Shear-free gravitational collapse is strongly censored

TL;DR

This paper proves that shear-free gravitational collapse cannot produce locally naked singularities, suggesting shear is essential for such phenomena, and contributes to understanding cosmic censorship in spherically symmetric spacetimes.

Contribution

It establishes that shear-free collapse cannot lead to locally naked singularities, advancing the theoretical understanding of singularity formation and visibility.

Findings

Shear-free collapse cannot admit locally naked singularities

Shear is likely necessary for the occurrence of locally naked singularities

Supports the cosmic censorship conjecture in shear-free scenarios

Abstract

We consider spherically symmetric spacetimes with matter whose timelike flow is assumed to be shear-free. A number of results on the formation and visibility of spacetime singularities is proven, with the main one being that shear-free collapse cannot admit locally naked singularities (which implies absence of globally naked singularities). We conjecture that shear is a necessary condition for the occurrence of locally naked singularities in generic gravitational collapse.