4 ms·
Tangent, but: Kip Thorne once commented that black holes are “bigger across” than we’d expect from their circumference. Which I think is what those cusp-on-she
by zmgsabst 2y ago
Tangent, but:
Kip Thorne once commented that black holes are “bigger across” than we’d expect from their circumference. Which I think is what those cusp-on-sheet models are showing.
Does that create a topological defect?
I ask because a circle around a cusp in a sheet will get “caught” on the infinite spike; and a circle not around the cusp will end up with weird deformations if it comes close. That suggests there’s something “topological” about such a cusp, akin to there being a hole.
- pdonis 2y ago> Kip Thorne once commented that black holes are “bigger across” than we’d expect from their circumference. Which I think is what those cusp-on-sheet models are showing. Does that create a topological defect? No. There are no topological defects in any of the standard black hole spacetimes.
- nyssos 2y ago> I ask because a circle around a cusp in a sheet will get “caught” on the infinite spike; and a circle not around the cusp will end up with weird deformations if it comes close. That suggests there’s something “topological” about such a cusp, akin to there being a hole. Your intuition is right, this is an example of a topological defect, but it's not directly related to circles having the "wrong" sizes. It's topological in that it's just a property of how your sheet is connected, and can't be changed by continuous deformations. Black holes are not topological defects in the same way, because they're not really "infinite spikes".