How come the moon spins at the same speed it orbits around earth?

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It takes 27 days for the moon to spin completely and the exact same time for it to orbit around earth, thus creating a situation where we can always only see the same side of the moon.

Surely, this synchronization is not a coincidence but how exactly did we reach that point? I read some articles but found them vague.

In: Planetary Science

9 Answers

Anonymous 0 Comments

It’s because of tidal locking. The moon is close enough to the Earth that the Earth’s gravity makes the moon slightly oblong. The “bulge” of the moon that faces the Earth is pulled more strongly to the Earth than the rear, and more strongly than the sides would be if it was turned 90 degrees. This means if the “bulge” of the moon ever began to turn away from the Earth, the Earth would try to pull it back. Therefore, this bulge will try to always face the Earth, and it’s this bulge that we see from the Earth’s surface.

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