History UsefulNotes / TheMoon

* The Walter Koenig vehicle ''Film/{{Moontrap}}'' involves alien intelligences lying in wait on the Moon.

As can be seen even on a casual glance with binoculars, the Moon's surface is covered in craters, caused by comet and asteroid impacts in the ancient (and occasionally recent) past, and ranging in size from tiny craterlets seen with microscopes in the lunar rocks brought by space missions to large basins with concentric rings of mountains and sizes of up to 2,500 kilometres (the South Pole-Aitken Basin, one of the largest impact craters known in the Solar System). Each of those craters has a name; most are named after scientists and philosophers. For instance, the great big crater with the huge white rays coming out of it in all directions is Tycho Crater, named after [[http://en.wikipedia.org/wiki/Tycho_Brahe Tycho Brahe]]. The moon's surface is also partially covered by "Seas" (''maria'' in [[GratuitousLatin Latin]]), [[TheArtifact a relic]] of the early days of telescopic observation when they were thought to be large masses of water; they're actually dark areas where ancient volcanoes spilled lava all over the place, in most cases corresponding to ''big'' craters similar to the already mentioned South Pole-Aitken Basin but smaller, excavated by [[ColonyDrop massive asteroid impacts]]. Like the craters, each Sea has a name, but unlike the craters, the Sea names are derived from things that sailors might be concerned about-- the Sea of Tranquility[[note]]Mare Tranquillitatis[[/note]], the Sea of Rains[[note]]Mare Imbrium[[/note]], the Sea of Fecundity[[note]]Mare Fecunditatis[[/note]], etc. Another interesting note is that the Moon ''does'' have a thin atmosphere, called an "exosphere". It's visible when there's a new moon and the Moon shows off a sulfurous "tail".[[note]][[http://time.com/4974580/nasa-moon-had-atmosphere-volcanoes/ Studies]] of the rocks brought back by the "Apollo" missions show that, between 3 and 4 billion years ago, the Moon had an atmosphere twice as thick as Mars' current one produced by volcanism, which was stripped away by the solar wind.[[/note]]

Compared to other moons in UsefulNotes/{{the Solar System}}, Earth's Moon is really huge compared with the planet it orbits, weighing in at a whopping 1/81 of Earth's mass and 1/6 of Earth's surface gravity. By comparison, even [[UsefulNotes/TheMoonsOfSaturn the largest moon of Saturn]] is only 1/4000 of {{UsefulNotes/Saturn}}'s mass. The Moon also has roughly 2/9 the mass of {{UsefulNotes/Mercury}}, and is about 1.8 times more massive than all five recognized dwarf planets (Eris, Pluto, Makemake, Haumea, and Ceres), Pluto's satellite Charon (which is more massive than Ceres), and the Asteroid Belt (Ceres excluded) ''combined''. Among UsefulNotes/{{the moons of Jupiter}} and Saturn, only Ganymede, Titan, Callisto, and Io are more massive than the Moon, and only Io is dense enough to have a higher surface gravity than the Moon. The Moon is so large in comparison to the Earth that the center of gravity between the two is about two thirds of the Earth's radius out from its center, causing the Earth to noticeably wobble around it. This has led some to believe the Earth-Moon system should be considered a double planet, although this is heavily disputed due to the fact that the center of gravity remains within Earth's interior.

The Moon is also the major cause of tides on the Earth. When the Moon is directly above you or directly below you (i.e., on the opposite side of the Earth), tides are highest; when it's 90 degrees off to one side of you, tides are lowest. UsefulNotes/TheSun also causes tides, but these tides are much weaker than the Moon's.

As can be seen even on a casual glance with binoculars, the Moon's surface is covered in craters, caused by comet and asteroid impacts in the ancient (and, occasionally, recent) past and that range in size from tiny craterlets seen with microscopes in the lunar rocks brought by space missions to large basins with concentric rings of mountains and sizes of up to 2,500 kilometres (the South Pole-Aitken Basin, one of the largest impact craters known in the Solar System). Each of those craters has a name, and most are named after scientists and philosophers. For instance, the great big crater with the huge white rays coming out of it in all directions is Tycho Crater, named after [[http://en.wikipedia.org/wiki/Tycho_Brahe Tycho Brahe]]. The moon's surface is also partially covered by "Seas" (''maria'' in [[GratuitousLatin Latin]]), [[TheArtifact a relic]] of the early days of telescopic observation when they were thought to be large masses of water, dark areas where ancient volcanoes spilled lava all over the place and that in most cases correspond to ''big'' craters similar to the already mentioned South Pole-Aitken Basin but smaller, excavated by [[ColonyDrop massive asteroid impacts]]. Like the craters, each Sea has a name, but unlike the craters the Sea names are derived from things that sailors might be concerned about -- the Sea of Tranquility,[[note]]Mare Tranquillitatis[[/note]] the Sea of Rains,[[note]]Mare Imbrium[[/note]] the Sea of Fecundity,[[note]]Mare Fecunditatis[[/note]] etc. Another interesting note is that the Moon ''does'' have a thin atmosphere, called an "exosphere". It's visible when there's a new moon and the Moon shows off a sulfurous "tail".[[note]][[http://time.com/4974580/nasa-moon-had-atmosphere-volcanoes/ Studies]] of the rocks brought back by the "Apollo" missions show the Moon to have had between 3 and 4 billion years ago an atmosphere twice as thick as Mars' current one produced by volcanism, that was stripped away by the solar wind.[[/note]]

Despite how bright the Moon may appear in the night sky, its surface is very, very dark. Its albedo is a dismal 7%, which means that 93% of all incident light is absorbed without being reflected back into space. For comparison, Earth's albedo is around 38%. The difference in color between the light-colored regolith and the dark-colored maria is like the difference between coal dust and ''extra-dark'' coal dust.[[note]]However, the night sky is even darker, and that contrast causes the Moon to stand out considerably.[[/note]] Moonlight is also not bluish or silver but [[https://physics.stackexchange.com/questions/244922/why-does-moonlight-have-a-lower-color-temperature actually redder]] than sunlight with us seeing it with the former colors due to the way our eyes [[https://en.wikipedia.org/wiki/Purkinje_effect work]] in low-light conditions.

Since the Moon keeps the same face pointed toward Earth at all times, the far side of the Moon can't be seen from the Earth's surface,[[note]][[https://en.wikipedia.org/wiki/Libration Lunar librations]] allow us to see a bit of the lunar far side[[/note]] and it wasn't until the advent of the first space probes that we had any idea what the far side looked like. (It's got a lot less maria and a lot more craters than the near side; the slightly greater density of the dark maria material may be why the maria-rich side ended up facing Earth.) Both the near side and the far side wax and wane through light-and-dark phases, so it's incorrect to call the far side "Music/TheDarkSideOfTheMoon" except during the brief period every month while the Moon appears Full in Earth's skies.

Sadly, the Moon will not be with us forever. Those same tidal forces that pull on the Earth's oceans and locked the same face of the Moon toward the Earth are also, very slowly, widening the Moon's orbit.[[note]]Currently, every year the Moon is about 2 inches farther away than the year prior.[[/note]] In a short time (on a geological scale, at least), the Moon will be too far away to cause total solar eclipses.[[note]]Which actually results in an interesting phenomenon: we are currently in a phase of the Moon's orbital life that results in the Moon ''just'' being able to cover up the Sun during an eclipse. For the dinosaurs, though, the Moon would've completely blocked out the Sun easily.[[/note]] Eventually, it will be far enough away to leave Earth orbit entirely, and wander through space just like in ''Series/Space1999'', though by the time that will actually happen, the Sun will have expanded into a red giant and engulfed the Earth already.[[note]]However, the tides caused by the Moon are slowing down Earth's rotation and in theory in the far future our planet could end instead being tidally locked to the Moon. After this happens, it has been proposed that tides caused by the Sun could cause the Moon to approach our planet again -- very slowly -- until it gets [[https://en.wikipedia.org/wiki/Roche_limit so close]] that it's destroyed by Earth's gravity, becoming a ring system similar to Saturn's one but much smaller and denser. Note that those points are just academical since it's unlikely both the Earth and the Moon will survive the Sun's expansion into a red giant up to the Moon ending up destroyed that way due to interactions with the Sun's bloated atmosphere, and they'd take place in a far longer timescale.[[/note]]

Compared to other moons in UsefulNotes/{{the Solar System}}, Earth's Moon is really huge compared with the planet it orbits, weighing in at a whopping 1/81 of Earth's mass and 1/6 of Earth's surface gravity. By comparison, even [[UsefulNotes/TheMoonsOfSaturn the largest moon of Saturn]] is only 1/4000 of {{UsefulNotes/Saturn}}'s mass. The Moon also has roughly 2/9 the mass of {{UsefulNotes/Mercury}}, and is about 1.8 times more massive than all five recognized dwarf planets (Eris, Pluto, Makemake, Haumea, and Ceres), Pluto's satellite Charon (which is more massive than Ceres), and the Asteroid Belt (Ceres excluded) ''combined''. Among UsefulNotes/{{the moons of Jupiter}} and Saturn, only Ganymede, Titan, Callisto, and Io are more massive than the Moon. Of them only Io is dense enough to have a higher surface gravity than the Moon. The Moon is so large in comparison to the Earth that the center of gravity between the two is about two thirds of the Earth's radius out from its center, causing the Earth to noticeably wobble around it. This has led some to believe the Earth-Moon system should be considered a double planet, although this is heavily disputed due to the fact that the center of gravity remains within Earth's interior.

-->--'''UsefulNotes/JohnFKennedy''''s "Address at Rice University on [[UsefulNotes/{{NASA}} the Nation's Space Effort]]"

UsefulNotes/{{Earth}}'s only — or at least, only significant — natural satellite. That we call it ''the'' Moon testifies to its discovery long before any others. In English, it is sometimes called by its Roman name, '''Luna''', when differentiating it with the other satellites in the Solar System. It has been named Selene, Cynthia, and Diane by the Roman and Greek ancients as well. Of course, this is where the word "lunar" comes from, as well as the Greek prefix seleno- (e.g selenophobia, fear of the Moon.)

It orbits our planet some 400,000 kilometers away, taking 27.3 days to go all the way around once. Since the Earth will have moved some distance around UsefulNotes/{{the Sun}} by the time the Moon has orbited once, it takes a little longer — 29.5 days total, to be precise — for the lunar light-cycle to get back around to the same phase it started in. You will note that this is approximately one month, which is no coincidence. Tidal forces long ago caused the Moon to lock in synchronous rotation with the Earth, so that the same side is always facing us.

Currently, our best guess at how such a humongous companion came into existence is that a UsefulNotes/{{Mars}}-sized planetesimal struck the Earth early in its formation period, which knocked loose a huge chunk of material that eventually cooled, congealed, and settled into the Moon's current nearly-circular orbit. New discoveries support this theory, as scientists have found evidence that the Moon was tidally locked only a hundred days after the collision, "baking" one side of the Moon, with the other side thickening from the vaporized crust, explaining the odd crust dichotomy of the satellite. In addition, the Moon and the Earth share the exact same isotopes. Even more amazingly, the "strange lights" that have been seen in the last few decades are probable indication that the Moon's core is NotQuiteDead, such as the flashes of light from Aristarchus, one of the ancient lunar volcanoes. In reality, instead of being UFO's, it's actually the heated expulsion of dust from the Moon's crust.

The Moon has been with us since before the dawn of the human race, progressing through its utterly predictable phases night after night. For most of human prehistory, it was the only light source available to us at night, which lent it a good deal of mystique. Lunar deities are almost as prevalent as solar deities in {{mythology}}. The fact that the Moon's 29-and-a-half-day light cycle is very similar in duration to the average [[WomensMysteries woman's menstrual cycle]] has also not escaped the notice of poets, philosophers, and biologists; indeed the moon is often associated with femininity in literature and myth. However, there are more ''male'' lunar deities than female lunar deities. While Greeks and Romans considered the moon a woman, to the Germanic peoples it apparently was a man, which is how we get TheManInTheMoon.

The Moon is also the major cause of tides on the Earth. When the Moon is directly above you or directly below you (i.e. on the opposite side of the Earth), tides are highest; when it's 90 degrees off to one side of you, tides are lowest. UsefulNotes/TheSun also causes tides, but these tides are much weaker than the Moon's.

As can be seen even on a casual glance with binoculars, the Moon's surface is covered in craters, caused by comet and asteroid impacts in the ancient (and, occasionally, recent) past and that range in size from tiny craterlets seen with microscopes in the lunar rocks brought by space missions to large basins with concentric rings of mountains and sizes of up to 2,500 kilometres (the South Pole-Aitken Basin, one of the largest impact craters known in the Solar System). Each of those craters has a name, and most are named after scientists and philosophers. For instance, the great big crater with the huge white rays coming out of it in all directions is Tycho Crater, named after [[http://en.wikipedia.org/wiki/Tycho_Brahe Tycho Brahe]]. The moon's surface is also partially covered by "Seas" (''maria'' in [[GratuitousLatin Latin]]), [[TheArtifact a relic]] of the early days of telescopic observation when they were thought to be large masses of water, dark areas where ancient volcanoes spilled lava all over the place and that in most cases correspond to ''big'' craters similar to the already mentioned South Pole-Aitken Basin but smaller, excavated by [[ColonyDrop massive asteroid impacts]]. Like the craters, each Sea has a name, but unlike the craters the Sea names are derived from things that sailors might be concerned about — the Sea of Tranquility[[note]]Mare Tranquillitatis[[/note]], the Sea of Rains[[note]]Mare Imbrium[[/note]], the Sea of Fecundity[[note]]Mare Fecunditatis[[/note]], etc. Another interesting note is that the Moon ''does'' have a thin atmosphere, called an "exosphere". It's visible when there's a new moon and the Moon shows off a sulfurous "tail"[[note]][[http://time.com/4974580/nasa-moon-had-atmosphere-volcanoes/ Studies]] of the rocks brought back by the "Apollo" missions show the Moon to have had between 3 and 4 billion years ago an atmosphere twice as thick as Mars' current one produced by volcanism, that was stripped away by the solar wind[[/note]]

Despite how bright the Moon may appear in the night sky, its surface is very, very dark. Its albedo is a dismal 7%, which means that 93% of all incident light is absorbed without being reflected back into space. For comparison, Earth's albedo is around 38%. The difference in color between the light-colored regolith and the dark-colored maria is like the difference between coal dust and ''extra-dark'' coal dust[[note]]However the night sky is even darker, and that contrast causes the Moon to stand out considerably[[/note]]. Moonlight is also not bluish or silver but [[https://physics.stackexchange.com/questions/244922/why-does-moonlight-have-a-lower-color-temperature actually redder]] than sunlight with us seeing it with the former colors due to the way our eyes [[https://en.wikipedia.org/wiki/Purkinje_effect work]] in low-light conditions.

Since the Moon keeps the same face pointed toward Earth at all times, the far side of the Moon can't be seen from the Earth's surface[[note]][[https://en.wikipedia.org/wiki/Libration Lunar librations]] allow us to see a bit of the lunar far side[[/note]] and it wasn't until the advent of the first space probes that we had any idea what the far side looked like. (It's got a lot less maria and a lot more craters than the near side; the slightly greater density of the dark maria material may be why the maria-rich side ended up facing Earth.) Both the near side and the far side wax and wane through light-and-dark phases, so it's incorrect to call the far side "Music/TheDarkSideOfTheMoon" except during the brief period every month while the Moon appears Full in Earth's skies.

Sadly, the Moon will not be with us forever. Those same tidal forces that pull on the Earth's oceans and locked the same face of the Moon toward the Earth are also, very slowly, widening the Moon's orbit. [[note]]Currently, every year the Moon is about 2 inches farther away than the year prior.[[/note]] In a short time (on a geological scale, at least), the Moon will be too far away to cause total solar eclipses. [[note]]Which actually results in a interesting phenomenon: we are currently in a phase of the Moon's orbital life that results in the Moon ''just'' being able to cover up the Sun during an eclipse. For the dinosaurs, though, the Moon would've completely blocked out the Sun easily.[[/note]] Eventually, it will be far enough away to leave Earth orbit entirely, and wander through space just like in ''Series/{{Space 1999}}'', though by the time that will actually happen, the Sun will have expanded into a red giant and engulfed the Earth already.[[note]]However, the tides caused by the Moon are slowing down Earth's rotation and in theory in the far future our planet could end instead being tidally locked to the Moon. After this happens, it has been proposed that tides caused by the Sun could cause the Moon to approach our planet again — very slowly — until it gets [[https://en.wikipedia.org/wiki/Roche_limit so close]] that it's destroyed by Earth's gravity, becoming a ring system similar to Saturn's one but much smaller and denser. Note that those points are just academical since it's unlikely both the Earth and the Moon will survive the Sun's expansion into a red giant up to the Moon ending up destroyed that way due to interactions with the Sun's bloated atmosphere, and they'd take place in a far longer timescale.[[/note]]

* The ''Franchise/{{Tintin}}'' graphic novel ''Explorers on the Moon'' features a surprisingly realistic take on what travelling to the moon would be like, despite being written pre-Sputnik.

* In ''Film/TwoThousandOneASpaceOdyssey'' (written and premiered in the years prior to the Apollo landings) mankind has an established moonbase and space travel to the moon is a semi-mundane trip.

* ''Film/ATripToTheMoon'', the first movie to rely on special effects to tell the story of a trip, featured people getting shot to the Moon inside a giant cannon shell — which gave the Man in the Moon a black eye.

* Despite being made in 1929, German film ''Film/WomanInTheMoon'' (''Frau im Mond'') also was a serious attempt to depict such a landing, with some AcceptableBreaksFromReality due to it being a silent movie (e.g. having atmosphere on the Moon because the actors rely entirely on facial expressions).

* ''Series/DoctorWho'': The 1966 story [[Recap/DoctorWhoS4E6TheMoonbase "The Moonbase"]], set in 2070, has the Second Doctor visit a Moonbase that controls Earth's weather and stop the Cybermen (in their second appearance) taking over the Moonbase.

* ''Film/{{Apollo 13}}'', being based on the RealLife [[UsefulNotes/{{NASA}} Apollo moon mission]], has the Moon as the crew's ultimate (original) destination.
* ''Film/{{Apollo 18}}'' is a fictionalized account of a top secret final Moon landing, presented as a [[FoundFootageFilms Found Footage Film]].

** In 2007's [[Recap/DoctorWhoS29E1SmithAndJones "Smith and Jones"]], an entire hospital is teleported to the Moon by SpacePolice hunting an alien fugitive. The Doctor and Martha Jones meet and become a team in the confusion.
** 2014's [[Recap/DoctorWhoS34E7KillTheMoon "Kill the Moon"]] pulls ThatsNoMoon with ''the'' Moon, claiming that it's actually a giant egg that's about to hatch. Fortunately, the newborn creature lays a new Moon at the end.

* The pilot episode of ''Series/{{Salvage 1}}'' features Andy Griffith managing a mission to the moon in a homemade rocket. (They can get away with this because their NASA reject friend has concocted a rocket fuel hundreds of times more efficient than anything the space program has yet put into production.) His intent is to salvage all the "junk" the Apollo astronauts left lying around on the moon and sell it.
* ''Series/{{Space 1999}}'' takes place on Moonbase Alpha in the far distant future year of 1999. A nuclear explosion on the Moon's surface knocks it out of Earth orbit, sending it drifting through the galaxy rapidly enough to pass through a new star system every week.

* In ''TabletopGame/Warhammer40000'', during the Dark Age of Technology Luna was the site of advanced biomedical and anti-gravity research that made it the home base for a {{transhuman}}ist cult called the Selenar. In the 41st Millennium, it is the site of Holy Terra's main orbital defenses.

* The sixth mission of the Soviet campaign in the ''Yuri's Revenge'' expansion of ''VideoGame/RedAlert2'' has you chase the titular villain to the Moon so that he can't set up shop there. The gameplay becomes somewhat different in the mission compared to normal - there is no ore to mine, for instance, and you can produce high-flying Cosmonauts (basically normally-Allied Rocketeers specific to this mission) from Soviet barracks.
* At the beginning of ''VideoGame/StarControlII'' the quest you must do in order to have Commander Hayes and the Earth Starbase in your side is to deal with a base left in the Moon by the Ur-Quan Hierarchy. Once you go there, and especially when you find Fwiffo, you'll find Hayes' reports were ''very'' inaccurate.

* ''WesternAnimation/{{DuckTales|2017}}'' (2017–2021) has [[spoiler:Della Duck]] get stranded on the Moon for years before the events of the series, not knowing that [[spoiler:there's already a ''[[{{Lunarians}} full civilization of alien humanoids]]'' living there]].

-->Gekko: You think one day other people will walk on the moon too?
-->Catboy: Hate to break it to you Gekko, but 50 years ago, they did.

The Moon's surface is covered in craters, caused by comet and asteroid impacts in the ancient (and, occasionally, recent) past and that range in size from tiny craterlets seen with microscopes in the lunar rocks brought by space missions to large basins with concentric rings of mountains and sizes of up to 2,500 kilometres (the South Pole-Aitken Basin, one of the largest impact craters known in the Solar System). Each of those craters has a name, and most are named after scientists and philosophers. For instance, the great big crater with the huge white rays coming out of it in all directions is Tycho Crater, named after [[http://en.wikipedia.org/wiki/Tycho_Brahe Tycho Brahe]]. The moon's surface is also partially covered by "Seas" (''maria'' in [[GratuitousLatin Latin]]), [[TheArtifact a relic]] of the early days of telescopic observation when they were thought to be large masses of water, dark areas where ancient volcanoes spilled lava all over the place and that in most cases correspond to ''big'' craters similar to the already mentioned South Pole-Aitken Basin but smaller, excavated by [[ColonyDrop massive asteroid impacts]]. Like the craters, each Sea has a name, but unlike the craters the Sea names are derived from things that sailors might be concerned about — the Sea of Tranquility[[note]]Mare Tranquillitatis[[/note]], the Sea of Rains[[note]]Mare Imbrium[[/note]], the Sea of Fecundity[[note]]Mare Fecunditatis[[/note]], etc. Another interesting note is that the Moon ''does'' have a thin atmosphere, called an "exosphere". It's visible when there's a new moon and the Moon shows off a sulfurous "tail"[[note]][[http://time.com/4974580/nasa-moon-had-atmosphere-volcanoes/ Studies]] of the rocks brought back by the "Apollo" missions show the Moon to have had between 3 and 4 billion years ago an atmosphere twice as thick as Mars' current one produced by volcanism, that was stripped away by the solar wind[[/note]]

* ''WesternAnimation/{{DuckTales|2017}}'' (2017–2021) has [[spoiler:Della Duck]] get stranded on the Moon for years before the events of the series, not knowing that [[spoiler:there's already a ''full civilization of alien humanoids'' living there]].

* The ''Series/GetSmart'' episode "Pheasant Under Glass", which aired on September 26, 1969, has Max, 99 and the Chief holding a MissionBriefing while wearing spacesuits on the Moon. They lament that now that NASA has landed there as well, they'll have to find somewhere else to hold their secret briefings.

* Despite being made in 1929, German film ''Film/WomanInTheMoon'' (''Frau im Mond'') also was a serious attempt to depict such a landing, with some NecessaryWeasel due to it being a silent movie (e.g. having atmosphere on the Moon because the actors rely entirely on facial expressions).

[[AC: TabletopGames]]

* This is the main battle ground in ''VideoGame/AsurasWrath'' for the final fight between Asura and Augus, as well as the fights against [[spoiler: [[Franchise/StreetFighter Evil Ryu and Akuma[=/=]Oni.]]]]

* ''WesternAnimation/PJMasks'' has a special that takes place on the moon. Plus points to Catboy on one short that he mentioned about the Apollo 11: 2019-50= 1969. specifically the day of the Apollo mission.
--->Gekko: You think one day other people will walk on the moon too?
--->Catboy: Hate to break it to you Gekko. but 50 years ago.. They Did.

The Moon's surface is covered in craters, caused by comet and asteroid impacts in the ancient (and, occasionally, recent) past and that range in size from tiny craterlets seen with microscopes in the lunar rocks brought by space missions to large basins with concentric rings of mountains and sizes of up to 2,500 kilometres (the South Pole-Aitken Basin, one of the largest impact craters known in the Solar System). Each of those craters has a name, and most are named after scientists and philosophers. For instance, the great big crater with the huge white rays coming out of it in all directions is Tycho Crater, named after [[http://en.wikipedia.org/wiki/Tycho_Brahe Tycho Brahe]]. The moon's surface is also partially covered by "Seas" (''maria'' in [[GratuitousLatin Latin]]), dark areas where ancient volcanoes spilled lava all over the place and that in most cases correspond to ''big'' craters similar to the already mentioned South Pole-Aitken Basin but smaller, excavated by [[ColonyDrop massive asteroid impacts]]. Like the craters, each Sea has a name, but unlike the craters the Sea names are derived from things that sailors might be concerned about — the Sea of Tranquility[[note]]Mare Tranquillitatis[[/note]], the Sea of Rains[[note]]Mare Imbrium[[/note]], the Sea of Fecundity[[note]]Mare Fecunditatis[[/note]], etc. Another interesting note is that the Moon ''does'' have a thin atmosphere, called an "exosphere". It's visible when there's a new moon and the Moon shows off a sulfurous "tail"[[note]][[http://time.com/4974580/nasa-moon-had-atmosphere-volcanoes/ Studies]] of the rocks brought back by the "Apollo" missions show the Moon to have had between 3 and 4 billion years ago an atmosphere twice as thick as Mars' current one produced by volcanism, that was stripped away by the solar wind[[/note]]

The Moon's surface is covered in craters, caused by comet and asteroid impacts in the ancient (and, occasionally, recent) past and that range in size from tiny craterlets seen with microscopes in the lunar rocks brought by space missions to large basins with concentric rings of mountains with sizes of up to 2,500 kilometres (the South Pole-Aitken Basin). Each of those craters has a name, and most are named after scientists and philosophers. For instance, the great big crater with the huge white rays coming out of it in all directions is Tycho Crater, named after [[http://en.wikipedia.org/wiki/Tycho_Brahe Tycho Brahe]]. The moon's surface is also partially covered by "Seas" (''maria'' in [[GratuitousLatin Latin]]), dark areas where ancient volcanoes spilled lava all over the place and that in most cases correspond to ''big'' craters similar to the already mentioned South Pole-Aitken Basin, excavated by [[ColonyDrop massive asteroid impacts]]. Like the craters, each Sea has a name, but unlike the craters the Sea names are derived from things that sailors might be concerned about — the Sea of Tranquility[[note]]Mare Tranquillitatis[[/note]], the Sea of Rains[[note]]Mare Imbrium[[/note]], the Sea of Fecundity[[note]]Mare Fecunditatis[[/note]], etc. Another interesting note is that the Moon ''does'' have a thin atmosphere, called an "exosphere". It's visible when there's a new moon and the Moon shows off a sulfurous "tail"[[note]][[http://time.com/4974580/nasa-moon-had-atmosphere-volcanoes/ Studies]] of the rocks brought back by the "Apollo" missions show the Moon to have had between 3 and 4 billion years ago an atmosphere twice as thick as Mars' current one produced by volcanism, that was stripped away by the solar wind[[/note]]