Moon rock that was returned to Earth by the Apollo astronauts was determined to be as old as 4.4 billion years. Astronomers conclude that the Earth's Moon formed from a giant impact of a Venus sized objects blasting material from Earth's outer layers. This concept is known as the Lunar Impact Theory.

The Moon is a natural satellite of Earth and is tidally locked to the Earth. This causes the rotation rate of the Moon on its axis to equal the revolution rate around the Earth. This is the reason the same side of the Moon always faces toward the Earth. The Moon has no atmosphere or magnetic field and thus it is weathered slowly and continuously by impacts from micrometeors and particle from the Sun known as the solar wind.

The Moon's surface temperature varies between (100 K to 400 K or -173°C and 127°C) and is approximately as far as 406,000 km or 253,750 miles from Earth at its greatest separation from Earth.