Black Holes and Cosmological Models

Abstract

There are fundamental problems and tensions in cosmology that suggest that our current formalism for the description of the Universe is the approximation of a better story. The main motivation of this work is related to the efficient resolution of some current cosmological problems associated with the initial conditions of our Universe. With the current formalism, today’s Universe had to start in an extremely particular state. A minor deviation from its initial conditions would not support the current phenomenological data. In the present work, we study a cosmological model solely based on general relativity, referred to as the reversed black hole Universe. The Universe is modelled by a dust-filled Friedmann model with two extra components. First, the Universe is assumed to be inside a Schwarzschild black hole. Second, observers in the black hole Universe see a time flow that goes in the opposite direction to that of the observers outside the black hole. With time flowing in the opposite direction in the interior, however, the precise fine-tuning of the initial conditions is equivalent, from the exterior, to a Universe which ends up in a very particular final state, which is no longer a problem in itself.