Earth, obtaining a value of about twenty times the radius of Earth for the distance.

The Chinese of the Han dynasty believed the Moon to be energy equated to qi and their 'radiating influence' theory recognized that the light of the Moon was merely a reflection of the Sun; Jing Fang (78–37 BC) noted the sphericity of the Moon.[230]: 413–414  Ptolemy (90–168 AD) greatly improved on the numbers of Aristarchus, calculating a mean distance of 59 times Earth's radius and a diameter of 0.292 Earth diameters, close to the correct values of about 60 and 0.273 respectively.[236] In the 2nd century AD, Lucian wrote the novel A True Story, in which the heroes travel to the Moon and meet its inhabitants. In 510 AD, the Indian astronomer Aryabhata mentioned in his Aryabhatiya that reflected sunlight is the cause of the shining of the Moon.[237][238] The astronomer and physicist Ibn al-Haytham (965–1039) found that sunlight was not reflected from the Moon like a mirror, but that light was emitted from every part of the Moon's sunlit surface in all directions.[239] Shen Kuo (1031–1095) of the Song dynasty created an allegory equating the waxing and waning of the Moon to a round ball of reflective silver that, when doused with white powder and viewed from the side, would appear to be a crescent.[230]: 415–416  During the Middle Ages, before the invention of the telescope, the Moon was increasingly recognized as a sphere, though many believed that it was "perfectly smooth".[240]

Telescopic exploration (1609–1959)

Galileo's sketches of the Moon from the ground-breaking Sidereus Nuncius (1610), publishing among other findings the first descriptions of the Moon's topography

In 1609, Galileo Galilei used an early telescope to make drawings of the Moon for his book Sidereus Nuncius, and deduced that it was not smooth but had mountains and craters. Thomas Harriot had made, but not published such drawings a few months earlier.

Telescopic mapping of the Moon followed: later in the 17th century, the efforts of Giovanni Battista Riccioli and Francesco Maria Grimaldi led to the system of naming of lunar features in use today. The more exact 1834–1836 Mappa Selenographica of Wilhelm Beer and Johann Heinrich von Mädler, and their associated 1837 book Der Mond, the first trigonometrically accurate study of lunar features, included the heights of more than a thousand mountains, and introduced the study of the Moon at accuracies possible in earthly geography.[241] Lunar craters, first noted by Galileo, were thought to be volcanic until the 1870s proposal of Richard Proctor that they were formed by collisions.[72] This view gained support in 1892 from the experimentation of geologist Grove Karl Gilbert, and from comparative studies from 1920 to the 1940s,[242] leading to the development of lunar stratigraphy, which by the 1950s was becoming a new and growing branch of astrogeology.[72]

First missions to the Moon (1959–1976)

After World War II the first launch systems were developed and by the end of the 1950s they reached capabilities that allowed the Soviet Union and the United States to launch spacecraft into space. The Cold War fueled a closely followed development of launch systems by the two states, resulting in the so-called Space Race and its later phase the Moon Race, accelerating efforts and interest in exploration of the Moon.

First view of the far side of the Moon, taken by Luna 3, October 7, 1959. Clearly visible is Mare Moscoviense (top right) and a mare triplet of Mare Crisium, Mare Marginis and Mare Smythii (left center).

After the first spaceflight of Sputnik 1 in 1957 during International Geophysical Year the spacecraft of the Soviet Union's Luna program were the first to accomplish a number of goals. Following three unnamed failed missions in 1958,[243] the first human-made object Luna 1 escaped Earth's gravity and passed near the Moon in 1959. Later that year the first human-made object Luna 2 reached the Moon's surface by intentionally impacting. By the end of the year Luna 3 reached as the first human-made object the normally occluded far side of the Moon, taking the first photographs of it. The first spacecraft to perform a successful lunar soft landing was Luna 9 and the first vehicle to orbit the Moon was Luna 10, both in 1966.[72]

The small blue-white semicircle of Earth, almost glowing with color in the blackness of space, rising over the limb of the desolate, cratered surface of the Moon.
Earthrise, the first color image of Earth taken by a human from the Moon, during Apollo 8 (1968) the first time a crewed spacecraft left Earth orbit and reached another astronomical body

Following President John F. Kennedy's 1961 commitment to a crewed Moon landing before the end of the decade, the United States, under NASA leadership, launched a series of uncrewed probes to develop an understanding of the lunar surface in preparation for human missions: the Jet Propulsion Laboratory's Ranger program, the Lunar Orbiter program and the Surveyor program. The crewed Apollo program was developed in parallel; after a series of uncrewed and crewed tests of the Apollo spacecraft in Earth orbit, and spurred on by a potential Soviet lunar human landing, in 1968 Apollo 8 made the first human mission to lunar orbit (the first Earthlings, two tortoises, had circled the Moon three months earlier on the Soviet Union's Zond 5, followed by turtles on Zond 6).

The first time a person landed on the Moon and any extraterrestrial body was when Neil Armstrong, the commander of the American mission Apollo 11, set foot on the Moon at 02:56 UTC on July 21, 1969.[244] Considered the culmination of the Space Race,[245] an estimated 500 million people worldwide watched the transmission by the Apollo TV camera, the largest television audience for a live broadcast at that time.[246][247] While at the same time another mission, the robotic sample return mission Luna 15 by the Soviet Union had been in orbit around the Moon, becoming together with Apollo 11 the first ever case of two extraterrestrial missions being conducted at the same time.

The Apollo missions 11 to 17 (except Apollo 13, which aborted its planned lunar landing) removed 380.05 kilograms (837.87 lb) of lunar rock and soil in 2,196 separate samples.[248] Scientific instrument packages were installed on the lunar surface during all the Apollo landings. Long-lived instrument stations, including heat flow probes, seismometers, and magnetometers, were installed at the Apollo 12, 14, 15, 16, and 17 landing sites. Direct transmission of data to Earth concluded in late 1977 because of budgetary considerations,[249][250] but as the stations' lunar laser ranging corner-cube retroreflector arrays are passive instruments, they are still being used.[251] Apollo 17 in 1972 remains the last crewed mission to the Moon. Explorer 49 in 1973 was the last dedicated U.S. probe to the Moon until the 1990s.

The Soviet Union continued sending robotic missions to the Moon until 1976, deploying in 1970 with Luna 17 the first remote controlled rover Lunokhod 1 on an extraterrestrial surface, and collecting and returning 0.3 kg of rock and soil samples with three Luna sample return missions (Luna 16 in 1970, Luna 20 in 1972, and Luna 24 in 1976).[252]

Moon Treaty and explorational absence (1976–1990)

A near lunar quietude of fourteen years followed the last Soviet mission to the Moon of 1976. Astronautics had shifted its focus towards the exploration of the inner (e.g. Venera program) and outer (e.g. Pioneer 10, 1972) Solar System planets, but also towards Earth orbit, developing and continuously operating, beside communication satellites, Earth observation satellites (e.g. Landsat program, 1972), space telescopes and particularly space stations (e.g. Salyut program, 1971).

The until 1979 negotiated Moon treaty, with its ratification in 1984 by its few signatories was about the only major activity regarding the Moon until 1990.

Renewed exploration (1990–present)

Map of all soft landing sites on the near side of the Moon (2024)

In 1990 Hiten-Hagoromo,[253] the first dedicated lunar mission since 1976, reached the Moon. Sent by Japan, it became the first mission that was not a Soviet Union or U.S. mission to the Moon.

In 1994, the U.S. dedicated a mission to fly a spacecraft (Clementine) to the Moon again for the first time since 1973. This mission obtained the first near-global topographic map of the Moon, and the first global multispectral images of the lunar surface.[254] In 1998, this was followed by the Lunar Prospector mission, whose instruments indicated the presence of excess hydrogen at the lunar poles, which is likely to have been caused by the presence of water ice in the upper few meters of the regolith within permanently shadowed craters.[255]

The next years saw a row of first missions to the Moon by a new group of states actively exploring the Moon. Between 2004 and 2006 the first spacecraft by the European Space Agency (ESA) (SMART-1) reached the Moon, recording the first detailed survey of chemical elements on the lunar surface.[256] The Chinese Lunar Exploration Program reached the Moon for the first time with the orbiter Chang'e 1 (2007–2009),[257] obtaining a full image map of the Moon. India reached, orbited and impacted the Moon in 2008 for the first time with its Chandrayaan-1 and Moon Impact Probe, becoming the fifth and sixth state to do so, creating a high-resolution chemical, mineralogical and photo-geological map of the lunar surface, and confirming the presence of water molecules in lunar soil.[258]

The U.S. launched the Lunar Reconnaissance Orbiter (LRO) and the LCROSS impactor on June 18, 2009. LCROSS completed its mission by making a planned and widely observed impact in the crater Cabeus on October 9, 2009,[259] whereas LRO is currently in operation, obtaining precise lunar altimetry and high-resolution imagery.

China continued its lunar program in 2010 with Chang'e 2, mapping the surface at a higher resolution over an eight-month period, and in 2013 with Chang'e 3, a lunar lander along with a lunar rover named Yutu (Chinese: 玉兔; lit. 'Jade Rabbit'). This was the first lunar rover mission since Lunokhod 2 in 1973 and the first lunar soft landing since Luna 24 in 1976, making China the third country to achieve this.

In 2014 the first privately funded probe, the Manfred Memorial Moon Mission, reached the Moon.

Another Chinese rover mission, Chang'e 4, achieved the first landing on the Moon's far side in early 2019.[260]

Also in 2019, India successfully sent its second probe, Chandrayaan-2 to the Moon.

In 2020, China carried out its first robotic sample return mission (Chang'e 5), bringing back 1,731 grams of lunar material to Earth.[261]

The U.S. developed plans for returning to the Moon beginning in 2004,[262] and with the signing of the U.S.-led Artemis Accords in 2020, the Artemis program aims to return the astronauts to the Moon in the 2020s.[263] The Accords have been joined by a growing number of countries. The introduction of the Artemis Accords has fueled a renewed discussion about the international framework and cooperation of lunar activity, building on the Moon Treaty and the ESA-led Moon Village concept.[264][265][266]

2023 and 2024 India and Japan became the fourth and fifth country to soft land a spacecraft on the Moon, following the Soviet Union and United States in the 1960s, and China in the 2010s.[267] Notably, Japan's spacecraft, the Smart Lander for Investigating Moon, survived 3 lunar nights.[268] The IM-1 lander became the first commercially built lander to land on the Moon in 2024.[269]

China launched the Chang'e 6 on May 3, 2024, which conducted another lunar sample return from the far side of the Moon.[270] It also carried a Chinese rover to conduct infrared spectroscopy of lunar surface.[271] Pakistan sent a lunar orbiter called ICUBE-Q along with Chang'e 6.[272]

Nova-C 2, iSpace Lander and Blue Ghost are all planned to launch to the Moon in 2024.

Future

Artemis II crew, with the first woman, person of color and non-US citizen astronaut planned to go to the Moon, scheduled for 2025, returning humans to the Moon for the first time since Apollo 17 in 1972. Clockwise from left: Koch, Glover, Hansen and Wiseman.

Beside the progressing Artemis program and supporting Commercial Lunar Payload Services, leading an international and commercial crewed opening up of the Moon and sending the first woman, person of color and non-US citizen to the Moon in the 2020s,[273] China is continuing its ambitious Chang'e program, having announced with Russia's struggling Luna-Glob program joint missions.[274][275] Both the Chinese and US lunar programs have the goal to establish in the 2030s a lunar base with their international partners, though the US and its partners will first establish an orbital Lunar Gateway station in the 2020s, from which Artemis missions will land the Human Landing System to set up temporary surface camps.

While the Apollo missions were explorational in nature, the Artemis program plans to establish a more permanent presence. To this end, NASA is partnering with industry leaders to establish key elements such as modern communication infrastructure. A 4G connectivity demonstration is to be launched aboard an Intuitive Machines Nova-C lander in 2024.[276] Another focus is on in situ resource utilization, which is a key part of the DARPA lunar programs. DARPA has requested that industry partners develop a 10–year lunar architecture plan to enable the beginning of a lunar economy.[277]

Human presence

Humans last landed on the Moon during the Apollo Program, a series of crewed exploration missions carried out from 1969 to 1972. Lunar orbit has seen uninterrupted presence of orbiters since 2006, performing mainly lunar observation and providing relayed communication for robotic missions on the lunar surface.

Lunar orbits and orbits around Earth–Moon Lagrange points are used to establish a near-lunar infrastructure to enable increasing human activity in cislunar space as well as on the Moon's surface. Missions at the far side of the Moon or the lunar north and south polar regions need spacecraft with special orbits, such as the Queqiao and Queqiao-2 relay satellite or the planned first extraterrestrial space station, the Lunar Gateway.[278][279]

Human impact

Artifacts of human activity, Apollo 17's Lunar Surface Experiments Package[280]

While the Moon has the lowest planetary protection target-categorization, its degradation as a pristine body and scientific place has been discussed.[281] If there is astronomy performed from the Moon, it will need to be free from any physical and radio pollution. While the Moon has no significant atmosphere, traffic and impacts on the Moon causes clouds of dust that can spread far and possibly contaminate the original state of the Moon and its special scientific content.[282] Scholar Alice Gorman asserts that, although the Moon is inhospitable, it is not dead, and that sustainable human activity would require treating the Moon's ecology as a co-participant.[283]

The so-called "Tardigrade affair" of the 2019 crashed Beresheet lander and its carrying of tardigrades has been discussed as an example for lacking measures and lacking international regulation for planetary protection.[284]

Space debris beyond Earth around the Moon has been considered as a future challenge with increasing numbers of missions to the Moon, particularly as a danger for such missions.[285][286] As such lunar waste management has been raised as an issue which future lunar missions, particularly on the surface, need to tackle.[287][288]

Human remains have been transported to the Moon, including by private companies such as Celestis and Elysium Space. Because the Moon has been sacred or significant to many cultures, the practice of space burials have attracted criticism from indigenous peoples leaders. For example, then–Navajo Nation president Albert Hale criticized NASA for sending the cremated ashes of scientist Eugene Shoemaker to the Moon in 1998.[289][290]

Beside the remains of human activity on the Moon, there have been some intended permanent installations like the Moon Museum art piece, Apollo 11 goodwill messages, six lunar plaques, the Fallen Astronaut memorial, and other artifacts.[280]

Longterm missions continuing to be active are some orbiters such as the 2009-launched Lunar Reconnaissance Orbiter surveilling the Moon for future missions, as well as some Landers such as the 2013-launched Chang'e 3 with its Lunar Ultraviolet Telescope still operational.[291] Five retroreflectors have been installed on the Moon since the 1970s and since used for accurate measurements of the physical librations through laser ranging to the Moon.

There are several missions by different agencies and companies planned to establish a longterm human presence on the Moon, with the Lunar Gateway as the currently most advanced project as part of the Artemis program.

Astronomy from the Moon

The LCRT concept for a radio telescope on the Moon

The Moon is recognized as an excellent site for telescopes.[292] It is relatively nearby; certain craters near the poles are permanently dark and cold and especially useful for infrared telescopes; and radio telescopes on the far side would be shielded from the radio chatter of Earth.[293] The lunar soil, although it poses a problem for any moving parts of telescopes, can be mixed with carbon nanotubes and epoxies and employed in the construction of mirrors up to 50 meters in diameter.[294] A lunar zenith telescope can be made cheaply with an ionic liquid.[295]

In April 1972, the Apollo 16 mission recorded various astronomical photos and spectra in ultraviolet with the Far Ultraviolet Camera/Spectrograph.[296]

The Moon has been also a site of Earth observation, particularly culturally as in the 1968 photograph called Earthrise, taken by Bill Anders of Apollo 8. The Earth appears in the Moon's sky with an apparent size of 1° 48 to 2°,[297] three to four times the size of the Moon or Sun in Earth's sky, or about the apparent width of two little fingers at an arm's length away.

Living on the Moon

Astronaut Buzz Aldrin in life-supporting suit looking back at the first lunar habitat and base, the Lunar Module Eagle of Tranquility Base, during Apollo 11 (1969), the first crewed Moon landing

The only instances of humans living on the Moon have taken place in an Apollo Lunar Module for several days at a time (for example, during the Apollo 17 mission).[298] One challenge to astronauts during their stay on the surface is that lunar dust sticks to their suits and is carried into their quarters. Astronauts could taste and smell the dust, which smells like gunpowder and was called the "Apollo aroma".[299] This fine lunar dust can cause health issues.[299]

In 2019, at least one plant seed sprouted in an experiment on the Chang'e 4 lander. It was carried from Earth along with other small life in its Lunar Micro Ecosystem.[300]

Although Luna landers scattered pennants of the Soviet Union on the Moon, and U.S. flags were symbolically planted at their landing sites by the Apollo astronauts, no nation claims ownership of any part of the Moon's surface.[301] Likewise no private ownership of parts of the Moon, or as a whole, is considered credible.[302][303][304]

The 1967 Outer Space Treaty defines the Moon and all outer space as the "province of all mankind".[301] It restricts the use of the Moon to peaceful purposes, explicitly banning military installations and weapons of mass destruction.[305] A majority of countries are parties of this treaty.[306] The 1979 Moon Agreement was created to elaborate, and restrict the exploitation of the Moon's resources by any single nation, leaving it to a yet unspecified international regulatory regime.[307] As of January 2020, it has been signed and ratified by 18 nations,[308] none of which have human spaceflight capabilities.

Since 2020, countries have joined the U.S. in their Artemis Accords, which are challenging the treaty. The U.S. has furthermore emphasized in a presidential executive order ("Encouraging International Support for the Recovery and Use of Space Resources.") that "the United States does not view outer space as a 'global commons'" and calls the Moon Agreement "a failed attempt at constraining free enterprise."[309][310]

With Australia signing and ratifying both the Moon Treaty in 1986 as well as the Artemis Accords in 2020, there has been a discussion if they can be harmonized.[265] In this light an Implementation Agreement for the Moon Treaty has been advocated for, as a way to compensate for the shortcomings of the Moon Treaty and to harmonize it with other laws and agreements such as the Artemis Accords, allowing it to be more widely accepted.[264][266]

In the face of such increasing commercial and national interest, particularly prospecting territories, U.S. lawmakers have introduced in late 2020 specific regulation for the conservation of historic landing sites[311] and interest groups have argued for making such sites World Heritage Sites[312] and zones of scientific value protected zones, all of which add to the legal availability and territorialization of the Moon.[284]

In 2021, the Declaration of the Rights of the Moon[313] was created by a group of "lawyers, space archaeologists and concerned citizens", drawing on precedents in the Rights of Nature movement and the concept of legal personality for non-human entities in space.[314][315]

Coordination and regulation

Increasing human activity at the Moon has raised the need for coordination to safeguard international and commercial lunar activity. Issues from cooperation to mere coordination, through for example the development of a shared Lunar time, have been raised.

In particular the establishment of an international or United Nations regulatory regime for lunar human activity has been called for by the Moon Treaty and suggested through an Implementation Agreement,[264][266] but remains contentious. Current lunar programs are multilateral, with the US-led Artemis program and the China-led International Lunar Research Station. For broader international cooperation and coordination the International Lunar Exploration Working Group (ILEWG), the Moon Village Association (MVA) and more generally the International Space Exploration Coordination Group (ISECG) has been established.

In culture and life

Timekeeping

The Venus of Laussel (c. 25,000 BP) holding a crescent shaped horn. The 13 notches on the horn may symbolize the average number of days from menstruation to an ovulation, or the approximate number of full menstrual cycles and lunar cycles per year (although these two phenomena are unrelated).[316][317]

Since pre-historic times people have taken note of the Moon's phases and its waxing and waning cycle, and used it to keep record of time. Tally sticks, notched bones dating as far back as 20–30,000 years ago, are believed by some to mark the phases of the Moon.[220][318][319] The counting of the days between the Moon's phases gave eventually rise to generalized time periods of lunar cycles as months, and possibly of its phases as weeks.[320]

The words for the month in a range of different languages carry this relation between the period of the month and the Moon etymologically. The English month as well as moon, and its cognates in other Indo-European languages (e.g. the Latin mensis and Ancient Greek μείς (meis) or μήν (mēn), meaning "month")[321][322][323][324] stem from the Proto-Indo-European (PIE) root of moon, *méh1nōt, derived from the PIE verbal root *meh1-, "to measure", "indicat[ing] a functional conception of the Moon, i.e. marker of the month" (cf. the English words measure and menstrual).[325][326][327] To give another example from a different language family, the Chinese language uses the same word () for moon as well as for month, which furthermore can be found in the symbols for the word week (星期).

This lunar timekeeping gave rise to the historically dominant, but varied, lunisolar calendars. The 7th-century Islamic calendar is an example of a purely lunar calendar, where months are traditionally determined by the visual sighting of the hilal, or earliest crescent moon, over the horizon.[328]

Of particular significance has been the occasion of full moon, highlighted and celebrated in a range of calendars and cultures, an example being the Buddhist Vesak. The full moon around the southern or northern autumnal equinox is often called the harvest moon and is celebrated with festivities such as the Harvest Moon Festival of the Chinese lunar calendar, its second most important celebration after the Chinese lunisolar Lunar New Year.[329]

Furthermore, association of time with the Moon can also be found in religion, such as the ancient Egyptian temporal and lunar deity Khonsu.

Cultural representation

Recurring lunar aspects of lunar deities
Sumerian cylinder seal and impression, dated c. 2100 BC, of Ḫašḫamer, ensi (governor) of Iškun-Sin c. 2100 BC. The seated figure is probably king Ur-Nammu, bestowing the governorship on Ḫašḫamer, who is led before him by Lamma (protective goddess).[330]
The crescent of Nanna/Sîn, c. 2100 BC
Luna on the Parabiago plate (2nd–5th century), featuring the crescent crown, chariot and velificatio as lunar aspect found in different cultures.
Crescent headgear, chariot and velificatio of Luna, 2nd–5th century
Rabbits are in a range of cultures identified with the Moon, from China to the Indigenous peoples of the Americas, as with the rabbit (on the left) of the Maya moon goddess (6th–9th century).
A Moon rabbit of the Mayan moon goddess, 6th–9th century

Since prehistoric times humans have depicted and later described their perception of the Moon and its importance for them and their cosmologies. It has been characterized and associated in many different ways, from having a spirit or being a deity, and an aspect thereof or an aspect in astrology.

Crescent

For the representation of the Moon, especially its lunar phases, the crescent (🌙) has been a recurring symbol in a range of cultures since at least 3,000 BCE or possibly earlier with bull horns dating to the earliest cave paintings at 40,000 BP.[225][219] In writing systems such as Chinese the crescent has developed into the symbol , the word for Moon, and in ancient Egyptian it was the symbol 𓇹, meaning Moon and spelled like the ancient Egyptian lunar deity Iah,[331] which the other ancient Egyptian lunar deities Khonsu and Thoth were associated with.

Iconographically the crescent was used in Mesopotamia as the primary symbol of Nanna/Sîn,[223] the ancient Sumerian lunar deity,[332][223] who was the father of Inanna/Ishtar, the goddess of the planet Venus (symbolized as the eight pointed Star of Ishtar),[332][223] and Utu/Shamash, the god of the Sun (symbolized as a disc, optionally with eight rays),[332][223] all three often depicted next to each other. Nanna/Sîn is, like some other lunar deities, for example Iah and Khonsu of ancient Egypt, Mene/Selene of ancient Greece and Luna of ancient Rome, depicted as a horned deity, featuring crescent shaped headgears or crowns.[333][334]

The particular arrangement of the crescent with a star known as the star and crescent (☪️) goes back to the Bronze Age, representing either the Sun and Moon, or the Moon and the planet Venus, in combination. It came to represent the selene goddess Artemis, and via the patronage of Hecate, which as triple deity under the epithet trimorphos/trivia included aspects of Artemis/Diana, came to be used as a symbol of Byzantium, with Virgin Mary (Queen of Heaven) later taking her place, becoming depicted in Marian veneration on a crescent and adorned with stars. Since then the heraldric use of the star and crescent proliferated, Byzantium's symbolism possibly influencing the development of the Ottoman flag, specifically the combination of the Turkish crescent with a star,[335] and becoming a popular symbol for Islam (as the hilal of the Islamic calendar) and for a range of nations.[336]

Other association

The features of the Moon, the contrasting brighter highlands and darker maria, have been seen by different cultures forming abstract shapes. Such shapes are among others the Man in the Moon (e.g. Coyolxāuhqui) or the Moon Rabbit (e.g. the Chinese Tu'er Ye or in Indigenous American mythologies the aspect of the Mayan Moon goddess, from which possibly Awilix is derived, or of Metztli/Tēcciztēcatl).[330]

Occasionally some lunar deities have been also depicted driving a chariot across the sky, such as the Hindu Chandra/Soma, the Greek Artemis, which is associated with Selene, or Luna, Selene's ancient Roman equivalent.

Color and material wise the Moon has been associated in Western alchemy with silver, while gold is associated with the Sun.[337]

Through a miracle, the so-called splitting of the Moon (Arabic: انشقاق القمر) in Islam, association with the Moon applies also to Muhammad.[338]

Modern culture representation

The Moon is prominently featured in Vincent van Gogh's 1889 painting, The Starry Night.[339]
An iconic image of the Man in the Moon from the first science-fiction film set in space, A Trip to the Moon (1902, Georges Méliès), inspired by a history of literature about going to the Moon.

The perception of the Moon in modern times has been informed by telescope enabled modern astronomy and later by spaceflight enabled actual human activity at the Moon, particularly the culturally impactful lunar landings. These new insights inspired cultural references, connecting romantic reflections about the Moon[340] and speculative fiction such as science-fiction dealing with the Moon.[339][341]

Contemporarily the Moon has been seen as a place for economic expansion into space, with missions prospecting for lunar resources. This has been accompanied with renewed public and critical reflection on humanity's cultural and legal relation to the celestial body, especially regarding colonialism,[284] as in the 1970 poem "Whitey on the Moon". In this light the Moon's nature has been invoked,[313] particularly for lunar conservation[286] and as a common.[342][307][315]

In 2021 20 July, the date of the first crewed Moon landing, became the annual International Moon Day.[343]

Lunar effect

The lunar effect is a purported unproven correlation between specific stages of the roughly 29.5-day lunar cycle and behavior and physiological changes in living beings on Earth, including humans. The Moon has long been associated with insanity and irrationality; the words lunacy and lunatic are derived from the Latin name for the Moon, Luna. Philosophers Aristotle and Pliny the Elder argued that the full moon induced insanity in susceptible individuals, believing that the brain, which is mostly water, must be affected by the Moon and its power over the tides, but the Moon's gravity is too slight to affect any single person.[344] Even today, people who believe in a lunar effect claim that admissions to psychiatric hospitals, traffic accidents, homicides or suicides increase during a full moon, but dozens of studies invalidate these claims.[344][345][346][347][348]

See also

Explanatory notes

  1. ^ Between 18.29° and 28.58° to Earth's equator[1]
  2. ^ There are a number of near-Earth asteroids, including 3753 Cruithne, that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term (Morais et al, 2002). These are quasi-satellites – they are not moons as they do not orbit Earth. For more information, see Other moons of Earth.
  3. ^ The maximum value is given based on scaling of the brightness from the value of −12.74 given for an equator to Moon-centre distance of 378 000 km in the NASA factsheet reference to the minimum Earth–Moon distance given there, after the latter is corrected for Earth's equatorial radius of 6 378 km, giving 350 600 km. The minimum value (for a distant new moon) is based on a similar scaling using the maximum Earth–Moon distance of 407 000 km (given in the factsheet) and by calculating the brightness of the earthshine onto such a new moon. The brightness of the earthshine is [ Earth albedo × (Earth radius / Radius of Moon's orbit)2 ] relative to the direct solar illumination that occurs for a full moon. (Earth albedo = 0.367; Earth radius = (polar radius × equatorial radius)½ = 6 367 km.)
  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 arcseconds. The same fact sheet gives extreme Earth–Moon distances of 407 000 km and 357 000 km. For the maximum angular size, the minimum distance has to be corrected for Earth's equatorial radius of 6 378 km, giving 350 600 km.
  5. ^ Lucey et al. (2006) give 107 particles cm−3 by day and 105 particles cm−3 by night. Along with equatorial surface temperatures of 390 K by day and 100 K by night, the ideal gas law yields the pressures given in the infobox (rounded to the nearest order of magnitude): 10−7 Pa by day and 10−10 Pa by night.
  6. ^ With 27% the diameter and 60% the density of Earth, the Moon has 1.23% of the mass of Earth. The moon Charon is larger relative to its primary Pluto, but Earth and the Moon are different since Pluto is considered a dwarf planet and not a planet, unlike Earth.
  7. ^ There is no strong correlation between the sizes of planets and the sizes of their satellites. Larger planets tend to have more satellites, both large and small, than smaller planets.
  8. ^ More accurately, the Moon's mean sidereal period (fixed star to fixed star) is 27.321661 days (27 d 07 h 43 min 11.5 s), and its mean tropical orbital period (from equinox to equinox) is 27.321582 days (27 d 07 h 43 min 04.7 s) (Explanatory Supplement to the Astronomical Ephemeris, 1961, at p.107).
  9. ^ More accurately, the Moon's mean synodic period (between mean solar conjunctions) is 29.530589 days (29 d 12 h 44 min 02.9 s) (Explanatory Supplement to the Astronomical Ephemeris, 1961, at p.107).
  10. ^ The Sun's apparent magnitude is −26.7, while the full moon's apparent magnitude is −12.7.
  11. ^ See graph in Sun#Life phases. At present, the diameter of the Sun is increasing at a rate of about five percent per billion years. This is very similar to the rate at which the apparent angular diameter of the Moon is decreasing as it recedes from Earth.
  12. ^ On average, the Moon covers an area of 0.21078 square degrees on the night sky.

References

  1. ^ a b c d e f g h i j k l m Wieczorek, Mark A.; Jolliff, Bradley L.; Khan, Amir; Pritchard, Matthew E.; Weiss, Benjamin P.; Williams, James G.; Hood, Lon L.; Righter, Kevin; Neal, Clive R.; Shearer, Charles K.; McCallum, I. Stewart; Tompkins, Stephanie; Hawke, B. Ray; Peterson, Chris; Gillis, Jeffrey J.; Bussey, Ben (2006). "The constitution and structure of the lunar interior". Reviews in Mineralogy and Geochemistry. 60 (1): 221–364. Bibcode:2006RvMG...60..221W. doi:10.2138/rmg.2006.60.3. S2CID 130734866.
  2. ^ a b Lang, Kenneth R. (2011). The Cambridge Guide to the Solar System (2nd ed.). Cambridge University Press. ISBN 978-1139494175. Archived from the original on January 1, 2016.
  3. ^ Morais, M. H. M.; Morbidelli, A. (2002). "The Population of Near-Earth Asteroids in Coorbital Motion with the Earth". Icarus. 160 (1): 1–9. Bibcode:2002Icar..160....1M. doi:10.1006/icar.2002.6937. hdl:10316/4391. S2CID 55214551.
  4. ^ a b c d e f g h i j k Williams, David R. (February 2, 2006). "Moon Fact Sheet". NASA/National Space Science Data Center. Archived from the original on March 23, 2010. Retrieved December 31, 2008.
  5. ^ Smith, David E.; Zuber, Maria T.; Neumann, Gregory A.; Lemoine, Frank G. (January 1, 1997). "Topography of the Moon from the Clementine lidar". Journal of Geophysical Research. 102 (E1): 1601. Bibcode:1997JGR...102.1591S. doi:10.1029/96JE02940. hdl:2060/19980018849. ISSN 0148-0227. S2CID 17475023.
  6. ^ Terry, Paul (2013). Top 10 of Everything. Octopus Publishing Group Ltd. p. 226. ISBN 978-0-600-62887-3.
  7. ^ Williams, James G.; Newhall, XX; Dickey, Jean O. (1996). "Lunar moments, tides, orientation, and coordinate frames". Planetary and Space Science. 44 (10): 1077–1080. Bibcode:1996P&SS...44.1077W. doi:10.1016/0032-0633(95)00154-9.
  8. ^ a b Hamilton, Calvin J.; Hamilton, Rosanna L., The Moon, Views of the Solar System Archived February 4, 2016, at the Wayback Machine, 1995–2011.
  9. ^ Makemson, Maud W. (1971). "Determination of selenographic positions". The Moon. 2 (3): 293–308. Bibcode:1971Moon....2..293M. doi:10.1007/BF00561882. S2CID 119603394.
  10. ^ a b Archinal, Brent A.; A'Hearn, Michael F.; Bowell, Edward G.; Conrad, Albert R.; Consolmagno, Guy J.; Courtin, Régis; Fukushima, Toshio; Hestroffer, Daniel; Hilton, James L.; Krasinsky, George A.; Neumann, Gregory A.; Oberst, Jürgen; Seidelmann, P. Kenneth; Stooke, Philip J.; Tholen, David J.; Thomas, Paul C.; Williams, Iwan P. (2010). "Report of the IAU Working Group on Cartographic Coordinates and Rotational Elements: 2009" (PDF). Celestial Mechanics and Dynamical Astronomy. 109 (2): 101–135. Bibcode:2011CeMDA.109..101A. doi:10.1007/s10569-010-9320-4. S2CID 189842666. Archived from the original (PDF) on March 4, 2016. Retrieved September 24, 2018. also available "via usgs.gov" (PDF). Archived (PDF) from the original on April 27, 2019. Retrieved September 26, 2018.
  11. ^ Matthews, Grant (2008). "Celestial body irradiance determination from an underfilled satellite radiometer: application to albedo and thermal emission measurements of the Moon using CERES". Applied Optics. 47 (27): 4981–4993. Bibcode:2008ApOpt..47.4981M. doi:10.1364/AO.47.004981. PMID 18806861.
  12. ^ a b Bugby, D. C.; Farmer, J. T.; O’Connor, B. F.; Wirzburger, M. J.; C. J. Stouffer, E. D. Abel (January 2010). Two-Phase Thermal Switching System for a Small, Extended Duration Lunar Surface Science Platform. AIP Conference Proceedings. Vol. 1208. pp. 76–83. Bibcode:2010AIPC.1208...76B. doi:10.1063/1.3326291. hdl:2060/20100009810.
  13. ^ Vasavada, A. R.; Paige, D. A.; Wood, S. E. (1999). "Near-Surface Temperatures on Mercury and the Moon and the Stability of Polar Ice Deposits". Icarus. 141 (2): 179–193. Bibcode:1999Icar..141..179V. doi:10.1006/icar.1999.6175. S2CID 37706412.
  14. ^ a b c Zhang S, Wimmer-Schweingruber RF, Yu J, Wang C, Fu Q, Zou Y, et al. (2020). "First measurements of the radiation dose on the lunar surface". Science Advances. 6 (39). Bibcode:2020SciA....6.1334Z. doi:10.1126/sciadv.aaz1334. PMC 7518862. PMID 32978156. We measured an average total absorbed dose rate in silicon of 13.2 ± 1 μGy/hour ... LND measured an average dose equivalent of 1369 μSv/day on the surface of the Moon
  15. ^ "Encyclopedia - the brightest bodies". IMCCE. Archived from the original on March 21, 2023. Retrieved June 1, 2023.
  16. ^ a b c Lucey, Paul; Korotev, Randy L.; Gillis, Jeffrey J.; Taylor, Larry A.; Lawrence, David; Campbell, Bruce A.; Elphic, Rick; Feldman, Bill; Hood, Lon L.; Hunten, Donald; Mendillo, Michael; Noble, Sarah; Papike, James J.; Reedy, Robert C.; Lawson, Stefanie; Prettyman, Tom; Gasnault, Olivier; Maurice, Sylvestre (2006). "Understanding the lunar surface and space-Moon interactions". Reviews in Mineralogy and Geochemistry. 60 (1): 83–219. Bibcode:2006RvMG...60...83L. doi:10.2138/rmg.2006.60.2.
  17. ^ a b Metzger, Philip; Grundy, Will; Sykes, Mark; Stern, Alan; Bell, James; Detelich, Charlene; Runyon, Kirby; Summers, Michael (2021). "Moons are planets: Scientific usefulness versus cultural teleology in the taxonomy of planetary science". Icarus. 374: 114768. arXiv:2110.15285. Bibcode:2022Icar..37414768M. doi:10.1016/j.icarus.2021.114768. S2CID 240071005.
  18. ^ "Is the 'full moon' merely a fallacy?". NBC News. February 28, 2004. Archived from the original on June 1, 2023. Retrieved May 30, 2023.
  19. ^ "Naming Astronomical Objects: Spelling of Names". International Astronomical Union. Archived from the original on December 16, 2008. Retrieved April 6, 2020.
  20. ^ "Gazetteer of Planetary Nomenclature: Planetary Nomenclature FAQ". USGS Astrogeology Research Program. Archived from the original on May 27, 2010. Retrieved April 6, 2020.
  21. ^ Orel, Vladimir (2003). A Handbook of Germanic Etymology. Brill. Archived from the original on June 17, 2020. Retrieved March 5, 2020.
  22. ^ López-Menchero, Fernando (May 22, 2020). "Late Proto-Indo-European Etymological Lexicon". Archived from the original on May 22, 2020. Retrieved July 30, 2022.
  23. ^ Barnhart, Robert K. (1995). The Barnhart Concise Dictionary of Etymology. HarperCollins. p. 487. ISBN 978-0-06-270084-1.
  24. ^ E.g.: Hall III, James A. (2016). Moons of the Solar System. Springer International. ISBN 978-3-319-20636-3.
  25. ^ "Luna". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
  26. ^ "Cynthia". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
  27. ^ "selenian". Merriam-Webster.com Dictionary. Merriam-Webster.
  28. ^ "selenian". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
  29. ^ "selenic". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
  30. ^ "selenic". Merriam-Webster.com Dictionary. Merriam-Webster.
  31. ^ "Oxford English Dictionary: lunar, a. and n." Oxford English Dictionary: Second Edition 1989. Oxford University Press. Archived from the original on August 19, 2020. Retrieved March 23, 2010.
  32. ^ σελήνη. Liddell, Henry George; Scott, Robert; A Greek–English Lexicon at the Perseus Project.
  33. ^ Pannen, Imke (2010). When the Bad Bleeds: Mantic Elements in English Renaissance Revenge Tragedy. V&R unipress GmbH. pp. 96–. ISBN 978-3-89971-640-5. Archived from the original on September 4, 2016.
  34. ^ "The two-faced Moon". The Planetary Society. March 14, 2022. Archived from the original on April 28, 2023. Retrieved April 28, 2023.
  35. ^ "Exploring the Planets: Chapter 4. The Moon". explanet.info. Archived from the original on April 28, 2023. Retrieved April 28, 2023.
  36. ^ Thiemens, Maxwell M.; Sprung, Peter; Fonseca, Raúl O. C.; Leitzke, Felipe P.; Münker, Carsten (July 2019). "Early Moon formation inferred from hafnium-tungsten systematics". Nature Geoscience. 12 (9): 696–700. Bibcode:2019NatGe..12..696T. doi:10.1038/s41561-019-0398-3. S2CID 198997377.
  37. ^ "The Moon is older than scientists thought". Universe Today. Archived from the original on August 3, 2019. Retrieved August 3, 2019.
  38. ^ Barboni, M.; Boehnke, P.; Keller, C.B.; Kohl, I.E.; Schoene, B.; Young, E.D.; McKeegan, K.D. (2017). "Early formation of the Moon 4.51 billion years ago". Science Advances. 3 (1): e1602365. Bibcode:2017SciA....3E2365B. doi:10.1126/sciadv.1602365. PMC 5226643. PMID 28097222.
  39. ^ Binder, A. B. (1974). "On the origin of the Moon by rotational fission". The Moon. 11 (2): 53–76. Bibcode:1974Moon...11...53B. doi:10.1007/BF01877794. S2CID 122622374.
  40. ^ a b c Stroud, Rick (2009). The Book of the Moon. Walken and Company. pp. 24–27. ISBN 978-0-8027-1734-4. Archived from the original on June 17, 2020. Retrieved November 11, 2019.
  41. ^ Mitler, H. E. (1975). "Formation of an iron-poor moon by partial capture, or: Yet another exotic theory of lunar origin". Icarus. 24 (2): 256–268. Bibcode:1975Icar...24..256M. doi:10.1016/0019-1035(75)90102-5.
  42. ^ Stevenson, D.J. (1987). "Origin of the moon–The collision hypothesis". Annual Review of Earth and Planetary Sciences. 15 (1): 271–315. Bibcode:1987AREPS..15..271S. doi:10.1146/annurev.ea.15.050187.001415. S2CID 53516498.
  43. ^ Taylor, G. Jeffrey (December 31, 1998). "Origin of the Earth and Moon". Planetary Science Research Discoveries. Hawai'i Institute of Geophysics and Planetology. Archived from the original on June 10, 2010. Retrieved April 7, 2010.
  44. ^ "Asteroids Bear Scars of Moon's Violent Formation". April 16, 2015. Archived from the original on October 8, 2016.
  45. ^ van Putten, Maurice H. P. M. (July 2017). "Scaling in global tidal dissipation of the Earth-Moon system". New Astronomy. 54: 115–121. arXiv:1609.07474. Bibcode:2017NewA...54..115V. doi:10.1016/j.newast.2017.01.012. S2CID 119285032.
  46. ^ Canup, R.; Asphaug, E. (2001). "Origin of the Moon in a giant impact near the end of Earth's formation". Nature. 412 (6848): 708–712. Bibcode:2001Natur.412..708C. doi:10.1038/35089010. PMID 11507633. S2CID 4413525.
  47. ^ "Earth-Asteroid Collision Formed Moon Later Than Thought". National Geographic. October 28, 2010. Archived from the original on April 18, 2009. Retrieved May 7, 2012.
  48. ^ Kleine, Thorsten (2008). "2008 Pellas-Ryder Award for Mathieu Touboul" (PDF). Meteoritics and Planetary Science. 43 (S7): A11–A12. Bibcode:2008M&PS...43...11K. doi:10.1111/j.1945-5100.2008.tb00709.x. S2CID 128609987. Archived from the original (PDF) on July 27, 2018. Retrieved April 8, 2020.
  49. ^ Touboul, M.; Kleine, T.; Bourdon, B.; Palme, H.; Wieler, R. (2007). "Late formation and prolonged differentiation of the Moon inferred from W isotopes in lunar metals". Nature. 450 (7173): 1206–1209. Bibcode:2007Natur.450.1206T. doi:10.1038/nature06428. PMID 18097403. S2CID 4416259.
  50. ^ "Flying Oceans of Magma Help Demystify the Moon's Creation". National Geographic. April 8, 2015. Archived from the original on April 9, 2015.
  51. ^ Pahlevan, Kaveh; Stevenson, David J. (2007). "Equilibration in the aftermath of the lunar-forming giant impact". Earth and Planetary Science Letters. 262 (3–4): 438–449. arXiv:1012.5323. Bibcode:2007E&PSL.262..438P. doi:10.1016/j.epsl.2007.07.055. S2CID 53064179.
  52. ^ Nield, Ted (2009). "Moonwalk (summary of meeting at Meteoritical Society's 72nd Annual Meeting, Nancy, France)". Geoscientist. Vol. 19. p. 8. Archived from the original on September 27, 2012.
  53. ^ a b Warren, P. H. (1985). "The magma ocean concept and lunar evolution". Annual Review of Earth and Planetary Sciences. 13 (1): 201–240. Bibcode:1985AREPS..13..201W. doi:10.1146/annurev.ea.13.050185.001221.
  54. ^ Tonks, W. Brian; Melosh, H. Jay (1993). "Magma ocean formation due to giant impacts". Journal of Geophysical Research. 98 (E3): 5319–5333. Bibcode:1993JGR....98.5319T. doi:10.1029/92JE02726.
  55. ^ Daniel Clery (October 11, 2013). "Impact Theory Gets Whacked". Science. 342 (6155): 183–185. Bibcode:2013Sci...342..183C. doi:10.1126/science.342.6155.183. PMID 24115419.
  56. ^ Akram, W.; Schönbächler, M. (September 1, 2016). "Zirconium isotope constraints on the composition of Theia and current Moon-forming theories". Earth and Planetary Science Letters. 449: 302–310. Bibcode:2016E&PSL.449..302A. doi:10.1016/j.epsl.2016.05.022. hdl:20.500.11850/117905.
  57. ^ Kegerreis, J.A.; et al. (October 4, 2022). "Immediate Origin of the Moon as a Post-impact Satellite". The Astrophysical Journal Letters. 937 (L40): L40. arXiv:2210.01814. Bibcode:2022ApJ...937L..40K. doi:10.3847/2041-8213/ac8d96. S2CID 249267497.
  58. ^ Chang, Kenneth (November 1, 2023). "A 'Big Whack' Formed the Moon and Left Traces Deep in Earth, a Study Suggests - Two enormous blobs deep inside Earth could be remnants of the birth of the moon". The New York Times. Archived from the original on November 1, 2023. Retrieved November 2, 2023.
  59. ^ Yuan, Qian; et al. (November 1, 2023). "Moon-forming impactor as a source of Earth's basal mantle anomalies". Nature. 623 (7985): 95–99. Bibcode:2023Natur.623...95Y. doi:10.1038/s41586-023-06589-1. PMID 37914947. S2CID 264869152. Archived from the original on November 2, 2023. Retrieved November 2, 2023.
  60. ^ a b "Earth-Moon Dynamics". Lunar and Planetary Institute. Archived from the original on September 7, 2015. Retrieved September 2, 2022.
  61. ^ Wisdom, Jack; Tian, ZhenLiang (August 2015). "Early evolution of the Earth-Moon system with a fast-spinning Earth". Icarus. 256: 138–146. Bibcode:2015Icar..256..138W. doi:10.1016/j.icarus.2015.02.025.
  62. ^ a b John, Tara (October 9, 2017). "NASA: The Moon Once Had an Atmosphere That Faded Away". Time. Archived from the original on May 14, 2023. Retrieved May 16, 2023.
  63. ^ a b c Hiesinger, H.; Head, J. W.; Wolf, U.; Jaumann, R.; Neukum, G. (2003). "Ages and stratigraphy of mare basalts in Oceanus Procellarum, Mare Numbium, Mare Cognitum, and Mare Insularum". Journal of Geophysical Research. 108 (E7): 1029. Bibcode:2003JGRE..108.5065H. doi:10.1029/2002JE001985. S2CID 9570915.
  64. ^ a b c Papike, J.; Ryder, G.; Shearer, C. (1998). "Lunar Samples". Reviews in Mineralogy and Geochemistry. 36: 5.1–5.234.
  65. ^ "Lunar Far Side Highlands". ESA Science & Technology. July 14, 2006. Archived from the original on September 2, 2022. Retrieved September 2, 2022.
  66. ^ Garrick-Bethell, Ian; Perera, Viranga; Nimmo, Francis; Zuber, Maria T. (2014). "The tidal-rotational shape of the Moon and evidence for polar wander" (PDF). Nature. 512 (7513): 181–184. Bibcode:2014Natur.512..181G. doi:10.1038/nature13639. PMID 25079322. S2CID 4452886. Archived (PDF) from the original on August 4, 2020. Retrieved April 12, 2020.
  67. ^ "Space Topics: Pluto and Charon". The Planetary Society. Archived from the original on February 18, 2012. Retrieved April 6, 2010.
  68. ^ Horner, Jonti (July 18, 2019). "How big is the Moon?". Archived from the original on November 7, 2020. Retrieved November 15, 2020.
  69. ^ Dyches, Preston (July 28, 2021). "Five Things to Know about the Moon – NASA Solar System Exploration". NASA Solar System Exploration. Archived from the original on July 18, 2023. Retrieved September 24, 2023.
  70. ^ Parks, Jake (September 7, 2023). "Everything you need to know about the Moon". Astronomy Magazine. Retrieved September 9, 2024.
  71. ^ "Global Island Explorer". rmgsc.cr.usgs.gov. Retrieved September 9, 2024.
  72. ^ a b c d e f g h Spudis, P. D. (2004). "Moon". World Book Online Reference Center, NASA. Archived from the original on July 3, 2013. Retrieved April 12, 2007.
  73. ^ Runcorn, Stanley Keith (March 31, 1977). "Interpretation of lunar potential fields". Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences. 285 (1327): 507–516. Bibcode:1977RSPTA.285..507R. doi:10.1098/rsta.1977.0094. S2CID 124703189.
  74. ^ Brown, D.; Anderson, J. (January 6, 2011). "NASA Research Team Reveals Moon Has Earth-Like Core". NASA. Archived from the original on January 11, 2012.
  75. ^ Weber, R.C.; Lin, P.-Y.; Garnero, E.J.; Williams, Q.; Lognonne, P. (January 21, 2011). "Seismic Detection of the Lunar Core" (PDF). Science. 331 (6015): 309–312. Bibcode:2011Sci...331..309W. doi:10.1126/science.1199375. PMID 21212323. S2CID 206530647. Archived from the original (PDF) on October 15, 2015. Retrieved April 10, 2017.
  76. ^ Nemchin, A.; Timms, N.; Pidgeon, R.; Geisler, T.; Reddy, S.; Meyer, C. (2009). "Timing of crystallization of the lunar magma ocean constrained by the oldest zircon". Nature Geoscience. 2 (2): 133–136. Bibcode:2009NatGe...2..133N. doi:10.1038/ngeo417. hdl:20.500.11937/44375.
  77. ^ a b Shearer, Charles K.; Hess, Paul C.; Wieczorek, Mark A.; Pritchard, Matt E.; Parmentier, E. Mark; Borg, Lars E.; Longhi, John; Elkins-Tanton, Linda T.; Neal, Clive R.; Antonenko, Irene; Canup, Robin M.; Halliday, Alex N.; Grove, Tim L.; Hager, Bradford H.; Lee, D.-C.; Wiechert, Uwe (2006). "Thermal and magmatic evolution of the Moon". Reviews in Mineralogy and Geochemistry. 60 (1): 365–518. Bibcode:2006RvMG...60..365S. doi:10.2138/rmg.2006.60.4. S2CID 129184748.
  78. ^ Schubert, J. (2004). "Interior composition, structure, and dynamics of the Galilean satellites.". In F. Bagenal; et al. (eds.). Jupiter: The Planet, Satellites, and Magnetosphere. Cambridge University Press. pp. 281–306. ISBN 978-0-521-81808-7.
  79. ^ Williams, J.G.; Turyshev, S.G.; Boggs, D.H.; Ratcliff, J.T. (2006). "Lunar laser ranging science: Gravitational physics and lunar interior and geodesy". Advances in Space Research. 37 (1): 67–71. arXiv:gr-qc/0412049. Bibcode:2006AdSpR..37...67W. doi:10.1016/j.asr.2005.05.013. S2CID 14801321.
  80. ^ Evans, Alexander J.; Tikoo, Sonia M.; Jeffrey C., Andrews-Hanna (January 2018). "The Case Against an Early Lunar Dynamo Powered by Core Convection". Geophysical Research Letters. 45 (1): 98–107. Bibcode:2018GeoRL..45...98E. doi:10.1002/2017GL075441.
  81. ^ Kluger, Jeffrey (October 12, 2018). "How Neil Armstrong's Moon Spacesuit Was Preserved for Centuries to Come". Time. Archived from the original on December 3, 2023. Retrieved November 29, 2023.
  82. ^ "How Do You Pick Up Something on the Moon?". WIRED. December 9, 2013. Archived from the original on December 3, 2023. Retrieved November 29, 2023.
  83. ^ Muller, P.; Sjogren, W. (1968). "Mascons: lunar mass concentrations". Science. 161 (3842): 680–684. Bibcode:1968Sci...161..680M. doi:10.1126/science.161.3842.680. PMID 17801458. S2CID 40110502.
  84. ^ Richard A. Kerr (April 12, 2013). "The Mystery of Our Moon's Gravitational Bumps Solved?". Science. 340 (6129): 138–139. doi:10.1126/science.340.6129.138-a. PMID 23580504.
  85. ^ Konopliv, A.; Asmar, S.; Carranza, E.; Sjogren, W.; Yuan, D. (2001). "Recent gravity models as a result of the Lunar Prospector mission" (PDF). Icarus. 50 (1): 1–18. Bibcode:2001Icar..150....1K. CiteSeerX 10.1.1.18.1930. doi:10.1006/icar.2000.6573. Archived from the original (PDF) on November 13, 2004.
  86. ^ a b c Mighani, S.; Wang, H.; Shuster, D.L.; Borlina, C.S.; Nichols, C.I.O.; Weiss, B.P. (2020). "The end of the lunar dynamo". Science Advances. 6 (1): eaax0883. Bibcode:2020SciA....6..883M. doi:10.1126/sciadv.aax0883. PMC 6938704. PMID 31911941.
  87. ^ Garrick-Bethell, Ian; Weiss, iBenjamin P.; Shuster, David L.; Buz, Jennifer (2009). "Early Lunar Magnetism". Science. 323 (5912): 356–359. Bibcode:2009Sci...323..356G. doi:10.1126/science.1166804. PMID 19150839. S2CID 23227936.
  88. ^ "Magnetometer / Electron Reflectometer Results". Lunar Prospector (NASA). 2001. Archived from the original on May 27, 2010. Retrieved March 17, 2010.
  89. ^ Hood, L.L.; Huang, Z. (1991). "Formation of magnetic anomalies antipodal to lunar impact basins: Two-dimensional model calculations". Journal of Geophysical Research. 96 (B6): 9837–9846. Bibcode:1991JGR....96.9837H. doi:10.1029/91JB00308.
  90. ^ "Lunar horizon glow from Surveyor 7". The Planetary Society. May 6, 2016. Archived from the original on August 8, 2022. Retrieved August 8, 2022.
  91. ^ "NASA Mission To Study Mysterious Lunar Twilight Rays". Science Mission Directorate. September 3, 2013. Archived from the original on July 3, 2022. Retrieved August 8, 2022.
  92. ^ Colwell, Joshua E.; Robertson, Scott R.; Horányi, Mihály; Wang, Xu; Poppe, Andrew; Wheeler, Patrick (January 1, 2009). "Lunar Dust Levitation". Journal of Aerospace Engineering. 22 (1): 2–9. doi:10.1061/(ASCE)0893-1321(2009)22:1(2). Archived from the original on August 8, 2022. Retrieved August 8, 2022.
  93. ^ Deborah Byrd (April 24, 2014). "The zodiacal light, seen from the moon". EarthSky. Archived from the original on August 8, 2022. Retrieved August 8, 2022.
  94. ^ Globus, Ruth (1977). "Chapter 5, Appendix J: Impact Upon Lunar Atmosphere". In Richard D. Johnson & Charles Holbrow (ed.). Space Settlements: A Design Study. NASA. Archived from the original on May 31, 2010. Retrieved March 17, 2010.
  95. ^ Crotts, Arlin P.S. (2008). "Lunar Outgassing, Transient Phenomena and The Return to The Moon, I: Existing Data" (PDF). The Astrophysical Journal. 687 (1): 692–705. arXiv:0706.3949. Bibcode:2008ApJ...687..692C. doi:10.1086/591634. S2CID 16821394. Archived from the original (PDF) on February 20, 2009. Retrieved September 29, 2009.
  96. ^ Steigerwald, William (August 17, 2015). "NASA's LADEE Spacecraft Finds Neon in Lunar Atmosphere". NASA. Archived from the original on August 19, 2015. Retrieved August 18, 2015.
  97. ^ a b c Stern, S.A. (1999). "The Lunar atmosphere: History, status, current problems, and context". Reviews of Geophysics. 37 (4): 453–491. Bibcode:1999RvGeo..37..453S. CiteSeerX 10.1.1.21.9994. doi:10.1029/1999RG900005. S2CID 10406165.
  98. ^ Lawson, S.; Feldman, W.; Lawrence, D.; Moore, K.; Elphic, R.; Belian, R. (2005). "Recent outgassing from the lunar surface: the Lunar Prospector alpha particle spectrometer". Journal of Geophysical Research. 110 (E9): 1029. Bibcode:2005JGRE..110.9009L. doi:10.1029/2005JE002433.
  99. ^ R. Sridharan; S.M. Ahmed; Tirtha Pratim Dasa; P. Sreelathaa; P. Pradeepkumara; Neha Naika; Gogulapati Supriya (2010). "'Direct' evidence for water (H2O) in the sunlit lunar ambience from CHACE on MIP of Chandrayaan I". Planetary and Space Science. 58 (6): 947–950. Bibcode:2010P&SS...58..947S. doi:10.1016/j.pss.2010.02.013.
  100. ^ Drake, Nadia (June 17, 2015). "Lopsided Cloud of Dust Discovered Around the Moon". National Geographic News. Archived from the original on June 19, 2015. Retrieved June 20, 2015.
  101. ^ Horányi, M.; Szalay, J.R.; Kempf, S.; Schmidt, J.; Grün, E.; Srama, R.; Sternovsky, Z. (June 18, 2015). "A permanent, asymmetric dust cloud around the Moon". Nature. 522 (7556): 324–326. Bibcode:2015Natur.522..324H. doi:10.1038/nature14479. PMID 26085272. S2CID 4453018.
  102. ^ James, John; Kahn-Mayberry, Noreen (January 2009). "Risk of Adverse Health Effects from Lunar Dust Exposure" (PDF). Archived (PDF) from the original on December 4, 2021. Retrieved December 8, 2022.
  103. ^ "Radioactive Moon". Science Mission Directorate. September 8, 2005. Archived from the original on November 2, 2019. Retrieved July 28, 2022.
  104. ^ "We Finally Know How Much Radiation There Is on The Moon, And It's Not Great News". ScienceAlert. September 26, 2020. Archived from the original on July 28, 2022. Retrieved July 28, 2022.
  105. ^ Paris, Antonio; Davies, Evan; Tognetti, Laurence; Zahniser, Carly (April 27, 2020). "Prospective Lava Tubes at Hellas Planitia". arXiv:2004.13156v1 [astro-ph.EP].
  106. ^ Wall, Mike (December 9, 2013). "Radiation on Mars 'Manageable' for Manned Mission, Curiosity Rover Reveals". Space.com. Archived from the original on December 15, 2020. Retrieved August 7, 2022.
  107. ^ Rambaux, N.; Williams, J. G. (2011). "The Moon's physical librations and determination of their free modes". Celestial Mechanics and Dynamical Astronomy. 109 (1): 85–100. Bibcode:2011CeMDA.109...85R. doi:10.1007/s10569-010-9314-2. S2CID 45209988. Archived from the original on July 30, 2022. Retrieved July 30, 2022.
  108. ^ Rocheleau, Jake (May 21, 2012). "Temperature on the Moon – Surface Temperature of the Moon". PlanetFacts.org. Archived from the original on May 27, 2015.
  109. ^ a b Amos, Jonathan (December 16, 2009). "'Coldest place' found on the Moon". BBC News. Archived from the original on August 11, 2017. Retrieved March 20, 2010.
  110. ^ a b Martel, L. M. V. (June 4, 2003). "The Moon's Dark, Icy Poles". Planetary Science Research Discoveries: 73. Bibcode:2003psrd.reptE..73M. Archived from the original on March 1, 2012. Retrieved April 12, 2007.
  111. ^ "Diviner News". UCLA. September 17, 2009. Archived from the original on March 7, 2010. Retrieved March 17, 2010.
  112. ^ "The Smell of Moondust". NASA. January 30, 2006. Archived from the original on March 8, 2010. Retrieved March 15, 2010.
  113. ^ Heiken, G. (1991). Vaniman, D.; French, B. (eds.). Lunar Sourcebook, a user's guide to the Moon. New York: Cambridge University Press. p. 286. ISBN 978-0-521-33444-0. Archived from the original on June 17, 2020. Retrieved December 17, 2019.
  114. ^ Rasmussen, K.L.; Warren, P.H. (1985). "Megaregolith thickness, heat flow, and the bulk composition of the Moon". Nature. 313 (5998): 121–124. Bibcode:1985Natur.313..121R. doi:10.1038/313121a0. S2CID 4245137.
  115. ^ Schuerger, Andrew C.; Moores, John E.; Smith, David J.; Reitz, Günther (June 2019). "A Lunar Microbial Survival Model for Predicting the Forward Contamination of the Moon". Astrobiology. 19 (6): 730–756. Bibcode:2019AsBio..19..730S. doi:10.1089/ast.2018.1952. PMID 30810338. S2CID 73491587.
  116. ^ Spudis, Paul D.; Cook, A.; Robinson, M.; Bussey, B.; Fessler, B. (January 1998). "Topography of the South Polar Region from Clementine Stereo Imaging". Workshop on New Views of the Moon: Integrated Remotely Sensed, Geophysical, and Sample Datasets: 69. Bibcode:1998nvmi.conf...69S.
  117. ^ a b c Spudis, Paul D.; Reisse, Robert A.; Gillis, Jeffrey J. (1994). "Ancient Multiring Basins on the Moon Revealed by Clementine Laser Altimetry". Science. 266 (5192): 1848–1851. Bibcode:1994Sci...266.1848S. doi:10.1126/science.266.5192.1848. PMID 17737079. S2CID 41861312.
  118. ^ Pieters, C. M.; Tompkins, S.; Head, J. W.; Hess, P. C. (1997). "Mineralogy of the Mafic Anomaly in the South Pole-Aitken Basin: Implications for excavation of the lunar mantle". Geophysical Research Letters. 24 (15): 1903–1906. Bibcode:1997GeoRL..24.1903P. doi:10.1029/97GL01718. hdl:2060/19980018038. S2CID 128767066.
  119. ^ Taylor, G. J. (July 17, 1998). "The Biggest Hole in the Solar System". Planetary Science Research Discoveries: 20. Bibcode:1998psrd.reptE..20T. Archived from the original on August 20, 2007. Retrieved April 12, 2007.
  120. ^ Schultz, P.H. (March 1997). "Forming the south-pole Aitken basin – The extreme games". Conference Paper, 28th Annual Lunar and Planetary Science Conference. 28: 1259. Bibcode:1997LPI....28.1259S.
  121. ^ "NASA's LRO Reveals 'Incredible Shrinking Moon'". NASA. August 19, 2010. Archived from the original on August 21, 2010.
  122. ^ Watters, Thomas R.; Weber, Renee C.; Collins, Geoffrey C.; Howley, Ian J.; Schmerr, Nicholas C.; Johnson, Catherine L. (June 2019). "Shallow seismic activity and young thrust faults on the Moon". Nature Geoscience. 12 (6) (published May 13, 2019): 411–417. Bibcode:2019NatGe..12..411W. doi:10.1038/s41561-019-0362-2. ISSN 1752-0894. S2CID 182137223.
  123. ^ "Cave on the Moon: What this discovery means for space exploration". The Indian Express. July 18, 2024. Retrieved July 19, 2024.
  124. ^ Wlasuk, Peter (2000). Observing the Moon. Springer. p. 19. ISBN 978-1-85233-193-1.
  125. ^ Norman, M. (April 21, 2004). "The Oldest Moon Rocks". Planetary Science Research Discoveries. Hawai'i Institute of Geophysics and Planetology. Archived from the original on April 18, 2007. Retrieved April 12, 2007.
  126. ^ Friedman, R.C.; Blewett, D. T.; Taylor, G.J.; Lucey, P. G. (1996). "FeO and TiO2 Variations in Mare Imbrium". Lunar and Planetary Science. 27: 383. Bibcode:1996LPI....27..383F.
  127. ^ Izquierdo, Kristel; Sori, M. M.; Checketts, B.; Hampton, I.; Johnson, B.C.; Soderblom, J.M. (2024). "Global Distribution and Volume of Cryptomare and Visible Mare on the Moon From Gravity and Dark Halo Craters". AGU. 129 (2). Bibcode:2024JGRE..12907867I. doi:10.1029/2023JE007867.
  128. ^ Spudis, Paul (2016). "Mapping Melts on the Moon". Smithsonian Air and Space Magazine.
  129. ^ Wilson, Lionel; Head, James W. (2003). "Lunar Gruithuisen and Mairan domes: Rheology and mode of emplacement". Journal of Geophysical Research. 108 (E2): 5012. Bibcode:2003JGRE..108.5012W. CiteSeerX 10.1.1.654.9619. doi:10.1029/2002JE001909. S2CID 14917901. Archived from the original on March 12, 2007. Retrieved April 12, 2007.
  130. ^ Gillis, J. J.; Spudis, P. D. (1996). "The Composition and Geologic Setting of Lunar Far Side Maria". Lunar and Planetary Science. 27: 413. Bibcode:1996LPI....27..413G.
  131. ^ Lawrence, D. J.; Feldman, W. C.; Barraclough, B. L.; Binder, A. B.; Elphic, R. C.; Maurice, S.; Thomsen, D. R. (August 11, 1998). "Global Elemental Maps of the Moon: The Lunar Prospector Gamma-Ray Spectrometer". Science. 281 (5382): 1484–1489. Bibcode:1998Sci...281.1484L. doi:10.1126/science.281.5382.1484. PMID 9727970.
  132. ^ Taylor, G. J. (August 31, 2000). "A New Moon for the Twenty-First Century". Planetary Science Research Discoveries: 41. Bibcode:2000psrd.reptE..41T. Archived from the original on March 1, 2012. Retrieved April 12, 2007.
  133. ^ a b Phil Berardelli (November 9, 2006). "Long Live the Moon!". Science. Archived from the original on October 18, 2014. Retrieved October 14, 2014.
  134. ^ Jason Major (October 14, 2014). "Volcanoes Erupted 'Recently' on the Moon". Discovery News. Archived from the original on October 16, 2014.
  135. ^ "NASA Mission Finds Widespread Evidence of Young Lunar Volcanism". NASA. October 12, 2014. Archived from the original on January 3, 2015.
  136. ^ Eric Hand (October 12, 2014). "Recent volcanic eruptions on the moon". Science. Archived from the original on October 14, 2014.
  137. ^ Braden, S.E.; Stopar, J.D.; Robinson, M.S.; Lawrence, S.J.; van der Bogert, C.H.; Hiesinger, H. (2014). "Evidence for basaltic volcanism on the Moon within the past 100 million years". Nature Geoscience. 7 (11): 787–791. Bibcode:2014NatGe...7..787B. doi:10.1038/ngeo2252.
  138. ^ Srivastava, N.; Gupta, R.P. (2013). "Young viscous flows in the Lowell crater of Orientale basin, Moon: Impact melts or volcanic eruptions?". Planetary and Space Science. 87: 37–45. Bibcode:2013P&SS...87...37S. doi:10.1016/j.pss.2013.09.001.
  139. ^ Gupta, R.P.; Srivastava, N.; Tiwari, R.K. (2014). "Evidences of relatively new volcanic flows on the Moon". Current Science. 107 (3): 454–460. JSTOR 24103498.
  140. ^ Whitten, Jennifer; Head, James W.; Staid, Matthew; Pieters, Carle M.; Mustard, John; Clark, Roger; Nettles, Jeff; Klima, Rachel L.; Taylor, Larry (2011). "Lunar mare deposits associated with the Orientale impact basin: New insights into mineralogy, history, mode of emplacement, and relation to Orientale Basin evolution from Moon Mineralogy Mapper (M3) data from Chandrayaan-1". Journal of Geophysical Research. 116: E00G09. Bibcode:2011JGRE..116.0G09W. doi:10.1029/2010JE003736. S2CID 7234547.
  141. ^ Cho, Y.; et al. (2012). "Young mare volcanism in the Orientale region contemporary with the Procellarum KREEP Terrane (PKT) volcanism peak period 2 b.y. ago". Geophysical Research Letters. 39 (11): L11203. Bibcode:2012GeoRL..3911203C. doi:10.1029/2012GL051838. S2CID 134074700.
  142. ^ Munsell, K. (December 4, 2006). "Majestic Mountains". Solar System Exploration. NASA. Archived from the original on September 17, 2008. Retrieved April 12, 2007.
  143. ^ Richard Lovett (2011). "Early Earth may have had two moons : Nature News". Nature. doi:10.1038/news.2011.456. Archived from the original on November 3, 2012. Retrieved November 1, 2012.
  144. ^ "Was our two-faced moon in a small collision?". Theconversation.edu.au. Archived from the original on January 30, 2013. Retrieved November 1, 2012.
  145. ^ Quillen, Alice C.; Martini, Larkin; Nakajima, Miki (September 2019). "Near/far side asymmetry in the tidally heated Moon". Icarus. 329: 182–196. arXiv:1810.10676. Bibcode:2019Icar..329..182Q. doi:10.1016/j.icarus.2019.04.010. PMC 7489467. PMID 32934397.
  146. ^ Melosh, H. J. (1989). Impact cratering: A geologic process. Oxford University Press. ISBN 978-0-19-504284-9.
  147. ^ "Moon Facts". SMART-1. European Space Agency. 2010. Archived from the original on March 17, 2012. Retrieved May 12, 2010.
  148. ^ Impact Cratering Notes (LPI)
  149. ^ Herrick, R.R.; Forsberg-Taylor, N. K. (2003). "The shape and appearance of craters formed by oblique impact on the Moon and Venus". Meteoritics & Planetary Science. 38 (11): 1551–1578. Bibcode:2003M&PS...38.1551H. doi:10.1111/j.1945-5100.2003.tb00001.x.
  150. ^ a b Wilhelms, Don (1987). "Relative Ages" (PDF). Geologic History of the Moon. U.S. Geological Survey. Archived from the original (PDF) on June 11, 2010. Retrieved April 4, 2010.
  151. ^ Xiao, Z.; Strom, R.G. (2012). "Problems determining relative and absolute ages using the small crater population" (PDF). Icarus. 220 (1): 254–267. Bibcode:2012Icar..220..254X. doi:10.1016/j.icarus.2012.05.012.
  152. ^ Hartmann, William K.; Quantin, Cathy; Mangold, Nicolas (2007). "Possible long-term decline in impact rates: 2. Lunar impact-melt data regarding impact history". Icarus. 186 (1): 11–23. Bibcode:2007Icar..186...11H. doi:10.1016/j.icarus.2006.09.009.
  153. ^ Boyle, Rebecca. "The moon has hundreds more craters than we thought". Archived from the original on October 13, 2016.
  154. ^ Speyerer, Emerson J.; Povilaitis, Reinhold Z.; Robinson, Mark S.; Thomas, Peter C.; Wagner, Robert V. (October 13, 2016). "Quantifying crater production and regolith overturn on the Moon with temporal imaging". Nature. 538 (7624): 215–218. Bibcode:2016Natur.538..215S. doi:10.1038/nature19829. PMID 27734864. S2CID 4443574.
  155. ^ "Earth's Moon Hit by Surprising Number of Meteoroids". NASA. October 13, 2016. Archived from the original on July 2, 2022. Retrieved May 21, 2021.
  156. ^ Chrbolková, Kateřina; Kohout, Tomáš; Ďurech, Josef (November 2019). "Reflectance spectra of seven lunar swirls examined by statistical methods: A space weathering study". Icarus. 333: 516–527. Bibcode:2019Icar..333..516C. doi:10.1016/j.icarus.2019.05.024.
  157. ^ Margot, J. L.; Campbell, D. B.; Jurgens, R. F.; Slade, M. A. (June 4, 1999). "Topography of the Lunar Poles from Radar Interferometry: A Survey of Cold Trap Locations" (PDF). Science. 284 (5420): 1658–1660. Bibcode:1999Sci...284.1658M. CiteSeerX 10.1.1.485.312. doi:10.1126/science.284.5420.1658. PMID 10356393. Archived (PDF) from the original on August 11, 2017. Retrieved October 25, 2017.
  158. ^ Ward, William R. (August 1, 1975). "Past Orientation of the Lunar Spin Axis". Science. 189 (4200): 377–379. Bibcode:1975Sci...189..377W. doi:10.1126/science.189.4200.377. PMID 17840827. S2CID 21185695.
  159. ^ Seedhouse, Erik (2009). Lunar Outpost: The Challenges of Establishing a Human Settlement on the Moon. Springer-Praxis Books in Space Exploration. Germany: Springer Praxis. p. 136. ISBN 978-0-387-09746-6. Archived from the original on November 26, 2020. Retrieved August 22, 2020.
  160. ^ Coulter, Dauna (March 18, 2010). "The Multiplying Mystery of Moonwater". NASA. Archived from the original on December 13, 2012. Retrieved March 28, 2010.
  161. ^ Spudis, P. (November 6, 2006). "Ice on the Moon". The Space Review. Archived from the original on February 22, 2007. Retrieved April 12, 2007.
  162. ^ Feldman, W. C.; Maurice, S.; Binder, A. B.; Barraclough, B. L.; R.C. Elphic; D.J. Lawrence (1998). "Fluxes of Fast and Epithermal Neutrons from Lunar Prospector: Evidence for Water Ice at the Lunar Poles". Science. 281 (5382): 1496–1500. Bibcode:1998Sci...281.1496F. doi:10.1126/science.281.5382.1496. PMID 9727973. S2CID 9005608.
  163. ^ Saal, Alberto E.; Hauri, Erik H.; Cascio, Mauro L.; van Orman, James A.; Rutherford, Malcolm C.; Cooper, Reid F. (2008). "Volatile content of lunar volcanic glasses and the presence of water in the Moon's interior". Nature. 454 (7201): 192–195. Bibcode:2008Natur.454..192S. doi:10.1038/nature07047. PMID 18615079. S2CID 4394004.
  164. ^ Pieters, C. M.; Goswami, J. N.; Clark, R. N.; Annadurai, M.; Boardman, J.; Buratti, B.; Combe, J.-P.; Dyar, M. D.; Green, R.; Head, J. W.; Hibbitts, C.; Hicks, M.; Isaacson, P.; Klima, R.; Kramer, G.; Kumar, S.; Livo, E.; Lundeen, S.; Malaret, E.; McCord, T.; Mustard, J.; Nettles, J.; Petro, N.; Runyon, C.; Staid, M.; Sunshine, J.; Taylor, L.A.; Tompkins, S.; Varanasi, P. (2009). "Character and Spatial Distribution of OH/H2O on the Surface of the Moon Seen by M3 on Chandrayaan-1". Science. 326 (5952): 568–572. Bibcode:2009Sci...326..568P. doi:10.1126/science.1178658. PMID 19779151. S2CID 447133.
  165. ^ Li, Shuai; Lucey, Paul G.; Milliken, Ralph E.; Hayne, Paul O.; Fisher, Elizabeth; Williams, Jean-Pierre; Hurley, Dana M.; Elphic, Richard C. (August 2018). "Direct evidence of surface exposed water ice in the lunar polar regions". Proceedings of the National Academy of Sciences. 115 (36): 8907–8912. Bibcode:2018PNAS..115.8907L. doi:10.1073/pnas.1802345115. PMC 6130389. PMID 30126996.
  166. ^ Lakdawalla, Emily (November 13, 2009). "LCROSS Lunar Impactor Mission: "Yes, We Found Water!"". The Planetary Society. Archived from the original on January 22, 2010. Retrieved April 13, 2010.
  167. ^ Colaprete, A.; Ennico, K.; Wooden, D.; Shirley, M.; Heldmann, J.; Marshall, W.; Sollitt, L.; Asphaug, E.; Korycansky, D.; Schultz, P.; Hermalyn, B.; Galal, K.; Bart, G.D.; Goldstein, D.; Summy, D. (March 1–5, 2010). "Water and More: An Overview of LCROSS Impact Results". 41st Lunar and Planetary Science Conference. 41 (1533): 2335. Bibcode:2010LPI....41.2335C.
  168. ^ Colaprete, Anthony; Schultz, Peter; Heldmann, Jennifer; Wooden, Diane; Shirley, Mark; Ennico, Kimberly; Hermalyn, Brendan; Marshall, William; Ricco, Antonio; Elphic, Richard C.; Goldstein, David; Summy, Dustin; Bart, Gwendolyn D.; Asphaug, Erik; Korycansky, Don; Landis, David; Sollitt, Luke (October 22, 2010). "Detection of Water in the LCROSS Ejecta Plume". Science. 330 (6003): 463–468. Bibcode:2010Sci...330..463C. doi:10.1126/science.1186986. PMID 20966242. S2CID 206525375.
  169. ^ Hauri, Erik; Thomas Weinreich; Albert E. Saal; Malcolm C. Rutherford; James A. Van Orman (May 26, 2011). "High Pre-Eruptive Water Contents Preserved in Lunar Melt Inclusions". Science Express. 10 (1126): 213–215. Bibcode:2011Sci...333..213H. doi:10.1126/science.1204626. PMID 21617039. S2CID 44437587.
  170. ^ a b Rincon, Paul (August 21, 2018). "Water ice 'detected on Moon's surface'". BBC News. Archived from the original on August 21, 2018. Retrieved August 21, 2018.
  171. ^ David, Leonard. "Beyond the Shadow of a Doubt, Water Ice Exists on the Moon". Scientific American. Archived from the original on August 21, 2018. Retrieved August 21, 2018.
  172. ^ a b "Water Ice Confirmed on the Surface of the Moon for the 1st Time!". Space.com. Archived from the original on August 21, 2018. Retrieved August 21, 2018.
  173. ^ Honniball, C.I.; et al. (October 26, 2020). "Molecular water detected on the sunlit Moon by SOFIA". Nature Astronomy. 5 (2): 121–127. Bibcode:2021NatAs...5..121H. doi:10.1038/s41550-020-01222-x. S2CID 228954129. Archived from the original on October 27, 2020. Retrieved October 26, 2020.
  174. ^ Hayne, P.O.; et al. (October 26, 2020). "Micro cold traps on the Moon". Nature Astronomy. 5 (2): 169–175. arXiv:2005.05369. Bibcode:2021NatAs...5..169H. doi:10.1038/s41550-020-1198-9. S2CID 218595642. Archived from the original on October 27, 2020. Retrieved October 26, 2020.
  175. ^ Guarino, Ben; Achenbach, Joel (October 26, 2020). "Pair of studies confirm there is water on the moon – New research confirms what scientists had theorized for years — the moon is wet". The Washington Post. Archived from the original on October 26, 2020. Retrieved October 26, 2020.
  176. ^ Chang, Kenneth (October 26, 2020). "There's Water and Ice on the Moon, and in More Places Than NASA Once Thought – Future astronauts seeking water on the moon may not need to go into the most treacherous craters in its polar regions to find it". The New York Times. Archived from the original on October 26, 2020. Retrieved October 26, 2020.
  177. ^ The Aerospace Corporation (July 20, 2023). "It's International Moon Day! Let's talk about Cislunar Space". Medium. Archived from the original on November 8, 2023. Retrieved November 7, 2023.
  178. ^ Matt Williams (July 10, 2017). "How Long is a Day on the Moon?". Universe Today. Archived from the original on November 29, 2020. Retrieved December 5, 2020.
  179. ^ a b Stern, David (March 30, 2014). "Libration of the Moon". NASA. Archived from the original on May 22, 2020. Retrieved February 11, 2020.
  180. ^ Haigh, I. D.; Eliot, M.; Pattiaratchi, C. (2011). "Global influences of the 18.61 year nodal cycle and 8.85 year cycle of lunar perigee on high tidal levels" (PDF). J. Geophys. Res. 116 (C6): C06025. Bibcode:2011JGRC..116.6025H. doi:10.1029/2010JC006645. Archived (PDF) from the original on December 12, 2019. Retrieved September 24, 2019.
  181. ^ V V Belet︠s︡kiĭ (2001). Essays on the Motion of Celestial Bodies. Birkhäuser. p. 183. ISBN 978-3-7643-5866-2. Archived from the original on March 23, 2018. Retrieved August 22, 2020.
  182. ^ a b c d Touma, Jihad; Wisdom, Jack (1994). "Evolution of the Earth-Moon system". The Astronomical Journal. 108 (5): 1943–1961. Bibcode:1994AJ....108.1943T. doi:10.1086/117209.
  183. ^ Iain Todd (March 31, 2018). "Is the Moon maintaining Earth's magnetism?". BBC Sky at Night Magazine. Archived from the original on September 22, 2020. Retrieved November 16, 2020.
  184. ^ Latham, Gary; Ewing, Maurice; Dorman, James; Lammlein, David; Press, Frank; Toksőz, Naft; Sutton, George; Duennebier, Fred; Nakamura, Yosio (1972). "Moonquakes and lunar tectonism". Earth, Moon, and Planets. 4 (3–4): 373–382. Bibcode:1972Moon....4..373L. doi:10.1007/BF00562004. S2CID 120692155.
  185. ^ a b c d e Lambeck, K. (1977). "Tidal Dissipation in the Oceans: Astronomical, Geophysical and Oceanographic Consequences". Philosophical Transactions of the Royal Society A. 287 (1347): 545–594. Bibcode:1977RSPTA.287..545L. doi:10.1098/rsta.1977.0159. S2CID 122853694.
  186. ^ Le Provost, C.; Bennett, A.F.; Cartwright, D.E. (1995). "Ocean Tides for and from TOPEX/POSEIDON". Science. 267 (5198): 639–642. Bibcode:1995Sci...267..639L. doi:10.1126/science.267.5198.639. PMID 17745840. S2CID 13584636.
  187. ^ Chapront, J.; Chapront-Touzé, M.; Francou, G. (2002). "A new determination of lunar orbital parameters, precession constant and tidal acceleration from LLR measurements". Astronomy and Astrophysics. 387 (2): 700–709. Bibcode:2002A&A...387..700C. doi:10.1051/0004-6361:20020420. S2CID 55131241.
  188. ^ "Why the Moon is getting further away from Earth". BBC News. February 1, 2011. Archived from the original on September 25, 2015. Retrieved September 18, 2015.
  189. ^ Williams, James G.; Boggs, Dale H. (2016). "Secular tidal changes in lunar orbit and Earth rotation". Celestial Mechanics and Dynamical Astronomy. 126 (1): 89–129. Bibcode:2016CeMDA.126...89W. doi:10.1007/s10569-016-9702-3. ISSN 1572-9478. S2CID 124256137. Archived from the original on July 30, 2022. Retrieved July 30, 2022.
  190. ^ Ray, R. (May 15, 2001). "Ocean Tides and the Earth's Rotation". IERS Special Bureau for Tides. Archived from the original on March 27, 2010. Retrieved March 17, 2010.
  191. ^ Stephenson, F. R.; Morrison, L. V.; Hohenkerk, C. Y. (2016). "Measurement of the Earth's rotation: 720 BC to AD 2015". Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences. 472 (2196): 20160404. Bibcode:2016RSPSA.47260404S. doi:10.1098/rspa.2016.0404. PMC 5247521. PMID 28119545.
  192. ^ Morrison, L. V.; Stephenson, F. R.; Hohenkerk, C. Y.; Zawilski, M. (2021). "Addendum 2020 to 'Measurement of the Earth's rotation: 720 BC to AD 2015'". Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences. 477 (2246): 20200776. Bibcode:2021RSPSA.47700776M. doi:10.1098/rspa.2020.0776. S2CID 231938488.
  193. ^ "When Will Earth Lock to the Moon?". Universe Today. April 12, 2016. Archived from the original on May 28, 2022. Retrieved January 5, 2022.
  194. ^ Murray, C.D.; Dermott, Stanley F. (1999). Solar System Dynamics. Cambridge University Press. p. 184. ISBN 978-0-521-57295-8.
  195. ^ Dickinson, Terence (1993). From the Big Bang to Planet X. Camden East, Ontario: Camden House. pp. 79–81. ISBN 978-0-921820-71-0.
  196. ^ Powell, David (January 22, 2007). "Earth's Moon Destined to Disintegrate". Space.com. Tech Media Network. Archived from the original on September 6, 2008. Retrieved June 1, 2010.
  197. ^ "Moonlight helps plankton escape predators during Arctic winters". New Scientist. January 16, 2016. Archived from the original on January 30, 2016.
  198. ^ Howells, Kate (September 25, 2020). "Can the Moon be upside down?". The Planetary Society. Archived from the original on January 2, 2022. Retrieved January 2, 2022.
  199. ^ Spekkens, K. (October 18, 2002). "Is the Moon seen as a crescent (and not a "boat") all over the world?". Curious About Astronomy. Archived from the original on October 16, 2015. Retrieved September 28, 2015.
  200. ^ a b Tony Phillips (March 16, 2011). "Super Full Moon". NASA. Archived from the original on May 7, 2012. Retrieved March 19, 2011.
  201. ^ a b Richard K. De Atley (March 18, 2011). "Full moon tonight is as close as it gets". The Press-Enterprise. Archived from the original on March 22, 2011. Retrieved March 19, 2011.
  202. ^ Hershenson, Maurice (1989). The Moon illusion. Routledge. p. 5. ISBN 978-0-8058-0121-7.
  203. ^ Phil Plait. "Dark Side of the Moon". Bad Astronomy: Misconceptions. Archived from the original on April 12, 2010. Retrieved February 15, 2010.
  204. ^ Alexander, M.E. (1973). "The Weak Friction Approximation and Tidal Evolution in Close Binary Systems". Astrophysics and Space Science. 23 (2): 459–508. Bibcode:1973Ap&SS..23..459A. doi:10.1007/BF00645172. S2CID 122918899.
  205. ^ "Moon used to spin 'on different axis'". BBC News. March 23, 2016. Archived from the original on March 23, 2016. Retrieved March 23, 2016.
  206. ^ "Supermoon November 2016". Space.com. November 13, 2016. Archived from the original on November 14, 2016. Retrieved November 14, 2016.
  207. ^ "'Super moon' to reach closest point for almost 20 years". The Guardian. March 19, 2011. Archived from the original on December 25, 2013. Retrieved March 19, 2011.
  208. ^ Taylor, G. J. (November 8, 2006). "Recent Gas Escape from the Moon". Planetary Science Research Discoveries: 110. Bibcode:2006psrd.reptE.110T. Archived from the original on March 4, 2007. Retrieved April 4, 2007.
  209. ^ Schultz, P. H.; Staid, M. I.; Pieters, C. M. (2006). "Lunar activity from recent gas release". Nature. 444 (7116): 184–186. Bibcode:2006Natur.444..184S. doi:10.1038/nature05303. PMID 17093445. S2CID 7679109.
  210. ^ Luciuk, Mike. "How Bright is the Moon?". Amateur Astronomers. Archived from the original on March 12, 2010. Retrieved March 16, 2010.
  211. ^ a b "Colors of the Moon". Science Mission Directorate. November 11, 2020. Archived from the original on April 9, 2022. Retrieved April 9, 2022.
  212. ^ Gibbs, Philip (May 1997). "Why is the sky blue?". math.ucr.edu. Archived from the original on November 2, 2015. Retrieved November 4, 2015. ... may cause the moon to have a blue tinge since the red light has been scattered out.
  213. ^ Espenak, F. (2000). "Solar Eclipses for Beginners". MrEclip. Archived from the original on May 24, 2015. Retrieved March 17, 2010.
  214. ^ Walker, John (July 10, 2004). "Moon near Perigee, Earth near Aphelion". Fourmilab. Archived from the original on December 8, 2013. Retrieved December 25, 2013.
  215. ^ Thieman, J.; Keating, S. (May 2, 2006). "Eclipse 99, Frequently Asked Questions". NASA. Archived from the original on February 11, 2007. Retrieved April 12, 2007.
  216. ^ Espenak, F. "Saros Cycle". NASA. Archived from the original on October 30, 2007. Retrieved March 17, 2010.
  217. ^ Guthrie, D.V. (1947). "The Square Degree as a Unit of Celestial Area". Popular Astronomy. Vol. 55. pp. 200–203. Bibcode:1947PA.....55..200G.
  218. ^ "Total Lunar Occultations". Royal Astronomical Society of New Zealand. Archived from the original on February 23, 2010. Retrieved March 17, 2010.
  219. ^ a b Boyle, Rebecca (July 9, 2019). "Ancient humans used the moon as a calendar in the sky". Science News. Archived from the original on November 4, 2021. Retrieved May 26, 2024.
  220. ^ a b Burton, David M. (2011). The History of Mathematics: An Introduction. Mcgraw-Hill. p. 3. ISBN 978-0077419219.
  221. ^ "Lunar maps". Archived from the original on June 1, 2019. Retrieved September 18, 2019.
  222. ^ "Carved and Drawn Prehistoric Maps of the Cosmos". Space Today. 2006. Archived from the original on March 5, 2012. Retrieved April 12, 2007.
  223. ^ a b c d e Black, Jeremy; Green, Anthony (1992). Gods, Demons and Symbols of Ancient Mesopotamia: An Illustrated Dictionary. The British Museum Press. pp. 54, 135. ISBN 978-0-7141-1705-8. Archived from the original on August 19, 2020. Retrieved October 28, 2017.
  224. ^ "Nebra Sky Disc". State Museum of Prehistory. Retrieved September 27, 2024.
  225. ^ a b Simonova, Michaela (January 2, 2022). "Under the Moonlight: Depictions of the Moon in Art". TheCollector. Retrieved May 26, 2024.
  226. ^ Meller, Harald (2021). "The Nebra Sky Disc – astronomy and time determination as a source of power". Time is power. Who makes time?: 13th Archaeological Conference of Central Germany. Landesmuseum für Vorgeschichte Halle (Saale). ISBN 978-3-948618-22-3.
  227. ^ Concepts of cosmos in the world of Stonehenge. British Museum. 2022.
  228. ^ Bohan, Elise; Dinwiddie, Robert; Challoner, Jack; Stuart, Colin; Harvey, Derek; Wragg-Sykes, Rebecca; Chrisp, Peter; Hubbard, Ben; Parker, Phillip; et al. (Writers) (February 2016). Big History. Foreword by David Christian (1st American ed.). New York: DK. p. 20. ISBN 978-1-4654-5443-0. OCLC 940282526.
  229. ^ O'Connor, J.J.; Robertson, E.F. (February 1999). "Anaxagoras of Clazomenae". University of St Andrews. Archived from the original on January 12, 2012. Retrieved April 12, 2007.
  230. ^ a b c d Needham, Joseph (1986). Science and Civilization in China, Volume III: Mathematics and the Sciences of the Heavens and Earth. Taipei: Caves Books. ISBN 978-0-521-05801-8. Archived from the original on June 22, 2019. Retrieved August 22, 2020.
  231. ^ Aaboe, A.; Britton, J.P.; Henderson, J.A.; Neugebauer, Otto; Sachs, A.J. (1991). "Saros Cycle Dates and Related Babylonian Astronomical Texts". Transactions of the American Philosophical Society. 81 (6): 1–75. doi:10.2307/1006543. JSTOR 1006543. One comprises what we have called "Saros Cycle Texts", which give the months of eclipse possibilities arranged in consistent cycles of 223 months (or 18 years).
  232. ^ Sarma, K.V. (2008). "Astronomy in India". In Helaine Selin (ed.). Encyclopaedia of the History of Science, Technology, and Medicine in Non-Western Cultures (2 ed.). Springer. pp. 317–321. Bibcode:2008ehst.book.....S. ISBN 978-1-4020-4559-2.
  233. ^ Lewis, C.S. (1964). The Discarded Image. Cambridge: Cambridge University Press. p. 108. ISBN 978-0-521-47735-2. Archived from the original on June 17, 2020. Retrieved November 11, 2019.
  234. ^ "Discovering How Greeks Computed in 100 B.C." The New York Times. July 31, 2008. Archived from the original on December 4, 2013. Retrieved March 9, 2014.
  235. ^ van der Waerden, Bartel Leendert (1987). "The Heliocentric System in Greek, Persian and Hindu Astronomy". Annals of the New York Academy of Sciences. 500 (1): 1–569. Bibcode:1987NYASA.500....1A. doi:10.1111/j.1749-6632.1987.tb37193.x. PMID 3296915. S2CID 84491987.
  236. ^ Evans, James (1998). The History and Practice of Ancient Astronomy. Oxford & New York: Oxford University Press. pp. 71, 386. ISBN 978-0-19-509539-5.
  237. ^ Hayashi (2008), "Aryabhata I", Encyclopædia Britannica.
  238. ^ Gola, 5; p. 64 in The Aryabhatiya of Aryabhata: An Ancient Indian Work on Mathematics and Astronomy, translated by Walter Eugene Clark (University of Chicago Press, 1930; reprinted by Kessinger Publishing, 2006). "Half of the spheres of the Earth, the planets, and the asterisms is darkened by their shadows, and half, being turned toward the Sun, is light (being small or large) according to their size."
  239. ^ A.I. Sabra (2008). "Ibn Al-Haytham, Abū ʿAlī Al-Ḥasan Ibn Al-Ḥasan". Dictionary of Scientific Biography. Detroit: Charles Scribner's Sons. pp. 189–210, at 195.
  240. ^ Van Helden, A. (1995). "The Moon". Galileo Project. Archived from the original on June 23, 2004. Retrieved April 12, 2007.
  241. ^ Consolmagno, Guy J. (1996). "Astronomy, Science Fiction and Popular Culture: 1277 to 2001 (And beyond)". Leonardo. 29 (2): 127–132. doi:10.2307/1576348. JSTOR 1576348. S2CID 41861791.
  242. ^ Hall, R. Cargill (1977). "Appendix A: Lunar Theory Before 1964". NASA History Series. Lunar Impact: A History of Project Ranger. Washington, DC: Scientific and Technical Information Office, NASA. Archived from the original on April 10, 2010. Retrieved April 13, 2010.
  243. ^ Zak, Anatoly (2009). "Russia's unmanned missions toward the Moon". Archived from the original on April 14, 2010. Retrieved April 20, 2010.
  244. ^ "Record of Lunar Events, 24 July 1969". Apollo 11 30th anniversary. NASA. Archived from the original on April 8, 2010. Retrieved April 13, 2010.
  245. ^ Coren, M. (July 26, 2004). "'Giant leap' opens world of possibility". CNN. Archived from the original on January 20, 2012. Retrieved March 16, 2010.
  246. ^ "Manned Space Chronology: Apollo_11". Spaceline.org. Archived from the original on February 14, 2008. Retrieved February 6, 2008.
  247. ^ "Apollo Anniversary: Moon Landing "Inspired World"". National Geographic. Archived from the original on February 9, 2008. Retrieved February 6, 2008.
  248. ^ Orloff, Richard W. (September 2004) [First published 2000]. "Extravehicular Activity". NASA History Division, Office of Policy and Plans - Apollo by the Numbers: A Statistical Reference. The NASA History Series. Washington, DC: NASA. ISBN 978-0-16-050631-4. LCCN 00061677. NASA SP-2000-4029. Archived from the original on June 6, 2013. Retrieved August 1, 2013.
  249. ^ "NASA news release 77-47 page 242" (PDF) (Press release). September 1, 1977. Archived (PDF) from the original on June 4, 2011. Retrieved March 16, 2010.
  250. ^ Appleton, James; Radley, Charles; Deans, John; Harvey, Simon; Burt, Paul; Haxell, Michael; Adams, Roy; Spooner N.; Brieske, Wayne (1977). "NASA Turns A Deaf Ear To The Moon". OASI Newsletters Archive. Archived from the original on December 10, 2007. Retrieved August 29, 2007.
  251. ^ Dickey, J.; Bender, P. L.; Faller, J. E.; Newhall, X. X.; Ricklefs, R. L.; Ries, J. G.; Shelus, P. J.; Veillet, C.; Whipple, A. L. (1994). "Lunar laser ranging: a continuing legacy of the Apollo program". Science. 265 (5171): 482–490. Bibcode:1994Sci...265..482D. doi:10.1126/science.265.5171.482. PMID 17781305. S2CID 10157934.
  252. ^ "Rocks and Soils from the Moon". NASA. Archived from the original on May 27, 2010. Retrieved April 6, 2010.
  253. ^ "Hiten-Hagomoro". NASA. Archived from the original on June 14, 2011. Retrieved March 29, 2010.
  254. ^ "Clementine information". NASA. 1994. Archived from the original on September 25, 2010. Retrieved March 29, 2010.
  255. ^ "Lunar Prospector: Neutron Spectrometer". NASA. 2001. Archived from the original on May 27, 2010. Retrieved March 29, 2010.
  256. ^ "SMART-1 factsheet". European Space Agency. February 26, 2007. Archived from the original on March 23, 2010. Retrieved March 29, 2010.
  257. ^ "Chang'e 1". NASA. 2019. Archived from the original on November 22, 2021. Retrieved October 3, 2021.
  258. ^ "Mission Sequence". Indian Space Research Organisation. November 17, 2008. Archived from the original on July 6, 2010. Retrieved April 13, 2010.
  259. ^ "Lunar CRater Observation and Sensing Satellite (LCROSS): Strategy & Astronomer Observation Campaign". NASA. October 2009. Archived from the original on January 1, 2012. Retrieved April 13, 2010.
  260. ^ David, Leonard (March 17, 2015). "China Outlines New Rockets, Space Station and Moon Plans". Space.com. Archived from the original on July 1, 2016. Retrieved June 29, 2016.
  261. ^ "China's Chang'e-5 brought 1,731 grams of samples from the moon". The Hindu. December 20, 2020. Archived from the original on October 29, 2021. Retrieved October 15, 2021.
  262. ^ "President Bush Offers New Vision For NASA" (Press release). NASA. December 14, 2004. Archived from the original on May 10, 2007. Retrieved April 12, 2007.
  263. ^ Mann, Adam (July 2019). "NASA's Artemis Program". Space.com. Archived from the original on April 17, 2021. Retrieved April 19, 2021.
  264. ^ a b c "The Space Review: The Artemis Accords: repeating the mistakes of the Age of Exploration". The Space Review. June 29, 2020. Archived from the original on January 25, 2022. Retrieved February 1, 2022.
  265. ^ a b "Australia Between the Moon Agreement and the Artemis Accords". Australian Institute of International Affairs. June 2, 2021. Archived from the original on February 1, 2022. Retrieved February 1, 2022.
  266. ^ a b c "The Space Treaty Institute – Dedicated to Peace and Sustainability in Outer Space. Our Mission: To give people Hope and Inspiration by helping the nations of Earth to build a Common Future". The Space Treaty Institute – Dedicated to Peace and Sustainability in Outer Space. Our Mission. Archived from the original on February 1, 2022. Retrieved February 1, 2022.
  267. ^ "Japan makes contact with 'Moon Sniper' on lunar surface". BBC News. January 19, 2024. Archived from the original on January 19, 2024. Retrieved January 19, 2024.
  268. ^ Robert Lea (April 24, 2024). "Japan's SLIM moon lander defies death to survive 3rd frigid lunar night (image)". Space.com. Archived from the original on April 30, 2024. Retrieved May 1, 2024.
  269. ^ "Intuitive Machines' 'Odysseus' becomes first commercial lander to reach the Moon – Spaceflight Now". Archived from the original on June 15, 2024. Retrieved April 15, 2024.
  270. ^ Andrew Jones [@AJ_FI] (April 25, 2023). "China's Chang'e-6 sample return mission (a first ever lunar far side sample-return) is scheduled to launch in May 2024, and expected to take 53 days from launch to return module touchdown. Targeting southern area of Apollo basin (~43º S, 154º W)" (Tweet) – via Twitter.
  271. ^ Jones, Andrew (May 6, 2024). "China's Chang'e-6 is carrying a surprise rover to the moon". SpaceNews. Archived from the original on May 8, 2024. Retrieved May 8, 2024.
  272. ^ Jones, Andrew (January 10, 2024). "China's Chang'e-6 probe arrives at spaceport for first-ever lunar far side sample mission". SpaceNews. Archived from the original on May 3, 2024. Retrieved January 10, 2024.
  273. ^ "NASA plans to send first woman on Moon by 2024". The Asian Age. May 15, 2019. Archived from the original on April 14, 2020. Retrieved May 15, 2019.
  274. ^ "Russia, China agree on joint Moon exploration". TASS. September 17, 2019. Archived from the original on July 22, 2023. Retrieved April 16, 2024.
  275. ^ Covault, C. (June 4, 2006). "Russia Plans Ambitious Robotic Lunar Mission". Aviation Week. Archived from the original on June 12, 2006. Retrieved April 12, 2007.
  276. ^ Bantock, Jack (April 24, 2024). "Streaming and texting on the Moon: Nokia and NASA are taking 4G into space | CNN Business". CNN. Archived from the original on April 27, 2024. Retrieved April 27, 2024.
  277. ^ Meredith Garofalo (December 8, 2023). "DARPA moon tech study selects 14 companies to develop a lunar economy". Space.com. Archived from the original on June 15, 2024. Retrieved April 27, 2024.
  278. ^ Williams, Matt (May 14, 2022). "A CubeSat is Flying to the Moon to Make Sure Lunar Gateway's Orbit is Actually Stable". Universe Today. Archived from the original on December 17, 2022. Retrieved December 17, 2022.
  279. ^ "Queqiao: The bridge between Earth and the far side of the moon". Phys.org. June 11, 2021. Archived from the original on December 17, 2022. Retrieved December 17, 2022.
  280. ^ a b Garber, Megan (December 19, 2012). "The Trash We've Left on the Moon". The Atlantic. Archived from the original on April 9, 2022. Retrieved April 11, 2022.
  281. ^ Vidaurri, Monica (October 24, 2019). "Will people go to space—and then colonize it?". Quartz. Archived from the original on November 9, 2021. Retrieved November 9, 2021.
  282. ^ David, Leonard (August 21, 2020). "Cold as (lunar) ice: Protecting the moon's polar regions from contamination". Space.com. Archived from the original on February 4, 2022. Retrieved February 3, 2022.
  283. ^ Gorman, Alice (July 1, 2022). "#SpaceWatchGL Opinion: An ecofeminist approach to the sustainable use of the Moon". SpaceWatch.Global. Archived from the original on July 4, 2022. Retrieved July 3, 2022. Note: see Val Plumwood which Alice Gorman cites regarding co-participation.
  284. ^ a b c Alvarez, Tamara (January 1, 2020). The Eighth Continent: An Ethnography of Twenty-First Century Euro-American Plans to Settle the Moon (Thesis). p. 109-115, 164–167, 176. Archived from the original on February 5, 2022. Retrieved November 1, 2021.
  285. ^ Carter, Jamie (February 27, 2022). "As Chinese Rocket Strikes Moon This Week We Need To Act Now To Prevent New Space Junk Around The Moon Say Scientists". Forbes. Archived from the original on April 9, 2022. Retrieved April 9, 2022.
  286. ^ a b "Space: The Final Frontier of Environmental Disasters?". Wired. July 15, 2013. Archived from the original on July 14, 2021. Retrieved April 9, 2022.
  287. ^ Pino, Paolo; Salmeri, Antonino; Hugo, Adam; Hume, Shayna (August 27, 2021). "Waste Management for Lunar Resources Activities: Toward a Circular Lunar Economy". New Space. 10 (3). Mary Ann Liebert Inc: 274–283. doi:10.1089/space.2021.0012. ISSN 2168-0256. S2CID 233335692.
  288. ^ Briggs, Randall; Sacco, Albert (1985). "1985lbsa.conf..423B Page 423". Lunar Bases and Space Activities of the 21st Century (in Finnish): 423. Bibcode:1985lbsa.conf..423B. Archived from the original on May 26, 2022. Retrieved May 26, 2022.
  289. ^ Magazine, Smithsonian; Sullivan, Will (January 5, 2024). "Navajo Nation President Asks for Delay of Moon Mission Carrying Human Remains". Smithsonian Magazine. Archived from the original on January 6, 2024. Retrieved January 7, 2024.
  290. ^ "Celestis Memorial Spaceflights". August 8, 2011. Archived from the original on March 14, 2014. Retrieved January 7, 2024.{{cite web}}: CS1 maint: unfit URL (link)
  291. ^ Andrew Jones (September 23, 2020). "China's Chang'e 3 lunar lander still going strong after 7 years on the moon". Space.com. Archived from the original on November 25, 2020. Retrieved November 16, 2020.
  292. ^ Takahashi, Yuki (September 1999). "Mission Design for Setting up an Optical Telescope on the Moon". California Institute of Technology. Archived from the original on November 6, 2015. Retrieved March 27, 2011.
  293. ^ Chandler, David (February 15, 2008). "MIT to lead development of new telescopes on moon". MIT News. Archived from the original on March 4, 2009. Retrieved March 27, 2011.
  294. ^ Naeye, Robert (April 6, 2008). "NASA Scientists Pioneer Method for Making Giant Lunar Telescopes". Goddard Space Flight Center. Archived from the original on December 22, 2010. Retrieved March 27, 2011.
  295. ^ Bell, Trudy (October 9, 2008). "Liquid Mirror Telescopes on the Moon". Science News. NASA. Archived from the original on March 23, 2011. Retrieved March 27, 2011.
  296. ^ "Far Ultraviolet Camera/Spectrograph". Lpi.usra.edu. Archived from the original on December 3, 2013. Retrieved October 3, 2013.
  297. ^ Gorkavyi, Nick; Krotkov, Nickolay; Marshak, Alexander (March 24, 2023). "Earth observations from the Moon's surface: dependence on lunar libration". Atmospheric Measurement Techniques. 16 (6). Copernicus GmbH: 1527–1537. Bibcode:2023AMT....16.1527G. doi:10.5194/amt-16-1527-2023. ISSN 1867-8548. S2CID 257753776.
  298. ^ "Mission Report: Apollo 17 – The Most Productive Lunar Expedition" (PDF). NASA. Archived from the original (PDF) on September 30, 2006. Retrieved February 10, 2021.
  299. ^ a b David, Leonard (October 21, 2019). "Moon Dust Could Be a Problem for Future Lunar Explorers". Space.com. Archived from the original on December 1, 2020. Retrieved November 26, 2020.
  300. ^ Zheng, William (January 15, 2019). "Chinese lunar lander's cotton seeds spring to life on far side of the moon". South China Morning Post. Archived from the original on January 16, 2019. Retrieved November 26, 2020.
  301. ^ a b "Can any State claim a part of outer space as its own?". United Nations Office for Outer Space Affairs. Archived from the original on April 21, 2010. Retrieved March 28, 2010.
  302. ^ "The treaties control space-related activities of States. What about non-governmental entities active in outer space, like companies and even individuals?". United Nations Office for Outer Space Affairs. Archived from the original on April 21, 2010. Retrieved March 28, 2010.
  303. ^ "Statement by the Board of Directors of the IISL On Claims to Property Rights Regarding The Moon and Other Celestial Bodies (2004)" (PDF). International Institute of Space Law. 2004. Archived from the original on December 22, 2009. Retrieved March 28, 2010.{{cite web}}: CS1 maint: unfit URL (link)
  304. ^ "Further Statement by the Board of Directors of the IISL On Claims to Lunar Property Rights (2009)" (PDF). International Institute of Space Law. March 22, 2009. Archived from the original on December 22, 2009. Retrieved March 28, 2010.{{cite web}}: CS1 maint: unfit URL (link)
  305. ^ "Do the five international treaties regulate military activities in outer space?". United Nations Office for Outer Space Affairs. Archived from the original on April 21, 2010. Retrieved March 28, 2010.
  306. ^ "How many States have signed and ratified the five international treaties governing outer space?". United Nations Office for Outer Space Affairs. January 1, 2006. Archived from the original on April 21, 2010. Retrieved March 28, 2010.
  307. ^ a b "The Space Review: Is outer space a de jure common-pool resource?". The Space Review. October 25, 2021. Archived from the original on November 2, 2021. Retrieved April 9, 2022.
  308. ^ "Agreement Governing the Activities of States on the Moon and Other Celestial Bodies". United Nations Office for Outer Space Affairs. Archived from the original on August 9, 2010. Retrieved March 28, 2010.
  309. ^ Vazhapully, Kiran (July 22, 2020). "Space Law at the Crossroads: Contextualizing the Artemis Accords and the Space Resources Executive Order". OpinioJuris. Archived from the original on May 10, 2021. Retrieved May 10, 2021.
  310. ^ "Administration Statement on Executive Order on Encouraging International Support for the Recovery and Use of Space Resources" (Press release). White House. April 6, 2020. Archived from the original on February 1, 2024. Retrieved June 17, 2020 – via SpaceRef.
  311. ^ "'One Small Step' Act Encourages Protection of Human Heritage in Space". HowStuffWorks. January 12, 2021. Archived from the original on November 1, 2021. Retrieved November 1, 2021.
  312. ^ "Moonkind – Human Heritage in Outer Space". For All Moonkind. Archived from the original on November 1, 2021. Retrieved November 1, 2021.
  313. ^ a b "Declaration of the Rights of the Moon". Australian Earth Laws Alliance. February 11, 2021. Archived from the original on April 23, 2021. Retrieved May 10, 2021.
  314. ^ Tepper, Eytan; Whitehead, Christopher (December 1, 2018). "Moon, Inc.: The New Zealand Model of Granting Legal Personality to Natural Resources Applied to Space". New Space. 6 (4): 288–298. Bibcode:2018NewSp...6..288T. doi:10.1089/space.2018.0025. ISSN 2168-0256. S2CID 158616075. Archived from the original on June 28, 2021. Retrieved July 30, 2022.
  315. ^ a b Evans, Kate (July 20, 2021). "Hear Ye! Hear Ye! A Declaration of the Rights of the Moon". Eos. Archived from the original on February 6, 2022. Retrieved April 9, 2022.
  316. ^ Thompson, William Irwin. (1981). The time falling bodies take to light : mythology, sexuality, and the origins of culture. New York: St. Martin's Press. p. 105. ISBN 0-312-80510-1. OCLC 6890108. Archived from the original on October 3, 2021. Retrieved July 30, 2022.
  317. ^ Boyle, Rebecca (July 9, 2019). "Ancient humans used the moon as a calendar in the sky". Science News. Archived from the original on November 4, 2021. Retrieved November 4, 2021.
  318. ^ Brooks, A. S.; Smith, C. C. (1987). "Ishango revisited: new age determinations and cultural interpretations". The African Archaeological Review. 5 (1): 65–78. doi:10.1007/BF01117083. JSTOR 25130482. S2CID 129091602.
  319. ^ Duncan, David Ewing (1998). The Calendar. Fourth Estate Ltd. pp. 10–11. ISBN 978-1-85702-721-1.
  320. ^ Zerubavel, E. (1989). The Seven Day Circle: The History and Meaning of the Week. University of Chicago Press. p. 9. ISBN 978-0-226-98165-9. Archived from the original on July 25, 2022. Retrieved February 25, 2022.
  321. ^ Smith, William George (1849). Dictionary of Greek and Roman Biography and Mythology: Oarses-Zygia. Vol. 3. J. Walton. p. 768. Archived from the original on November 26, 2020. Retrieved March 29, 2010.
  322. ^ Estienne, Henri (1846). Thesaurus graecae linguae. Vol. 5. Didot. p. 1001. Archived from the original on July 28, 2020. Retrieved March 29, 2010.
  323. ^ mensis. Charlton T. Lewis and Charles Short. A Latin Dictionary on Perseus Project.
  324. ^ μείς in Liddell and Scott.
  325. ^ Mallory, J.P.; Adams, D.Q. (2006). The Oxford Introduction to Proto-Indo-European and the Proto-Indo-European World. Oxford Linguistics. Oxford University Press. pp. 98, 128, 317. ISBN 978-0-19-928791-8.
  326. ^ Harper, Douglas. "measure". Online Etymology Dictionary.
  327. ^ Harper, Douglas. "menstrual". Online Etymology Dictionary.
  328. ^ Ilyas, Mohammad (March 1994). "Lunar Crescent Visibility Criterion and Islamic Calendar". Quarterly Journal of the Royal Astronomical Society. 35: 425. Bibcode:1994QJRAS..35..425I.
  329. ^ "Mid-Autumn Festival Celebration". Confucius Institute for Scotland. August 30, 2022. Archived from the original on November 22, 2022. Retrieved November 22, 2022.
  330. ^ a b "Cylinder vase". Collections Search – Museum of Fine Arts, Boston. May 20, 1987. Archived from the original on November 11, 2021. Retrieved November 11, 2021.
  331. ^ Hart, G. (2005). The Routledge Dictionary of Egyptian Gods and Goddesses. Routledge Dictionaries. Taylor & Francis. p. 77. ISBN 978-1-134-28424-5. Archived from the original on July 25, 2022. Retrieved February 23, 2022.
  332. ^ a b c Nemet-Nejat, Karen Rhea (1998). Daily Life in Ancient Mesopotamia. Greenwood. p. 203. ISBN 978-0-313-29497-6. Archived from the original on June 16, 2020. Retrieved June 11, 2019.
  333. ^ Zschietzschmann, W. (2006). Hellas and Rome: The Classical World in Pictures. Whitefish, Montana: Kessinger Publishing. p. 23. ISBN 978-1-4286-5544-7.
  334. ^ Cohen, Beth (2006). "Outline as a Special Technique in Black- and Red-figure Vase-painting". The Colors of Clay: Special Techniques in Athenian Vases. Los Angeles: Getty Publications. pp. 178–179. ISBN 978-0-89236-942-3. Archived from the original on August 19, 2020. Retrieved April 28, 2020.
  335. ^ "It seems possible, though not certain, that after the conquest Mehmed took over the crescent and star as an emblem of sovereignty from the Byzantines. The half-moon alone on a blood red flag, allegedly conferred on the Janissaries by Emir Orhan, was much older, as is demonstrated by numerous references to it dating from before 1453. But since these flags lack the star, which along with the half-moon is to be found on Sassanid and Byzantine municipal coins, it may be regarded as an innovation of Mehmed. It seems certain that in the interior of Asia tribes of Turkish nomads had been using the half-moon alone as an emblem for some time past, but it is equally certain that crescent and star together are attested only for a much later period. There is good reason to believe that old Turkish and Byzantine traditions were combined in the emblem of Ottoman and, much later, present-day Republican Turkish sovereignty." Franz Babinger (William C. Hickman Ed., Ralph Manheim Trans.), Mehmed the Conqueror and His Time, Princeton University Press, 1992, p 108
  336. ^ Kadoi, Yuka (October 1, 2014). "Crescent (symbol of Islam)". Brill Encyclopedia of Islam Online. Archived from the original on April 8, 2022. Retrieved April 8, 2022.
  337. ^ Abbri, Ferdinando (August 30, 2019). "Gold and silver: perfection of metals in medieval and early modern alchemy". Substantia: 39–44. doi:10.13128/Substantia-603. ISSN 2532-3997. Archived from the original on June 17, 2022. Retrieved April 8, 2022.
  338. ^ "Muhammad." Encyclopædia Britannica. 2007. Encyclopædia Britannica Online, p.13
  339. ^ a b "Imagining the Moon". The New York Times. July 9, 2019. Archived from the original on July 9, 2019. Retrieved November 4, 2021.
  340. ^ "The Moon of Science or the Moon of Lovers?". The MIT Press Reader. September 29, 2020. Archived from the original on November 1, 2021. Retrieved November 1, 2021.
  341. ^ Seed, David (July 9, 2019). "Moon on the mind: two millennia of lunar literature". Nature. 571 (7764): 172–173. Bibcode:2019Natur.571..172S. doi:10.1038/d41586-019-02090-w. S2CID 195847287.
  342. ^ "Polycentricity for Governance of the Moon as a Commons". Open Lunar Foundation. March 22, 2022. Archived from the original on April 20, 2022. Retrieved April 9, 2022.
  343. ^ Nations, United (October 10, 1967). "International Moon Day". United Nations. Archived from the original on June 27, 2023. Retrieved November 8, 2023.
  344. ^ a b Lilienfeld, Scott O.; Arkowitz, Hal (2009). "Lunacy and the Full Moon". Scientific American. Archived from the original on October 16, 2009. Retrieved April 13, 2010.
  345. ^ Rotton, James; Kelly, I.W. (1985). "Much ado about the full moon: A meta-analysis of lunar-lunacy research". Psychological Bulletin. 97 (2): 286–306. doi:10.1037/0033-2909.97.2.286. PMID 3885282.
  346. ^ Martens, R.; Kelly, I.W.; Saklofske, D.H. (1988). "Lunar Phase and Birthrate: A 50-year Critical Review". Psychological Reports. 63 (3): 923–934. doi:10.2466/pr0.1988.63.3.923. PMID 3070616. S2CID 34184527.
  347. ^ Kelly, Ivan; Rotton, James; Culver, Roger (1986). "The Moon Was Full and Nothing Happened: A Review of Studies on the Moon and Human Behavior". Skeptical Inquirer. 10 (2): 129–143. Reprinted in The Hundredth Monkey – and other paradigms of the paranormal, edited by Kendrick Frazier, Prometheus Books. Revised and updated in The Outer Edge: Classic Investigations of the Paranormal, edited by Joe Nickell, Barry Karr, and Tom Genoni, 1996, CSICOP.
  348. ^ Foster, Russell G.; Roenneberg, Till (2008). "Human Responses to the Geophysical Daily, Annual and Lunar Cycles". Current Biology. 18 (17): R784–R794. Bibcode:2008CBio...18.R784F. doi:10.1016/j.cub.2008.07.003. PMID 18786384. S2CID 15429616.

Further reading

Cartographic resources