Moon | Local Solar System Foundation

Moon

Earth's only natural satellite, the fifth-largest moon in the solar system.

NASA

Our only natural satellite, and the only other world where humans have walked.

The full Moon. — The full Moon, a mosaic from NASA's Lunar Reconnaissance Orbiter. Credit: NASA

The Moon is thought to have formed from debris after a Mars-sized body struck the young Earth. It always shows the same face to Earth because its rotation is locked to its orbit.

Its gravity raises the tides on Earth. Twelve astronauts walked on its surface during the Apollo missions between 1969 and 1972.

Data sources

Key facts
Diameter	3,475 km	[1]
Mass	7.346 × 10²² kg	[1]
Density	3.344 g/cm³	[1]
Surface gravity	1.62 m/s²	Derived from the dataset
Escape speed	2.38 km/s	Derived from the dataset
Rotation (sidereal)	27.3 days	[2]
Length of day	29.5 days	[3]
Orbital period	27.3 days	[4]
Axial tilt	6.68°	[2]
Mean temperature	-20°C	[3]
Distance from Earth	384,400 km	[4]
always shows the same face to Earth

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