The Moon is the only naturally occurring satellite of Earth. The Moon orbits the Earth at a distance of 238,855 miles and has a mass of 7.35e33kg. The Moon is the second brightest object after the Sun. It orbits the Earth once every 29.5 days. The Moon was visited by the Soviet spacecraft Luna 2 in 1959. It is also the only planet ever visited by humans. The gravity of the Moon causes the tides. It also causes the Earth's rotation to slow down by 1.5ms per 100 years. The Moon's orbit get higher by 3.8cm per year.
