The Moon rotates at the same speed it orbits Earth, so we only ever see one side of it.

Earth's gravity pulls on the Moon and has slowed its rotation over billions of years. This process is called tidal locking. Earth's pull created a slight bulge in the Moon's shape, which acted like a brake until the Moon's spin matched its orbit speed.The side we never see from Earth is called the far side. Humans did not see it until the Soviet Luna 3 spacecraft took photos of it in 1959. Even though we usually see the same side, the Moon has a slight wobble called libration. This wobble lets us see about 59% of the Moon's surface over time instead of just 50%.The Moon is currently moving away from Earth at a rate of 3.8 centimeters per year. Scientists measure this distance using lasers and reflectors left on the Moon by Apollo astronauts. The Moon also lacks an atmosphere, so there is no wind or rain to wash away footprints or craters. This means the marks left by astronauts in the 1960s and 1970s are still there today.