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It takes power to rotate in a gravitational field, because there are tides that pull both Earth & Moon into little ovoids and cause friction. After a long enough time any pair of orbiting bodies will become tidally locked. This is especially true when objects are relatively close compared to their diameter (moon is only 30 earths away), and the smaller object will lock much sooner, because it has much less angular momentum.

The moon used to be larger because it was closer, it every so slightly moves away from the earth. On a geological scale it will quite soon move far away that a total eclipse of the sun will no longer be possible.

It’s awesome now but in a few 100’s million of years it won’t be.

On a cosmological scale we’ll be eaten by our swelling sun in a blink of an eye too so there’s that...

I think the rotation thing is explained by tidal locking.