Eternally oscillating zero energy Universe

TL;DR

This paper explores oscillatory and non-oscillatory universe models within a modified gravity theory, fitting supernova data and analyzing implications for cosmic curvature and energy components.

Contribution

It introduces oscillatory solutions in THED gravity that fit supernova data and differ from standard models by predicting significant negative spatial curvature.

Findings

Oscillatory solutions fit supernova data with low dark matter and negative curvature.

Ever-expanding solutions require higher matter density and positive dark energy.

CMB analysis suggests significant negative spatial curvature.

Abstract

The question of whether the universe is eternal or if it had a singular moment of creation is deeply intriguing. Although different versions of steady state and oscillatory models of eternal universe have been envisaged, empirical evidence suggests a singular moment of creation at the big bang. Here we analyze the oscillatory solutions for the universe in a modified theory of gravity THED (Torsion Hides Extra-Dimension) and evaluate them by fitting Type 1a supernovae redshift data. THED-gravity exactly mimics General Relativity at the kinematical level, while the modifications in its dynamical equations allow the universe to bounce between a minimum size and a maximum size with a zero average energy within each oscillation. The optimally fit oscillatory solutions correspond to a universe with (i) a small matter density requiring little to no dark matter, (ii) a significantly negative spatial curvature, (iii) a tiny negative dark energy. Alternatively, there exists non-oscillating solutions that appear as an ever-expanding universe from a single bounce preceded by a collapse from the infinite past. These ever-expanding solutions provide marginally better fits to the supernova redshift data, but require larger matter densities and positive dark energy along with a positive spatial curvature. A qualitative analysis of CMB power spectrum in the modified theory suggests a significant negative spatial curvature, which is in stark contrast to a near-zero curvature in the standard big bang theory. An independent constraint on the spatial curvature can further shed light on discriminating the ever expanding and oscillatory universe scenarios.