The Science Shtick
 
Orbital Degradation

Related to the torque created by tidal forces acting upon a spinning object is a phenomenon called orbital degradation.

As a mass of radius R spins and carries its tidal bulge out of alignment with its satellite of mass M, the two bulges both act to attract the mass M in different directions. However, the more distant bulge, has a weaker affect and so the direction of mass M's acceleration vector is diverted towards the closer bulge and away from the center of mass. More to the point, this diversion of the acceleration adds a tangential component to the vector, which can either contribute to or take away from mass M's orbital velocity.

This change in orbital velocity will cause the satellite's orbit to either tighten down, moving in towards the mass of radius R (corresponding to a decreasing orbital velocity) or loosen up moving out away from the mass (corresponding to an increasing orbital velocity vector).

As an example, the Earth, which rotates faster than the moon, causes the moon to accelerate in its orbit and gain a greater average distance, moving further out at a rate of about 3 to 4 centimeters per year. (Modern Astrophysics, p. 764)

In contrast, if the moon revolved around the Earth faster than the Earth revolved upon its axis, then the affect of orbital degradation would be to cause the moon to slow down and move in closer to the Earth.

Similarly, if the moon revolved around the Earth opposite the Earth's rotation upon its axis, (termed "retrograde" motion) then the effect of orbital degradation would be to cause the moon to slow down and eventually stop, that is, if it weren't for another interesting phenomenon that would occur first.