The Averaging Problem in Cosmology

TL;DR

This thesis investigates the averaging problem in cosmology, analyzing correction terms in Einstein's equations, and finds that these terms are too small to explain the universe's late-time acceleration attributed to dark energy.

Contribution

It applies and refines averaging schemes to evaluate correction terms, demonstrating their negligible impact on cosmic acceleration.

Findings

Averaging correction terms are negligible in magnitude.

These terms cannot account for dark energy effects.

Careful calculation confirms the insignificance of these correction terms.

Abstract

This thesis deals with the averaging problem in cosmology, which has gained considerable interest in recent years, and is concerned with correction terms (after averaging inhomogeneities) that appear in the Einstein equations when working on the large scales appropriate for cosmology. It has been claimed in the literature that these terms may account for the phenomenon of dark energy which causes the late time universe to accelerate. We investigate the nature of these terms by using averaging schemes available in the literature and further developed to be applicable to the problem at hand. We show that the effect of these terms when calculated carefully, remains negligible and cannot explain the late time acceleration.