Originally Posted By: Bill S.
Originally Posted By: abacus9900
gravity is defined as being the curvature of space due to the presence of matter, or mass.


This makes sense, but causing and maintaining this curvature of space (or spacetime)must require energy. Did Einstein, or anyone else for that matter, identify the source of this energy?

Einstein, E=mc^2 (mass–energy equivalence, i.e.,the mass of a body is a measure of its energy content)

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