Gravity isn't really a force but rather a distortion of spacetime, i.e.
a difference from simple flat geometry. It doesn't need to influence
spacetime because it is spacetime. We approximately treat it as a force
when we pretend that spacetime has a simple geometry.
As for the part about energy, you know that it the classical
Newtonian approximation, the field energy (potential energy) can be
converted to kinetic energy when things fall, and vice versa when
massive objects move apart. I'm not sure what the problem is.
MUWAHAHAHAHA!
Mike W.
(published on 10/22/2007)