Our Moon, Luna, is the only natural satellite of Earth. It orbits 384,400 kilometers from Earth. It has a diameter of 3476 kilometers, and it's mass is 7.35e22. The Moon was named Luna by the Greeks, but it was called other names by other cultures (the Greeks called it Selene and Artemis).

The Moon has been known since prehistoric times. It is the second brightest object in the sky, after the sun. As the Moon orbits around the Earth, the angle between the Earth, Sun, and Moon changes, creating the Moon's phases.

The Moon was first visited by the USSR spacecraft Luna 2 in 1959. It is the only extraterrestrial body to have been visited by humans. The first moon landing was on July 20, 1969, and the last visit was in December 1972. The surface of the moon has been mapped twice, once by Clementine and then by the Lunar Prospector.

The gravitational pull between the Earth and Moon has many effects. One of the effects is the tides. The Dark side of the moon (the side that never faces the Earth) wasn't seen until it was photographed by the USSR spacecraft Luna 3 in 1959.

The moon has no atmosphere. However, data from Clementine showed that there may be some water ice in deep craters on the Moon's south side. It has now been proven (by the Lunar Prospector) that there is water ice at both the north and south poles on the Moon. This could make staying on the moon (colonies) much easier.
There are two types of terrain on the Moon's surface; The old and craterd highlands and the younger and smoother maria. Most of the craters on the near side of the moon are named after famous scientists. Features on the far side are named after more recent scientists. Most of the rocks on the moon's surface seem to be between 4.6 and 3 billion years old. Scientists now believe that the moon was formed when a very large object collided with the Earth and the Moon formed from the debris.
The Moon has no global magnetic field. However, some of the rocks on the Moon have slight magnetism, evidence that the Moon may have had a magnetic field in it's early history.

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