Black hole singularity is a surface, not a point

Black hole singularity is a surface not a point

A new paper argues that the singularity at the center of a black hole is not a point but a surface. Two observers falling into a spherical black hole along different angular trajectories lose causal contact well before reaching the center, illustrating that in general relativity, points can be spatially close yet causally distant. For rotating black holes, the singular surface likely resides at the inner horizon, where perturbations trigger exponential mass inflation. The authors suggest that quantum gravity states of a black hole may reside on this 2D surface, coevolving with trapped Hawking radiation.