Moon
The Moon is Earth's only natural satellite and the only world beyond Earth where humans have walked. Ancient impacts left dense craters; dark maria were paved by lava, and permanently shadowed polar regions preserve water ice.
Moon Science file
A tidally locked, · gray neighbor
Basic properties
- Distance from the Sun
- 384,400 km
- Equatorial diameter
- 3,474.8 km
- Orbital period
- 27.3 Earth days
- Rotation period
- 27.3 Earth days
- Surface gravity
- 16.5% of Earth's
- Typical temperature
- About −173 to 127°C
- Atmosphere
- Extremely thin exosphere
- Moon system
- No moons of its own
Highlights
Always showing Earth the same face
The Moon takes almost exactly as long to rotate once as it does to orbit Earth, so we continually see the same hemisphere.
The far side is not always dark
It experiences day and night like the near side; “dark side” is a historical name, not a place sunlight never reaches.
Ice in polar shadows
The floors of some polar craters never see sunlight, and exploration missions have confirmed water ice there.