The Moon Is Slowly Moving Away

The Moon is not fixed in place. It is slowly drifting away from Earth.

Measurements from laser reflectors left by Apollo astronauts show the Moon recedes by roughly 3.8 centimeters each year. The effect is tied to tidal interactions between Earth and the Moon.

That tiny yearly change adds up across deep time, reshaping eclipses, tides, and the long story of the Earth-Moon system.