Moon
The Moon
Natural satellite of Earth
Earth's constant companion
The fifth-largest moon in the solar system, likely formed from debris after a Mars-sized body struck the early Earth. Tidal locking keeps the same face pointed toward us.
In your sky
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Key facts
Distance
~384,400 km from Earth (mean)
Diameter
3,474 km
Orbital period
27.3 days (sidereal)
Phase cycle
29.5 days
Gravity
16.5% of Earth's
Orbits
Earth
Did you know
- It is drifting away from Earth by about 3.8 cm per year.
- Twelve astronauts walked on its surface between 1969 and 1972.
- Its gravity drives most of Earth's ocean tides.
