An Event Horizon 'Firewall' Undergoing Cosmological Expansion

TL;DR

This paper explores a cosmological model with a singular horizon similar to a black hole's, embedded in an expanding universe with a positive cosmological constant, revealing a dynamic horizon with singularities and observable implications.

Contribution

It introduces a novel cosmological horizon model with singularities, differing from traditional black holes, and analyzes its properties within an expanding universe framework.

Findings

The horizon exhibits temperature and pressure singularities.

An expanding light front separates affected and unaffected regions.

The model's Hubble constant can match current observations.

Abstract

We embed an object with a singular horizon structure, reminiscent of (but fundamentally different from, except in a limiting case) a black-hole event horizon, in an expanding, spherically symmetric, homogeneous, Universe that has a positive cosmological constant. Conformal representation is discussed. There is a temperature/pressure singularity and a corresponding scalar curvature singularity at the horizon. The expanding singular horizon ultimately bounds the entire space-time manifold. It is is preceded by an expanding light front, which separates the space-time affected by the singularity from that which is not yet affected. An appropriately located observer in front of the light front can have a Hubble-Lema\^itre constant that is consistent with that currently observed.