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Perturbations to the Cosmological Expansion in a Grainy Universe

Brett Bochner
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Abstract

The matter content of the Universe is generally regarded as a perfect fluid on sufficiently large scales, for all epochs. But the recent cosmological matter distribution, consisting of an (ideally) random distribution of gravitationally collapsed structures, is more accurately described as a collection of discrete grains, than as a fluid. It is well known that granular materials may have very different macroscopic properties than fluids; analogously, we investigate the possibility that pervasive small-scale inhomogeneities in the recent Universe may lead to perturbations of the cosmological expansion on intermediate and/or large scales.

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Brett Bochner. 2007-02-27. Perturbations to the Cosmological Expansion in a Grainy Universe. https://arxiv.org/abs/astro-ph/0702703

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