The Retreating Moon
A very interesting fact to consider here is that what has always been considered the capture process may very well not be truly capture after all. The current picture of the Moon’s orbit indicates that it may eventually retreat to a point at which it will leave the Earth’s orbit.
This is because the energy of the ocean tides slows the Earth’s spin rate. The law of physics, which says that angular momentum must be conserved, implies that if the Earth slows, then the Moon must retreat. This fact also “opens the window a little wider” by requiring less energy to be dissipated than would be required for total or “complete capture.” It has been proven that both are happening: the Earth is slowing and the Moon is in fact retreating.. Thus it is only a temporary condition in which the Moon and Earth reside. The mere fact that the Moon is in such a temporary state substantiates the capture theory in a way. If it is understood that the Moon is going to leave, then why do we think that it could not have arrived?
To complicate the situation even further, consider the subject of tidal dissipation of energy. Though on a purely theoretical basis, the capture event is only temporary, it may actually be the case that the effect of the tidal energy dissipation may in the future slow down the Moon’s retreat. Before it can actually escape it could slow, stop, and begin to re-approach and eventually crash into the Earth. The balance of dynamic energy between these two passing astronomical bodies is incredibly delicate. This dance is so tightly orchestrated that it is not known which will actually occur. It is a matter of study and really depends on assumption, a tug of war between the pull of the Sun and the tidal loss of energy to the liquid surface of the Earth (the oceans) and solid body dissipation.
The Moon at this time has three potential futures. One is that it continues to retreat until it escapes back into a sun-centered orbit. Another is that it retreats and is slowed until it stops and begins to circle back inward towards the Earth with it ultimately crashing into the Earth. The third and possibly least likely is that through an extremely precise set of circumstances it retreats to the perfect distance, stops and is actually captured into a stable orbit. If this were to happen, the Moon would have the attributes of a typical regular satellite like many of the other satellites of the solar system.
Ironically, though this is termed a capture model, it could ultimately turn into a collision model. But, it is probably described best as a temporary capture model.