Time-Symmetrization and Isotropization of Stiff-Fluid Kantowski-Sachs Universes

TL;DR

This paper demonstrates that stiff-fluid Kantowski-Sachs universes naturally evolve towards time-symmetry and isotropy without inflation, offering an alternative explanation for the universe's large-scale flatness.

Contribution

It introduces a mechanism where stiff-fluid universes become symmetric and isotropic over time without requiring inflationary expansion.

Findings

Universes become time-symmetric from asymmetric initial conditions.

Isotropization occurs without an inflationary era.

The universe approaches flatness through natural evolution.

Abstract

It is shown that growing-entropy stiff-fluid Kantowski-Sachs universes become time-symmetric (if they start with time-asymmetric phase) and isotropize. Isotropization happens without any inflationary era during the evolution since there is no cosmological term here. It seems that this approach is an alternative to inflation since the universe gets bigger and bigger approaching 'flatness'.