Earth-Moon System
The Earth-Moon System consists of the planet Earth and its only natural satellite, the Moon. The Moon orbits Earth at an average distance of about 238,855 miles (384,400 kilometers) and takes approximately 27.3 days to complete one orbit. This gravitational relationship affects various phenomena, including ocean tides on Earth.
The Moon is about one-quarter the size of Earth and has a significant impact on our planet's rotation and axial tilt. It is believed to have formed around 4.5 billion years ago, likely from debris resulting from a collision between Earth and a Mars-sized body.