Re: Feo3: the universe

Posted by Pasti on Feb 10, 2004 at 17:24

(64.7.138.66)

Re:Feo3: the universe (Feo Amante)"If were to find out that the Universe had a true horizon twice what we now believe, wouldn't that, with only a very minor modification of the homogeneous and isotropic universe model, still fit withiin the framework of Einstien's hypothesis?"

You are right,it would still fit Einstein's equations.But this is beyond the point, in the sense that numerical coefficients for every theory come from experimental observations.And in cosmology, as in electromagnetism, these experimental observations are consistent, and they come from different principial and observational sources.

By the same token, Maxwell's equations (the whole electromagnetism,and QED,QCD)can be considered wrong,since they accomodate, say, almost any dispersion relation, and almost any refractive index.But this does not mean it is wrong.As long as it can make accurate predictions (reasonably accurate for cosmology, at this time), the theory is OK.Te fact that it can describe several situations is a plus in this case.

String theory, on the other hand,outputs very nice results, but makes no predictions.In cosmology, the major source of errors is the distance measurement at large scale, which in turn affects the accuracy of the Hubble function (what used to be called the Hubble constant, which in fact is not a constant)