The Moon is Earth's only natural satellite. It is the fifth-largest
natural satellite in the Solar System. The Moon is almost as large as
Earth's nearest competitor, Mars, which has two small natural
satellites.
The surface of the Moon is primarily composed of basaltic rock. It has
no atmosphere, and its surface features are primarily the result of
impacts from meteoroids and other celestial objects. The Moon's
surface is also characterized by a number of impact craters, which are
remnants of these impacts.
