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Chalnoth
#39
Sep12-10, 03:53 AM
Sci Advisor
P: 4,800
Quote Quote by twofish-quant View Post
You still have big bang nucleosynthesis to worry about, and then there is galaxy count information.
Indeed, mentioned the primordial helium abundance :)

Quote Quote by twofish-quant View Post
You could get really crazy and then reject GR and redshifts altogether, but at that point you've blown away the Milne model in addition to standard cosmologies. If you don't think that redshifts are caused by Hubble flow, that's interesting, but then you are rejecting all of the supernova and CMB data, at which point I don't see how looking at the details are going to be useful.

It's generally considered rude to pick and choose what data you think is valid and which ones you think aren't, but the fun thing about this discussion is that even if you cherry pick data, you are going to find it difficult to get anywhere close to the Milne model.
Yup. Well, there's a large degeneracy in the supernova data with regard to the total energy density of the universe. It measures reasonably accurately the ratio of matter (normal + dark) to dark energy, but it doesn't do so well at measuring the total. Because of this, early supernova experiments taken alone were quite consistent with a Milne cosmology (except for the whole issue of the universe not being empty).

But this degeneracy isn't perfect, and more recent supernova experiments which have much more data rule out the Milne cosmology rather well. Of course, once you combine them with something like WMAP or BAO, the Milne cosmology becomes so far out of bounds of observation that the whole idea becomes patently absurd.