Inhomogeneity effects in Cosmology

TL;DR

This paper explores how inhomogeneous spacetime models can impact cosmological observations and theories, potentially explaining cosmic acceleration without dark energy by considering effects of inhomogeneity and backreaction.

Contribution

It analyzes the effects of inhomogeneity on large-scale dynamics, observations, and the possibility of a universe inhomogeneous on Hubble scales, challenging standard cosmological assumptions.

Findings

Backreaction effects influence large-scale cosmological dynamics.

Local inhomogeneities can significantly affect observational parameters.

Inhomogeneity on Hubble scales may explain cosmic acceleration without dark energy.

Abstract

This article looks at how inhomogeneous spacetime models may be significant for cosmology. First it looks at how the averaging process may affect large scale dynamics, with backreaction effects leading to effective contributions to the averaged energy-momentum tensor. Secondly it considers how local inhomogeneities may affect cosmological observations in cosmology, possibly significantly affecting the concordance model parameters. Thirdly it presents the possibility that the universe is spatially inhomogeneous on Hubble scales, with a violation of the Copernican principle leading to an apparent acceleration of the universe. This could perhaps even remove the need for the postulate of dark energy.