Jason Bradwell's 365/366 Photo a Day Blog

The average distance from the Earth to the Moon is 238,856 miles, about thirty times the diameter of the Earth. The Moon's diameter is 2,158 miles, a little more than a quarter that of the Earth. This means that the Moon's volume is about 2 percent that of Earth and the pull of gravity at its surface about 17 percent that of the Earth. The Moon makes a complete orbit around the Earth every 27.3 days, and the periodic variations in the geometry of the Earth–Moon–Sun system are responsible for the lunar phases that repeat every 29.5 days.

The Moon is the only celestial body to which humans have travelled and upon which humans have landed. The first spacecraft to perform a successful lunar soft landing was Luna 9, and the first unmanned vehicle to orbit the Moon was Luna 10, both in 1966. The United States Apollo program achieved the only manned missions to date, resulting in six landings between 1969 and 1972. The first man to set foot on the moon was Neil Armstrong on July 20, 1969. Human exploration of the Moon ceased with the conclusion of the Apollo program, although several countries have announced plans to send people or robotic spacecraft to the Moon.