Ring criterion

The ring criterion is a concept from the general theory of relativity , which is supposed to enable the decision whether a compact object collapses into a black hole or not. An object of mass satisfies the ring criterion if it is compact enough to fit through the opening of a ring of circumference (in any orientation) , where is the Schwarzschild radius associated with object mass . ${\displaystyle M}$ ${\displaystyle 2\pi R_{S}}$ ${\displaystyle R_{S}=2GM/c^{2}}$

A hitherto unproven, but confirmed by all known descriptions of black holes, conjecture ( hoop conjecture ) by the American physicist Kip Thorne states that any body that is compact enough to meet the ring criterion will collapse into a black hole.

Thorne also assumed even more strongly that this is also a sufficient condition (if and only then, if the ring criterion is met, a black hole forms). Usually the assumption is interpreted in such a way that for the formation of a black hole a collapse must take place in all three spatial dimensions, with two (“pancake” -like scenario) or one dimension, on the other hand, naked singularities arise (violation of cosmic censorship, which Thorne thinks is possible holds).

literature

• Kip Thorne: Nonspherical Gravitational Collapse - A Short Review . In: John R. Klauder (Ed.): Magic without Magic. John Archibald Wheeler. A collection of essays in honor of his sixtieth birthday . Freeman, San Francisco 1972, ISBN 0-7167-0337-8 , pp. 231-258.

Individual evidence

1. ↑ Thorne in Klauder, Magic without magic, 1972, p. 237
2. ^ R. Wald, Gravitational collapse and cosmic censorship, 1997, Arxiv