Moon
Earth's only natural satellite
About Moon
The Moon is Earth's only permanent natural satellite. It is the fifth-largest moon in the Solar System and influences Earth's tides, stabilizes its rotation, and has been a target for human exploration.
Scientific Facts
The Moon has a diameter of 3,474 km. Its surface gravity is 16.6% of Earth's. It moves away from Earth at 3.8 cm per year. It orbits Earth every 27.3 days.
Interesting Facts
The Moon was likely formed by a Mars-sized body colliding with Earth. The Moon has no atmosphere. Footprints on the Moon will last millions of years.
Fun Facts
The Moon is the only celestial body humans have walked on. The dark side of the Moon is not actually dark – it gets sunlight too.
Discovery
Known since prehistoric times. First mapped by Galileo in 1609. First visited by humans in 1969 (Apollo 11).