### 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 |

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### Keywords

- Cosmological perturbation theory
- Gravity

### ASJC Scopus subject areas

- Physics and Astronomy(all)

### Cite this

*Journal of Cosmology and Astroparticle Physics*, (12), [001]. https://doi.org/10.1088/1475-7516/2006/12/001

**Gravitational backreaction of matter inhomogeneities.** / Gruzinov, A.; Kleban, M.; Porrati, M.; Redi, M.

Research output: Contribution to journal › Article

*Journal of Cosmology and Astroparticle Physics*, no. 12, 001. https://doi.org/10.1088/1475-7516/2006/12/001

}

TY - JOUR

T1 - Gravitational backreaction of matter inhomogeneities

AU - Gruzinov, A.

AU - Kleban, M.

AU - Porrati, M.

AU - Redi, M.

PY - 2006/12/1

Y1 - 2006/12/1

N2 - 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(H2l2/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/c2, where v is the characteristic peculiar velocity.

AB - 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(H2l2/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/c2, where v is the characteristic peculiar velocity.

KW - Cosmological perturbation theory

KW - Gravity

UR - http://www.scopus.com/inward/record.url?scp=42749104289&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=42749104289&partnerID=8YFLogxK

U2 - 10.1088/1475-7516/2006/12/001

DO - 10.1088/1475-7516/2006/12/001

M3 - Article

JO - Journal of Cosmology and Astroparticle Physics

JF - Journal of Cosmology and Astroparticle Physics

SN - 1475-7516

IS - 12

M1 - 001

ER -