Ocean tides are considered to be mostly caused by the force of gravity from the Moon. Tides are presumably caused by the difference of the force applied on the "front" and on the "back"of the Earth. Meaning, gravity from the Moon cause Earth's shape to become elliptical in the plane of the moon, and these tides are more apparent on the oceans than on land simply because land is rigid while water ain't. Now. The moon is in tidal lock wrt Earth, so the forces from the Earth should create a very big tide on the Moon: there should be a big bulge (or a small one, doesn't matter) both on the dark side and on the bright side of the Moon, and the poles should be flattened, especially because the tides are locked in basically the same places, so there's no way for the forces from the Earth to be distributed over the surface (which would only minimize the tidal effects – there still should be flattening at the poles). So how come we actually see a negative tide on the moon? Look at this image to what I mean by negative tide: http://ase.tufts.edu/cosmos/pictures/Explore_figs_8/Chapter5/Fig 5_22copy.jpg Instead of a bulge on the bright side, we see a sort of obliteration of the crust, revealing the so called "mare". Ths is clear from the words "thin crust" and "thick crust" front and back. Isn't this evidence against tidal theory? Or is there a satisfactory explanation?