Gravitational Merging as a Possible Source for the Cosmological Accelerating

TL;DR

This paper explores how gravitational merging and clustering of cosmic objects could explain the universe's accelerated expansion by introducing a correction to the cosmic fluid's equation of state, highlighting the role of voids in generating negative pressure.

Contribution

It proposes a novel correction to the cosmic fluid's equation of state due to merging, suggesting voids as a source of acceleration, and connects this to observational constraints on dark energy.

Findings

Merging introduces a $b ho^2$ correction in the equation of state.

Voids provide negative pressure contributing to acceleration.

Merging of voids can explain the observed acceleration of the universe.

Abstract

Gravitational merging (or clustering) of cosmic objects is regarded as a possible source of the extra-acceleration of the universe at large scale. The merging/clustering of cosmic objects introduces a correction term in the equation of state for the effective present cosmic fluid in the form of $P=w\rho+b\rho^2$. As a result, an alternative relation for the energy density includes over and under-dense regions is obtained that coincide with the conventional relation in the standard limit. By analogy with bubbles, the under-dense regions (voids) in the cosmic fluid is shown to provide the needed negative pressure. Invoking the observational constraint for the dark energy equation of state $w$, we show that the merging of voids will act as a possible source of extra-accelerating at large scale in comparison with non-merging cosmic gas.