A question on how Einstein declared gravity and acceleration to be the same?

Question

I'm reading The Fabric of the Cosmos by Brian Greene, and it was going pretty good until the point where the author explained how Einstein came up with the idea of gravity being warps in space. Apparently, it was the fact that acceleration and gravity are the same, and since acceleration causes observers to cut the "loaf of spacetime" differently, and that their slices are "curved" (I don't understand this either) but fit together, and that "an accelerated observer carves spacial slices that are warped", so gravity is nothing but curves and warps in spacetime.

I understand how observers at different speeds cut spacetime differently, but I don't get the whole idea of it "curving" and how Einstein make the leap from that too warps in spacetime. I'm a little confused on this part, and it would be so great if someone could explain this to me. I really want to understand this! That you so much to anyone who takes the time to answer!

Answer 1

Einstein concluded that gravity is indisinguishable from acceleration from thought experiments. For instance, were it not true you could convert mass to energy at the bottom of a tower, shine the energy as light to the top and convert it back. The mass would now have more gravitational potential energy at the bottom of the tower, and preseto you have perpetual motion/infinite energy and the laws of physics come to an end. Hence gravity must act on everything in the same way, regardless of mass, and hence there is no way to distinguish it from acceleration.

And the outcome of this principle of equivalance is that spacetime is not flat, but curves. That takes more explanation than there is room for here.

Answer 2

wierd.

Answer 3

i wasn't really paying attention but the hole loaf and curv type of thing is talking about a loaf of bread is curved or was back then... no clue about spacetime stuff so can't really say any more.