I note the differences between the spin/revolution relationship of the moon’s
orbit around the earth, vs the spin/revolution relationship of the earth’s
orbit around the sun. The moon has an “intrinsic” spin, as if it were part
of a large rigid body revolving about the earth center. It thus spins once
per revolution. In contrast the earth has a daily spin – independent of its
yearly revolution.
Presumably the moon also once had an independent, “non-intrinsic” spin.
Received models assert that eons of tidal effects slowed its spin to its
present, synchronized, “intrinsic” value. Is there any reason to doubt that
the same effect will eventually occur with the earth’s motion – eventually
making the day equal to a year? If so, is there any way to estimate the
time rate of advance of this effect? Just curious.