To describe phenomena on the scale of atoms, we use the second great theory: quantum mechanics, which differs from general relativity in basically everything. It uses flat space-time and a completely different mathematical apparatus
It’s weird to me, that the common method of attempting to describe a four dimensional thing is to immediately reduce the three dimensional thing to two dimensions…
The word “curved” is problematic for the concept of space-time because it invokes one or two dimensional thought. Space-time is a four dimensional model.
The best description of the effect of gravity on space-time on my opinion is actually a joke… Gravity sucks :)
Curvature is well defined for manifolds with any number of dimensions. “Flat” in this context means “zero curvature”, not “two dimensional”.
Can I get an ELI5, please? I understand all of those words, but not the concepts behind them in this context…
The definition of a right angle depends on the number of dimensions. Perpendicularity and parallelism are different in higher dimensions. Space is hard.
There is no such thing as a four dimensional “spacetime”. That is a abstract math only concept, nothing to do with reality. Time is not a thing, nor is it a dimension. Reality is not curved or flat. That is abstract geometry that they are talking about, not reality. Only 3 abstract dimensions are required to locate anything in reality. Time is just when you want to examine these three dimensions.
