The moon is round, right?
Answer
This has evolved over time, as a result of the tidal action of the Earth on the Moon, which is deformed by the Earth’s gravity. The moon is not really round, but slightly stretched in the direction of the axis that connects the earth and the moon, and the thickness of the crust is thinner on the side of the earth. The result is a coupling between the rotation period and the revolution period, a so-called spin-orbit resonance with (in this case) ratio 1/1.
This phenomenon has already been discussed on this website. See for example on this website: question 28081
Or take a look at the english wikipedia under the title “tidal locking”.

Answered by
prof.dr. Paul Hellings
Department of Mathematics, Fac. IIW, KU Leuven

Old Market 13 3000 Leuven
https://www.kuleuven.be/
.