Why we only ever see one side of the Moon
The Moon turns once for every trip around Earth, so one face always points our way. A slight wobble lets us peek at a bit more.
Look at the Moon on any clear night and you see the same face. The reason is that the Moon rotates once for every orbit it makes around Earth, so the same side always points toward us.
It was not always that way. Over a very long time, Earth’s tides slowed the Moon’s rotation until it came to rest with only one side facing us. The same pull that raises the ocean tides on Earth did that work on the Moon, which ties this story to our look at how the Moon moves the oceans.
The Moon still wobbles a little. The wobble is called libration, and it comes from the Moon’s slightly stretched orbit and from the roughly 5 degree tilt of that orbit. Over time those motions let observers on Earth see about 59 percent of the lunar surface.
That still leaves about 41 percent hidden. In April the four Artemis II astronauts flew around the far side, on the first crewed mission around the Moon in more than 50 years.