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The big facts page

123 Moon facts, all checked

Every fact on this site in one place, each linked to its NASA source. Our build checks each one against the source text; see the sources page. Things that can change carry the date we checked them.

Jump to: The basics | Size and distance | Orbit and spin | Phases | Tides and eclipses | Gravity, air and temperature | Inside the Moon | The surface | Missions and people | Myths

The basics

  1. 1 The Moon is Earth’s only natural satellite. NASA Science: Moon facts
  2. 2 In Latin, the Moon was called Luna. That’s where our word “lunar” comes from. NASA Science: Moon facts
  3. 3 Our Moon is just called “the Moon” because nobody knew other moons existed until Galileo Galilei discovered four moons orbiting Jupiter in 1610. NASA Science: Moon facts
  4. 4 The Moon isn’t a planet. It’s a natural satellite: a space object that orbits around something else. NASA Science: Top Moon questions
  5. 5 The Moon doesn’t make its own light. Moonlight is sunlight reflected off the Moon’s surface. NASA Science: Top Moon questions
  6. 6 The Moon has no moons of its own, and no rings. NASA Science: Moon facts
  7. 7 The Moon is the only place beyond Earth that people have visited, so far. NASA Science: Moon facts · checked 26 Oct 2026
  8. 8 Missions to the Moon have found no evidence that it has living things of its own. NASA Science: Moon facts

Size and distance

  1. 9 Put a green pea next to a US nickel (a 5-cent coin) and you have a good idea of the size of the Moon compared to Earth. NASA Science: Moon facts
  2. 10 With a radius of about 1,740 km, the Moon is less than a third of the width of Earth. NASA Science: Moon facts
  3. 11 The Moon’s mean radius is 1,737.4 km. Earth’s is 6,371.0 km. NASA NSSDC: Moon fact sheet
  4. 12 Earth is 3.7 times bigger across than the Moon. NASA Science: Earth and the Moon, by the numbers
  5. 13 The Moon has 0.0123 times Earth’s mass: Earth is about 80 times heavier. NASA NSSDC: Moon fact sheet
  6. 14 Earth has 80 times the Moon’s mass. NASA Science: Tides
  7. 15 The Moon is an average of 384,400 km from Earth: room for 30 Earth-sized planets in between. NASA Science: Moon facts
  8. 16 At its closest the Moon is 225,309 miles away, and at its farthest 251,903 miles. NASA Space Place: How far away is the Moon?
  9. 17 On NASA’s fact sheet, the Moon’s closest point (perigee) is 363,300 km and its farthest (apogee) 405,500 km. NASA NSSDC: Moon fact sheet
  10. 18 The Moon is slowly moving away from Earth, by about an inch (3.8 cm) a year. NASA Science: Moon facts
  11. 19 NASA’s fact sheet gives the Moon’s recession rate as 3.8 cm a year. NASA NSSDC: Moon fact sheet

Orbit and spin

  1. 20 The Moon spins once on its axis in the same time it takes to go once around Earth, so the same side always faces us. NASA Science: Moon facts
  2. 21 The Moon takes 27.3217 days to go once around Earth. NASA NSSDC: Moon fact sheet
  3. 22 From one new Moon to the next takes 29.53 days, a little longer, because Earth is moving around the Sun at the same time. NASA NSSDC: Moon fact sheet
  4. 23 Because Earth and the Moon are both moving around the Sun, it takes a little more than two extra days for sunlight to hit the Moon the same way again. NASA Science: Top Moon questions
  5. 24 The Moon travels around Earth at an average of 1.022 km per second. NASA NSSDC: Moon fact sheet
  6. 25 The Moon’s orbit is tilted about 5 degrees compared with Earth’s path around the Sun. NASA Science: Lunar eclipses
  7. 26 The Moon seems to nod and roll slightly over a month, so over time we can peek a little way round its edges. This is called libration. NASA Science: Moon phases
  8. 27 The Moon’s gravity keeps Earth from wobbling on its axis too much, which helps to keep our climate steady. NASA Science: Top Moon questions

Phases

  1. 28 The eight phases, in order, are: new Moon, waxing crescent, first quarter, waxing gibbous, full Moon, waning gibbous, third quarter and waning crescent. NASA Science: Moon phases
  2. 29 The Sun always lights up half of the Moon. Phases are how much of that lit half we can see from Earth. NASA Science: Moon phases
  3. 30 Phases are not caused by Earth’s shadow. The only time Earth’s shadow affects how the Moon looks is during a lunar eclipse. NASA Science: Top Moon questions
  4. 31 Everyone on Earth sees the same phase of the Moon. In the other hemisphere it just looks upside down. NASA Science: Top Moon questions
  5. 32 In the Northern Hemisphere a waxing crescent is lit on the right, and a waning crescent on the left. NASA Space Place: What are the Moon’s phases?
  6. 33 A full Moon rises around sunset and sets around sunrise. NASA Science: Moon phases
  7. 34 You can often see the Moon in the daytime. It’s up just as much in the day as at night. NASA Science: Top Moon questions
  8. 35 Earthshine is sunlight bouncing off Earth onto the dark part of the Moon. It makes the ‘unlit’ part of a crescent Moon glow faintly. NASA Science: Moon phases
  9. 36 NASA’s phase tables give the average time from new Moon to new Moon (for the year 2000) as 29.530588 days: 29 days, 12 hours, 44 minutes and 3 seconds. NASA GSFC: Phases of the Moon, 2001 to 2100 (F. Espenak)
  10. 37 Any one month from new Moon to new Moon can be anywhere from 29.26 to 29.80 days long, because of the Sun’s pull on the Moon’s oval orbit. NASA GSFC: Phases of the Moon, 2001 to 2100 (F. Espenak)
  11. 38 The Moon looks bigger near the horizon, but that’s an optical illusion. NASA Science: Top Moon questions
  12. 39 A ‘supermoon’ is a full Moon when the Moon is near its closest point to Earth. It isn’t an official astronomical term. NASA Science: Supermoons
  13. 40 At its closest, a full Moon can look up to 14% bigger and 30% brighter than the faintest full Moon of the year. NASA Science: Supermoons

Tides and eclipses

  1. 41 The Moon’s gravity is the main cause of Earth’s ocean tides. NASA Science: Tides
  2. 42 Most coasts get two high tides and two low tides a day. High tide to high tide takes a little over 12 hours. NASA Science: Tides
  3. 43 Spring tides (extra-high and extra-low) happen around new and full Moon, when the Sun, Moon and Earth line up. They’ve nothing to do with spring. NASA Science: Tides
  4. 44 Gentler neap tides happen around the first and last quarter Moons. NASA Science: Tides
  5. 45 The Sun has about 27 million times the Moon’s mass, but it’s about 390 times farther away, so it has a little less than half the Moon’s tide-raising power. NASA Science: Tides
  6. 46 Earth raises tides in the solid Moon too: about 10 to 15 cm. NASA Science: Tides
  7. 47 An eclipse of the Sun can happen only at new Moon, and an eclipse of the Moon only at full Moon. NASA GSFC: Phases of the Moon, 2001 to 2100 (F. Espenak)
  8. 48 NASA’s phase tables also mark each eclipse: T total, A annular, H hybrid and P partial for the Sun; t total, p partial and n penumbral for the Moon. NASA GSFC: Phases of the Moon, 2001 to 2100 (F. Espenak)
  9. 49 Every calendar year has at least two solar and two lunar eclipses, and at most 7 eclipses in all. NASA GSFC: Phases of the Moon, 2001 to 2100 (F. Espenak)
  10. 50 In a lunar eclipse the Moon can turn red, because the only sunlight reaching it has been filtered through Earth’s atmosphere. NASA Science: Lunar eclipses
  11. 51 There isn’t a solar eclipse at every new Moon: because the Moon’s orbit is tilted, it doesn’t usually pass directly between Earth and the Sun. NASA Science: Moon phases

Gravity, air and temperature

  1. 52 Gravity on the Moon is one-sixth of Earth’s, which is why astronauts seem to bounce. NASA Science: Moon facts
  2. 53 Surface gravity on the Moon is 1.62 m/s², compared with 9.80 m/s² on Earth: a ratio of 0.165. NASA NSSDC: Moon fact sheet
  3. 54 On the Moon you’d be able to jump about six times as high as on Earth, but you’d still come back down. NASA Science: Top Moon questions
  4. 55 To escape the Moon’s gravity you need 2.38 km per second. On Earth it’s 11.2 km per second. NASA NSSDC: Moon fact sheet
  5. 56 The Moon has only a very thin atmosphere called an exosphere. You couldn’t breathe it. NASA Science: Moon facts
  6. 57 In full Sun the Moon’s surface reaches about 127 °C, and in darkness it falls to about −173 °C. NASA Science: Moon facts
  7. 58 In deep, permanently shadowed craters near the poles, LRO has measured temperatures lower than −246 °C. NASA Science: Weather on the Moon
  8. 59 Today the Moon has only a very weak magnetic field. Earth’s is many thousands of times stronger. NASA Science: Moon facts
  9. 60 The Moon spins once on its axis every 655.720 hours: that’s about 27.3 Earth days. NASA NSSDC: Moon fact sheet

Inside the Moon

  1. 61 The Moon probably formed after a Mars-sized body crashed into the young Earth. Debris from both came together to make the Moon. NASA Science: Moon facts
  2. 62 That happened about 4.5 billion years ago, near the time the solar system formed. NASA Science: How the Moon formed
  3. 63 The object is often called Theia, after the Greek Titan who was mother of Selene, goddess of the Moon. NASA Science: How the Moon formed
  4. 64 The new Moon was molten. Within about 100 million years most of its ‘magma ocean’ had set solid. NASA Science: Moon facts
  5. 65 The Moon has a solid, iron-rich inner core 240 km in radius, inside a liquid iron shell 90 km thick. NASA Science: Moon facts
  6. 66 The crust is about 40 km thick on the near side and up to about 60 km on the far side. NASA Science: Moon facts
  7. 67 Long ago the Moon had active volcanoes. Today they’re all dormant and haven’t erupted for millions of years. NASA Science: Moon facts
  8. 68 The Moon has moonquakes. Seismometers left by Apollo astronauts recorded them. NASA Science: Moonquakes
  9. 69 Shallow moonquakes can reach 5.5 on the Richter scale and last more than 10 minutes. NASA Science: Moonquakes
  10. 70 The Moon’s density is 3.344 g/cm³, against 5.513 for Earth. NASA Science: Earth and the Moon, by the numbers

The surface

  1. 71 The Moon is covered in craters from asteroids, meteoroids and comets. There’s too little air to slow them down. NASA Science: Moon facts
  2. 72 Tycho Crater is more than 85 km wide. NASA Science: Moon facts
  3. 73 The dark patches are called maria, Latin for ‘seas’. They’re huge basins that filled with lava between 4.2 and 1.2 billion years ago. NASA Science: Moon facts
  4. 74 The light areas are called the highlands. NASA Science: Moon facts
  5. 75 Nearly the whole Moon is covered in charcoal-grey powdery dust and rocky rubble called regolith. NASA Science: Moon facts
  6. 76 The finest Moon dust is smaller than 10 to 20 microns, much thinner than a human hair. NASA Science: What the Moon is made of
  7. 77 On the old highlands, the regolith can be 20 metres deep. NASA Science: What the Moon is made of
  8. 78 Only about a tenth of the sunlight that hits the Moon bounces back. From Earth it looks bright, almost white, but much of its surface is really shades of dark grey. NASA Science: Moonlight
  9. 79 With no wind or air to wear them away, the Moon’s craters stay for a very long time. NASA Space Place: All about the Moon
  10. 80 Astronauts left things behind on the Moon: equipment, American flags and even a camera. NASA Science: Moon facts
  11. 81 The far side looks different from the near side. It has far fewer dark areas. NASA Space Place: All about the Moon
  12. 82 The first definitive discovery of water on the Moon was made in 2008 by India’s Chandrayaan-1 mission. NASA Science: Moon facts
  13. 83 There is water ice in permanently shadowed craters at the Moon’s poles, where sunlight never reaches. NASA Science: Moon facts
  14. 84 In 2009 NASA’s LCROSS spacecraft fired a projectile into a crater, then flew through the debris and found grains of water ice in it. NASA Science: Water and ices on the Moon
  15. 85 In October 2020 NASA’s SOFIA observatory confirmed water on the sunlit surface of the Moon for the first time, in Clavius Crater. NASA Science: Moon facts
  16. 86 LRO has photographed the Apollo 11 landing site: the descent stage left behind is visible, and so are the trails of the astronauts’ footprints. NASA Science: Apollo 11 landing site, seen by LRO

Missions and people

  1. 87 More than 105 robotic spacecraft have been launched to explore the Moon. NASA Science: Moon facts · checked 26 Oct 2026
  2. 88 Nobody saw the far side of the Moon until a Soviet spacecraft flew past in 1959. NASA Science: Moon facts
  3. 89 Luna 2 (USSR) was the first spacecraft to hit the Moon, on 13 September 1959. NASA Science: Moon missions
  4. 90 Luna 3 (USSR) took the first pictures of the far side in October 1959. NASA Science: Moon missions
  5. 91 Luna 9 (USSR) made the first soft landing and sent the first picture from the surface, in February 1966. NASA Science: Moon missions
  6. 92 Apollo 8’s crew, Frank Borman, Jim Lovell and Bill Anders, were the first people to orbit the Moon, on Christmas Eve 1968. NASA: Apollo 8
  7. 93 Bill Anders took the ‘Earthrise’ photo from lunar orbit on 24 December 1968. NASA: Apollo 8
  8. 94 Apollo 11 launched on 16 July 1969 with Neil Armstrong, Michael Collins and Buzz Aldrin. NASA: Apollo 11 mission overview
  9. 95 On 20 July 1969 Neil Armstrong became the first person to step onto the Moon: “That’s one small step for a man, one giant leap for mankind.” NASA: July 20, 1969, One Giant Leap for Mankind
  10. 96 An estimated 650 million people watched on television. NASA: Apollo 11 mission overview
  11. 97 Landing the lunar module Eagle in the Sea of Tranquility, Armstrong flew it by hand past an area littered with boulders. NASA: July 20, 1969, One Giant Leap for Mankind
  12. 98 When Eagle landed, only 30 seconds of fuel remained. NASA: July 20, 1969, One Giant Leap for Mankind
  13. 99 Armstrong radioed: “Houston, Tranquility Base here. The Eagle has landed.” NASA: July 20, 1969, One Giant Leap for Mankind
  14. 100 Michael Collins stayed in lunar orbit in the command module, Columbia. NASA: Apollo 11 mission overview
  15. 101 Armstrong and Aldrin spent 21 hours, 36 minutes on the Moon’s surface. NASA: Apollo 11 mission overview
  16. 102 Aldrin described the surface as “magnificent desolation”. NASA: July 20, 1969, One Giant Leap for Mankind
  17. 103 Twelve people have walked on the Moon, starting with Neil Armstrong and Buzz Aldrin. NASA Science: Who has walked on the Moon?
  18. 104 24 American astronauts travelled from Earth to the Moon between 1968 and 1972. NASA Science: Who has walked on the Moon?
  19. 105 Three astronauts went to the Moon twice: James Lovell, John Young and Gene Cernan. NASA Science: Who has walked on the Moon?
  20. 106 Apollo astronauts brought back 382 kg of Moon rocks and soil. Scientists are still studying them. NASA Science: Moon facts
  21. 107 Apollo 13 couldn’t land, but its crew returned safely to Earth. NASA Science: Moon missions
  22. 108 Apollo 15, in 1971, was the fourth Moon landing mission and the first to use a lunar rover. NASA: Apollo 15
  23. 109 Lunokhod 1 (USSR, 1970) was the first robotic rover to explore another world. NASA Science: Moon missions
  24. 110 Apollo 17, in December 1972, was the last Apollo Moon landing and the first with a scientist on board, geologist Harrison Schmitt. NASA Science: Moon missions
  25. 111 Gene Cernan, Apollo 17’s commander, was the last person to leave footprints on the Moon. NASA: Apollo 17
  26. 112 China’s Chang’e 4 and its rover Yutu 2 made the first landing on the far side, in January 2019. NASA Science: Moon missions
  27. 113 India’s Chandrayaan-3 was the first spacecraft to soft-land near the lunar south pole, in August 2023. NASA Science: Moon missions
  28. 114 China’s Chang’e 6 brought back the first samples from the far side, in 2024. NASA Science: Moon missions
  29. 115 NASA’s Lunar Reconnaissance Orbiter has been studying the Moon up close since 2009, the longest-lived lunar orbiting mission ever. NASA Science: Lunar Reconnaissance Orbiter · checked 26 Oct 2026
  30. 116 Artemis I (November 2022) was the first flight test of NASA’s SLS rocket and Orion capsule, with no crew. NASA Science: Moon missions
  31. 117 Artemis II launched on 1 April 2026 and splashed down on 10 April 2026, after 9 days, 1 hour and 32 minutes. NASA: Artemis II
  32. 118 Its crew, NASA astronauts Reid Wiseman, Victor Glover and Christina Koch and Canadian astronaut Jeremy Hansen, travelled around the Moon. NASA Science: Who has walked on the Moon?
  33. 119 Artemis II carried its four astronauts around the far side of the Moon, flying past on 6 April 2026. NASA Science: Moon missions

Myths

  1. 120 There is no permanent dark side of the Moon. The far side gets as much sunlight as the near side. NASA Science: Top Moon questions
  2. 121 At new Moon, it’s daytime on the far side. NASA Science: Moon facts
  3. 122 The Moon has a solid, rocky surface, and inside it has a core, mantle and crust. NASA Science: Moon facts
  4. 123 The Moon’s ‘seas’ aren’t water. They’re old lava. NASA Space Place: All about the Moon