| I think it's to do with the centre points of gravity. Definatelly it is to do with acceleration, mass and distance.
But there is something I know, and I didn't kno wuntil very little time ago, and it is that the earth and the moon also move around a point between the two, not in the middle, but nearer to the earth, because it's to do with the mass. So actually it's not exactly how the diagram says, there is another rotation, done by the two, around this point which is probably in earth, around where planes fly, I estimate, due to the masses. |