Originally Posted By: Bill S.
Originally Posted By: redewenur
Alternatively, Bill, there's General Relativity explanation, according to which no acceleration is being applied to the Moon. Instead, the Moon follows a geodesic through the curvature of spacetime caused by the mass of Earth.


This does not answer the question. The question is "how does the presence of the Earth hold the geodesic in shape without expending energy?"

I can't answer the question adequately, Bill, since it appears that to do so would require a working knowledge of tensor mathematics and Einstein's field equations. All I can tell you is that, as I understand it, the mass of the Earth defines the geometry of local spacetime. That's why no energy is expended.

"Time is what prevents everything from happening at once" - John Wheeler