How unique are the Friedmann-Robertson-Walker models of the universe?
Abstract
By accepting the validity of certain conjectures in classical general relativity and kinetic theory, it is argued that, in a sense, the spatially homogeneous and isotropic Friedmann-Robertson-Walker (FRW) cosmological models are unique. This is accomplished in two steps. First, there is reason to believe that kinetic theory requires perfect fluids to be shear-free. Second, it seems that general relativity constrains expanding shear-free fluids to be irrotational. The uniqueness of the FRW models then follows, since it has already been established that they are the only space-times which represent an expanding shear-free irrotational perfect fluid that are physically reasonable on a global scale.
- Publication:
-
General Relativity and Gravitation
- Pub Date:
- May 1987
- DOI:
- 10.1007/BF00760653
- Bibcode:
- 1987GReGr..19..493C
- Keywords:
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- Cosmology:Friedmann Universe;
- Cosmology:General Relativity;
- General Relativity:Cosmology