## Re: Big Shell?

Originally Posted by

**OleCuss** One of the worst things done in Physics is to use a balloon to illustrate the expansion of the universe. If properly interpreted it can be somewhat helpful but not very IMHO.

So we end up with people figuring there is a center to the universe because we consider it to be at least as spherical if not more so than the balloon used to illustrate.

We've even got some Astrophysicists and Cosmologists who are stuck thinking that the universe all began with a sort of quantum smear or some other infinitesimal beginning - which is not at all demanded by the observations/science.

Yes, it's a tedious error that gets propagated by some popular figures. But General Relativity is experimentally verified and not falsified by any observations and all those observations plus GR say that the universe is the same everywhere and in all directions on average. It also makes clear that any irregularities due to a shell (with two edges, inner and outer) or a ball with only an outer edge violate momentum and angular momentum conservation.

Emmy Noether proved the maths back in 1915 and it's actually more general than General Relativity. Her proof applies to any physical theory classical or quantum, relativistic or not. I suspect that the equation:

homogenous isotropic universe = momentum and angular momentum conservation

has to hold in any physics theory that could be invented.

I'm simply staggered that popularizers of science don't realize this cornerstone of physics applies to and refutes some of their ravings.

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