Timelike and null focusing singularities in spherical symmetry: a solution to the cosmological horizon problem and a challenge to the cosmic censorship hypothesis

TL;DR

This paper explores specific spherically symmetric singularities that could solve the cosmological horizon problem without inflation and challenge the cosmic censorship hypothesis by providing new solutions with particular energy conditions.

Contribution

It identifies new classes of timelike and null singularities within spherical symmetry that have implications for cosmology and the cosmic censorship hypothesis.

Findings

Potential resolution of the horizon problem without inflation.

Counter-examples to the Strong Cosmic Censorship Hypothesis.

Identification of singularity solutions with radiative perfect fluid stress-energy tensor.

Abstract

Extending the study of spherically symmetric metrics satisfying the dominant energy condition and exhibiting singularities of power-law type initiated in SI93, we identify two classes of peculiar interest: focusing timelike singularity solutions with the stress-energy tensor of a radiative perfect fluid (equation of state: $p={1\over 3} \rho$) and a set of null singularity classes verifying identical properties. We consider two important applications of these results: to cosmology, as regards the possibility of solving the horizon problem with no need to resort to any inflationary scenario, and to the Strong Cosmic Censorship Hypothesis to which we propose a class of physically consistent counter-examples.