Is space-time flat and if the answer is yes then how can objects orbit vertically and diagonally(since gravity is the warping of space-time)? Or does it exist from all sides?
What? I don't think Einstein talked about multiple universes to which you could travel if space-time is flat.....Space-time isn't flat,
If spacetime is absolutely flat, then if you were to set off in a rocket ship and travel in a single direction, you would eventually get to the universe that's just like the one you're in now, but where you got up an hour later this morning, or where Michael Jackson is still alive. And if you continued on this journey, eventually you would start getting to the other universes with basic physical laws, the other universes of the multiverse. What I belive is It's close to Flat, But not absolute flat
3D of Space Combine with 1D of Time to Form Malinowski space
Einstein in his book talked about this, Should read it..