Effect of sources on the inner horizon of black holes

Abstract

A single pulse of null dust and colliding null dust both transform a regular horizon into a spacelike singularity in the space of colliding waves. The local isometry between such space-times and black holes extrapolates these results to the realm of black holes. However, the inclusion of particular scalar fields instead of null dust creates null singularities rather than spacelike ones on the inner horizons of black holes.