## Abstract

The non-linearity of Einstein's equations makes it possible for small scale matter inhomogeneities to affect the universe at cosmological distances. We study the size of such effects using a simple heuristic model that captures the most important backreaction effect due to non-relativistic matter, as well as several exact solutions describing inhomogeneous and anisotropic expanding universes. We find that the effects are O(H^{2}l^{2}/c ^{2}) or smaller, where H is the Hubble parameter and l the typical size scale of inhomogeneities. For virialized structures this is of order v ^{2}/c^{2}, where v is the characteristic peculiar velocity.

Original language | English (US) |
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Article number | 001 |

Journal | Journal of Cosmology and Astroparticle Physics |

Issue number | 12 |

DOIs | |

State | Published - Dec 1 2006 |

## Keywords

- Cosmological perturbation theory
- Gravity

## ASJC Scopus subject areas

- Astronomy and Astrophysics