Inhomogeneous Cosmology Redux

TL;DR

This paper explores an inhomogeneous void cosmology model as an alternative to dark energy, addressing multiple observational anomalies and tensions in standard cosmology through solutions based on the Lemaître-Tolman-Bondi model.

Contribution

It demonstrates that a void cosmology model can resolve key observational tensions and anomalies without invoking dark energy, offering a viable alternative to the standard Lambda-CDM model.

Findings

Resolves Hubble constant discrepancy between local and Planck measurements.

Addresses lithium abundance mismatch in big bang nucleosynthesis.

Explains cluster count and CMB lensing anomalies.

Abstract

An alternative to the postulate of dark energy required to explain the accelerated expansion of the universe is to adopt an inhomogeneous cosmological model to explain the supernovae data without dark energy. We adopt a void cosmology model, based on the inhomogeneous Lema\^{i}tre-Tolman-Bondi solution of Einstein's field equations. The model can resolve observational anomalies in the $\Lambda CDM$ model, such as the discrepancy between the locally measured value of the Hubble constant, $H_0=73.24\pm 1.74\,{\rm km}\,{\rm s}^{-1}\,{\rm Mpc}^{-1}$, and the $H_0=66.93\pm 0.62\,{\rm km}\,{\rm s}^{-1}\,{\rm Mpc}^{-1}$ determined by the Planck satellite data and the $\Lambda CDM$ model, and the lithium $^{7}{\rm Li}$ problem, which is a $5\sigma$ mismatch between the theoretical prediction for the $^{7}{\rm Li}$ from big bang nucleosynthesis and the value that we observe locally today at $z=0$. The void model can also resolve the tension between the number of massive clusters derived from the Sunyaev-Zel'dovich effect by the Planck satellite and the number expected from the CMB anisotropies, and the CMB weak lensing anomaly observed in the Planck data. The cosmological Copernican principle and the time and position today coincidence conundrums in the $\Lambda CDM$ and void cosmological models are discussed.