Why do naked singularities form in gravitational collapse?

TL;DR

This paper explores the physical conditions, especially shear effects, that lead to naked singularities forming instead of black holes during spherical gravitational collapse, highlighting the role of apparent horizon delay.

Contribution

It identifies shear effects as a key factor in delaying apparent horizon formation, revealing conditions that produce naked singularities.

Findings

Strong shear delays apparent horizon formation

Naked singularities occur when apparent horizon is delayed

Shear effects are crucial in gravitational collapse outcomes

Abstract

We investigate what are the key physical features that cause the development of a naked singularity, rather than a black hole, as the end-state of spherical gravitational collapse. We show that sufficiently strong shearing effects near the singularity delay the formation of the apparent horizon. This exposes the singularity to an external observer, in contrast to a black hole, which is hidden behind an event horizon due to the early formation of an apparent horizon.