Non-exotic conformal structure of weak exotic singularities

TL;DR

This paper investigates the conformal structure of universes with exotic singularities, revealing that such singularities can be represented as constant time hypersurfaces in Penrose diagrams and may be traversable due to their geodesic completeness.

Contribution

It introduces a method to analyze exotic singularities using Penrose diagrams, showing their potential traversability and extending the understanding of conformal structures in such universes.

Findings

Exotic singularities appear as constant time hypersurfaces.

Penrose diagrams for these models have standard structures.

Exotic singularities are potentially traversable due to geodesic completeness.

Abstract

We study the conformal structure of exotic (non-big-bang) singularity universes using the hybrid big-bang/exotic singularity/big-bang and big-rip/exotic singularity/big-rip models by investigating their appropriate Penrose diagrams. We show that the diagrams have the standard structure for the big-bang and big-rip and that exotic singularities appear just as the constant time hypersurfaces for the time of a singularity and because of their geodesic completeness are potentially transversable. We also comment on some applications and extensions of the Penrose diagram method in studying exotic singularities.