Black Holes as Dark Matter

TL;DR

This paper explores the hypothesis that black holes constitute all dark matter, emphasizing their dominant contribution to the universe's entropy and discussing the cosmological implications of this idea.

Contribution

It proposes that dark matter is entirely composed of black holes, providing a statistical mechanics perspective and analyzing the cosmological history of dark matter.

Findings

Black holes account for nearly all cosmological entropy.

Dark matter may be entirely made of black holes.

The cosmological history supports black holes as dark matter candidates.

Abstract

While the energy of the universe has been established to be about 0.04 baryons, 0.24 dark matter and 0.72 dark energy, the cosmological entropy is almost entirely, about $(1 - 10^{-15})$, from black holes and only $10^{-15}$ from everything else. This identification of all dark matter as black holes is natural in statistical mechanics. Cosmological history of dark matter is discussed.