Light propagation through large-scale inhomogeneities in the Universe and its impact on cosmological observations

TL;DR

This paper investigates how large-scale inhomogeneities in the universe affect cosmological observations, using exact solutions to Einstein's equations, and finds their impact is generally small.

Contribution

It employs inhomogeneous exact solutions like Lemaître-Tolman and Szekeres models to analyze cosmological data without assuming small density contrasts.

Findings

Supernova data can be fitted without a cosmological constant.

Inhomogeneities of observed sizes have minimal impact on observations.

The analysis challenges the necessity of dark energy in explaining supernova data.

Abstract

This paper analyses cosmological observations within inhomogeneous and exact solutions of the Einstein equations. In some way the analyses presented here can be freed from assumptions such as small amplitude of the density contrast. The supernova observations are analysed using the Lema\itre-Tolman model and the CMB observations are analysed using the quasispherical Szekeres model. The results show that it is possible to fit the supernova data without the cosmological constant. However if inhomogeneities of sizes and amplitudes as observed in the local Universe are considered, their impact on cosmological observations is small.