The singularity

Assembled from 11 blocks · 2 evidence · 3 related

1. Story
2. The place where general relativity stops producing answers. Roger Penrose showed in 1965 that once a trapped surface forms - a region where even outward-directed light converges - geodesic incompleteness follows for any matter obeying reasonable energy conditions, without assuming perfect symmetry. That result matters because it removed the previous escape route: collapse to a singular state had been dismissed as an artefact of the idealised spherical calculations of Oppenheimer and Snyder in 1939. What the theorem establishes is that worldlines end, not that infinite density exists at a point. The honest reading is that the singularity is a signpost marking where the theory has left its domain of validity, in the same way that the infinities of classical electrodynamics at the electron radius mark where quantum mechanics is needed. Whether the interior is ever hidden - the cosmic censorship conjecture Penrose proposed in 1969 - remains unproven. Not a place on Earth.
3. Knowledge
4. The singularity
5. Connections
6. Oppenheimer and Snyder compute continued gravitational contraction
7. Penrose proves that collapse to a singularity is generic
8. The Nobel Prize in Physics recognises black holes twice over
9. Evidence
10. Establishes that geodesic incompleteness follows generically from the formation of a trapped surface, without an assumption of symmetry. V55 VERIFICATION BASIS: not consulted in session; no research tool was available. Volume and page are from recall of a canonical citation and must be checked.
11. The first relativistic description of indefinite gravitational collapse, including the divergence between the infalling and distant descriptions of the crossing. V55 VERIFICATION BASIS: not consulted in session; no research tool was available. Volume and page are from recall of a canonical citation and must be checked.