Why we need dark energy

TL;DR

This paper argues that dark energy or an equivalent component is essential for the universe to behave like a typical thermodynamic system, allowing it to reach equilibrium in the long term.

Contribution

It introduces the necessity of dark energy for the universe to function as a thermodynamic system tending toward equilibrium.

Findings

Dark energy is necessary for thermodynamic equilibrium.

The universe's long-term behavior depends on a dynamically equivalent component.

Supports the view that dark energy influences cosmic thermodynamics.

Abstract

It is argued that dark energy -or something dynamically equivalent at the background level- is necessary if the expanding universe is to behave as an ordinary macroscopic system; that is, if it is to tend to some thermodynamic equilibrium state in the long run.