as a result of the presence of mass.

"So, was Einstein's thought experiment valid or not? When I read about Einstein's thought experiment, I couldn't help wondering "if there's no gravity, what the heck is pushing the elevator?" "

the presence of mass curves space-time such that the two or more massive objects come towards one another. the mass literally has no where else to go.

the interesting question is what is it about mass that makes space-time curve in such a way as to bring two or more mass's towards one another?

i think Einstein's equavalency principle was correct, if not then it is at least one of the most esoterically pleasing scientific principles i've seen.

regards, tim