The Moon's surface

Key facts

Diameter

≈ 3,474 kmAbout 27% of Earth's

Surface gravity

1.62 m/s²About one-sixth of Earth's

Average distance

≈ 384,400 km

Lunar day

≈ 29.5 Earth daysAbout two weeks of daylight, then two weeks of night

Surface temperature

≈ 120°C to −130°CDay and night near the equator

Coldest measured

Below −240°CIn permanently shadowed polar craters

Atmosphere

Almost noneAn extremely thin exosphere

Largest impact basin

South Pole–AitkenAbout 2,500 km across

Crewed landings

6Apollo 11, 12, 14, 15, 16 and 17, 1969–1972

Apollo samples

≈ 382 kgRock and soil returned to Earth

Regolith: the lunar soil

Almost the whole Moon is blanketed in regolith, a layer of loose dust and broken rock made by billions of years of meteorite impacts grinding up the bedrock. It is typically a few metres thick on the dark plains and thicker, perhaps 10–15 m, in the older highlands. The fine portion is often called lunar soil, though it contains no living matter.

Lunar dust is very unlike dust on Earth. With no wind or water to round them off, the grains are sharp and jagged, and many are tiny glass beads formed in impacts. The dust clings to everything, partly through static charge. Apollo astronauts found it scratched visors, clogged seals and smelled, they said, like spent gunpowder once brought into the cabin. Managing dust is a major engineering challenge for future missions.

Craters, maria and highlands

Craters are the Moon's defining feature. They range from microscopic pits to huge basins, and many larger ones have central peaks, terraced walls and bright rays of ejecta. The crater Tycho, about 85 km across, sprays rays across much of the near side, and the South Pole–Aitken basin, roughly 2,500 km wide, is one of the largest known impact structures in the Solar System.

To the naked eye, the Moon has two kinds of terrain. The bright highlands are old, heavily cratered crust made largely of a pale rock called anorthosite. The dark maria, Latin for 'seas', are vast plains of basalt lava that flooded giant impact basins more than three billion years ago. Maria cover about 16% of the Moon, almost all on the side facing Earth, which is why the near and far sides look so different.

The black sky and Earth above

With almost no atmosphere to scatter sunlight, the lunar sky is black even when the Sun is up. Shadows are sharp and very dark, and distant objects look as crisp as near ones, which makes distances hard to judge. Stars are there, but the glare of the sunlit ground makes them hard to see or photograph, which is why they rarely appear in Apollo surface pictures.

Because the Moon always keeps the same face towards Earth, an observer on the near side sees Earth hang in roughly the same place in the sky, rocking only slightly. Earth looks about four times wider than the full Moon does from Earth and passes through phases, from new to full, opposite to the Moon's phases seen from home. From the far side, Earth is never visible at all.

Temperature swings and polar ice

A lunar day lasts about 29.5 Earth days, so most places get around two weeks of sunshine followed by two weeks of night. With no air to hold heat, the surface near the equator can reach about 120°C in the day and fall to about −130°C at night. Equipment and astronauts must cope with both extremes.

Near the poles, the Sun always skims the horizon, and the floors of some deep craters have not seen direct sunlight for billions of years. NASA's Lunar Reconnaissance Orbiter has measured temperatures there below −240°C, among the coldest anywhere in the Solar System. In 2009 the LCROSS impactor confirmed water ice in one such crater, making the south polar region a prime target for future exploration.

The Apollo landing sites

Apollo 11 landed on the Sea of Tranquillity on 20 July 1969, and Neil Armstrong and Buzz Aldrin spent about two and a half hours outside. Apollo 12 touched down in the Ocean of Storms beside the earlier Surveyor 3 probe. Apollo 13 had to abort its landing after an oxygen tank exploded, and Apollo 14 landed in the Fra Mauro highlands instead.

The last three missions carried a lunar rover. Apollo 15 explored Hadley Rille at the foot of the Apennine mountains, Apollo 16 landed in the Descartes highlands, and Apollo 17, in December 1972, explored the Taurus–Littrow valley, where geologist Harrison Schmitt became the only professional scientist to walk on the Moon. The Lunar Reconnaissance Orbiter has since photographed all six sites, showing descent stages, rover tracks and footpaths.

Artemis and the return to the Moon

NASA's Artemis programme aims to return astronauts to the Moon and build a longer-term presence, starting near the south pole, where water ice could provide drinking water, oxygen and rocket fuel. Artemis I flew an uncrewed Orion capsule around the Moon in late 2022, and Artemis II carried four astronauts on a crewed flight around the Moon in 2026, the first people to travel there since 1972.

The first Artemis landing will use a commercially built lander. Its timing and mission plan have changed several times, so it is best to check NASA for the latest schedule. Other nations are active too: China's Chang'e missions have landed on the far side and returned samples from it, India's Chandrayaan-3 landed near the south pole in 2023, and China plans crewed landings around 2030.

Surprising facts about the Moon's surface

• Astronaut footprints could last for millions of years, because there is no wind or rain to erase them, only a slow rain of micrometeorites.
• The Moon is drifting away from Earth by about 3.8 cm a year, measured with lasers bounced off reflectors left by Apollo astronauts.
• Moonquakes happen: Apollo seismometers recorded thousands, some lasting far longer than typical earthquakes because the dry rock rings like a bell.
• Apollo astronauts said lunar dust smelled like spent gunpowder once they brought it back into the lander.
• Because the Moon is smaller than Earth, its horizon is closer; for a standing person it is only about 2.4 km away on flat ground.
• The Moon's surface is actually quite dark, reflecting only about as much light as worn tarmac; it looks bright only against the black sky.

Frequently asked questions

What is the Moon's surface made of?

A layer of dust and broken rock called regolith covers bedrock of two main types: pale anorthosite in the highlands and dark basalt lava in the maria.

Why is the sky black on the Moon?

The Moon has almost no atmosphere, so there is nothing to scatter sunlight across the sky. The sky stays black even in full daylight.

How hot and cold does the Moon get?

Near the equator the surface reaches about 120°C during the day and falls to about −130°C at night. Permanently shadowed polar craters can be colder than −240°C.

Where did the Apollo missions land?

At six sites on the near side: the Sea of Tranquillity (Apollo 11), Ocean of Storms (12), Fra Mauro (14), Hadley–Apennine (15), Descartes highlands (16) and Taurus–Littrow (17).

Can I walk on the Moon in the app?

Yes. You can land on the Moon and explore its craters, dust and black sky in interactive 3D.

Keep exploring

• Land in the 3D moon landscape and walk around
• The Moon: full guide to Earth's satellite
• Spacecraft exploring the Solar System
• Jungle: layered rainforest, a muddy river and drifting spores
• Desert: wind-carved dunes with sharp crests and long shadows
• Glacier: a river of blue ice between granite peaks
• Gas giant clouds: drifting cloud decks, lightning and a giant storm

The landscapes in Ember’s Universe are procedural 3D scenes modelled on real places. The landforms, plants and light follow the real thing, but the details are generated, not mapped.

Sources

• NASA — Earth's Moon
• NASA — Moon facts
• NASA — Lunar Reconnaissance Orbiter
• NASA — The Apollo program
• NASA — Artemis