Horizon Shells: Classical Structure at the Horizon of a Black Hole

Abstract

We address the question of the uniqueness of the Schwarzschild black hole by considering the following question: How many meaningful solutions of the Einstein equations exist that agree with the Schwarzschild solution (with a fixed mass m) everywhere except maybe on a codimension one hypersurface? The perhaps surprising answer is that the solution is unique (and uniquely the Schwarzschild solution everywhere in spacetime) *unless* the hypersurface is the event horizon of the Schwarzschild black hole, in which case there are actually an infinite number of distinct solutions. We explain this result and comment on some of the possible implications for black hole physics.

1+5 pages, Essay written for the Gravity Research Foundation 2016 Awards for Essays on Gravitation, based on arXiv:1512.02858

Cited by in corpus (8)

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• Soft hairy horizons in three spacetime dimensions
• Memory Effect and BMS-like Symmetries for Impulsive Gravitational Waves
• The region interior to the event horizon of the Regular Hayward Black Hole
• Soft hairs on isolated horizon implanted by electromagnetic fields
• Memory effect and BMS symmetries for extreme black holes
• Soldering freedom and BMS-like transformations
• Supertranslations: redundancies of horizon data, and global symmetries at null infinity