Hearts of Darkness: The inside out probing of black holes

Classical black holes shield us from the singularities that inevitably appear in general relativity. Singularity regularization being one of the main landmarks for a successful theory of quantum gravity, quantum black holes are not obliged to hide their inner core from the outside world. Notwithstanding the aforesaid, it is often implicitly assumed that quantum gravity effects must remain confined to black hole interiors. In this essay, we argue in the opposite direction, discussing theoretical evidence for the existence of strong correlations between the physics inside and outside nonsingular black holes. We conclude that astronomical tests of the surroundings of black holes can provide invaluable information about their so-far unexplored interiors.

Automated summary

Classical black holes can shield singularities in general relativity, but quantum black holes may reveal their inner core. It is usually assumed that quantum gravity effects are limited to black hole interiors, but this essay argues for strong correlations between interior and exterior physics in nonsingular black holes, suggesting that astronomical tests could provide valuable insights into unexplored black hole interiors.