I explained to someone I know about General Relativity (as much as I know).
He said that he didn't see how it could be correct.
How is 4-dimensional space-time space different to 3-dimensional space? he doesn't agree that as that because the 4-dimensional space-time is only different to 3-dimensions because of the added time dimension. he doesn't think that the added dimension of time would change the space of the system (so 3-dimensional space therefore wouldn't be different to 4-dimensional) because they both still have 3 spacial dimensions, just space-time has an added dimension of time.
I said there will be an explanation to how an added dimension of time would change the spacial structure. is there?