On the nature of cosmological time

TL;DR

This paper proposes a novel cosmological model where time flow depends on the universe's entropy, explaining supernova data without dark matter or dark energy.

Contribution

It introduces a hypothesis linking cosmological time to entropy, offering an alternative to standard models that require dark components.

Findings

Successfully fits Type Ia Supernovae data

Eliminates need for dark matter and dark energy

Provides a thermodynamic basis for cosmological time

Abstract

Time is a parameter playing a central role in our most fundamental modeling of natural laws. Relativity theory shows that the comparison of times measured by different clocks depends on their relative motions and on the strength of the gravitational field in which they are embedded. In standard cosmology, the time parameter is the one measured by fundamental clocks, i.e. clocks at rest with respect to the expanding space. This proper time is assumed to flow at a constant rate throughout the whole history of the Universe. We make the alternative hypothesis that the rate at which cosmological time flows depends on the dynamical state of the Universe. In thermodynamics, the arrow of time is strongly related to the second law, which states that the entropy of an isolated system will always increase with time or, at best, stay constant. Hence, we assume that time measured by fundamental clocks is proportional to the entropy of the region of the Universe that is causally connected to them. Under that simple assumption, we build a cosmological model that explains the Type Ia Supernovae data (the best cosmological standard candles) without the need for exotic dark matter nor dark energy.