>If there were a big-bang, and we were at the edge, different parts would accelerate away from us at different speeds
You're operating on a very outdated understanding of what the big bang was - for half a century now we've understood that there was no single point at which the big bang occurred, so there's no center to the universe everything is spreading out from. The big bang happened everywhere at once, and space has continued expanding everywhere at once ever since.
A 3D obj stretched everywhere equally -- I suppose this is the same as the 2D balloon -- as it is also stretched everywhere equally
One says everywhere is equi-distant from the origin in a 4th dimension. The other also says everywhere equi-distant but from zero, but adds a topolgy with no edges
A 3D topology with no edges ofcourse requires a 4th dimension though
So I think these are really two ways of saying the same thing?
--
In any case, it really helped answer some other Qs for me
In a simplistic sense the differences in the Hubble constant, are of course a dimension. So adding dimensions as in string theory is a fancy way of explaining nothing. But I wondered... Is there a correlation between Hubble constant differences and 3D space?
If so, it would (in my unremmitingly small brain) show an interaction with dark energy a.k.a. this 4th dimension
A clearer way to say that: the skin of the balloon has a thickness, and differences in the Hubble constant are measuring that thickness
-- Your answer was awesome and super helpful -- Can you do it a second time? :)
You're operating on a very outdated understanding of what the big bang was - for half a century now we've understood that there was no single point at which the big bang occurred, so there's no center to the universe everything is spreading out from. The big bang happened everywhere at once, and space has continued expanding everywhere at once ever since.
https://physics.stackexchange.com/questions/136860/did-the-b... is a well written explanation, so I won't try to poorly rephrase it here.