Black hole singularity is a surface not a point

	Black hole singularity is a surface not a point(arxiv.org)
	294 points by raattgift 16 days ago \| 205 comments
	tl;dr: Two observers free-falling into a spherical black hole along different angular paths lose causal contact well before reaching the center, meaning the singularity is effectively a 2D surface rather than a point. For rotating black holes, the singular surface likely forms at the inner horizon via the mass inflation instability. The authors argue this has implications for quantum gravity: a black hole's quantum states probably live on this 2D singular surface, evolving unitarily with the trapped Hawking radiation inside the event horizon.
	HN Discussion: ↑This is not new; any GR grad student knows singularities aren't points, just correcting popsci tropes •Curious question about whether GR equations permit singularities extending beyond event horizons ↓Alternative theoretical framing suggesting multiple temporal dimensions would dissolve singularity debates entirely ~Seeking clarification on whether the article is simply restating standard event horizon vs central singularity distinctions ↑Supporting reference to Penrose diagrams as visualization of the causal structure claim