The Moon is Earth's only natural satellite. With an equatorial diameter of 3,476 km, it is the fifth largest satellite in the solar system and is located at an average distance of 238,855 miles (384,400 km) from Earth. Although the Moon is considered to have no atmosphere, there are some gases such as Argon, Helium and Hydrogen. Gravity is 0.166 of Earth's gravity (if you weigh 45 kilograms on Earth, you weigh 7.5 kilograms on the Moon).