Timeline for Membrane-reversed black holes and their relationship to white-holes
Current License: CC BY-SA 3.0
6 events
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| Jul 10, 2013 at 19:21 | comment | added | Zo the Relativist | I would also argue that Ben Crowell's second penrose diagram is probably not the right one to be using in this case. You'd be better off doing something like writing down a Vaidya solution for a shrinking mass profile, and then going through the whole conformal transform procedure again. A spacetime that has a black hole that has evaporated is not a perturbation of a schwarzshild spacetime, it's a completely new one. | |
| Jul 10, 2013 at 19:14 | comment | added | Zo the Relativist | @lurscher: within a particular time slicing every point in a FRLW spacetime has a distinct cosmological horizon. In a Schwarzshild spacetime, and for a given time slicing, there is only one apparent horizon. The fact that we're fixing the time slicing and using apparent horizons and not event horizons gets rid of the issue of shrinking black holes, since the horizon may have shrunk at a future time, but it is still there. They are distinct events. | |
| Jul 10, 2013 at 18:09 | comment | added | lurscher | well, that is debatable. Classically yes, but as this question (physics.stackexchange.com/q/22498/955) highlights very clearly, the physical event horizon of black holes that have formed in a finite time are diffuse, they are not infinitely resolved as the eternal black hole solutions we are used to studying on classical gravity. Real black holes evaporate, so the physical horizon is not precisely located. Hence, I don't see this difference as clear-cut. Maybe we should think about this some more? | |
| Jun 10, 2013 at 17:30 | comment | added | Zo the Relativist | the CEH horizon is observer-dependent--a horizon only exists relative to a point. In a black hole spacetime, all observers agree on where the horizon is. | |
| Jun 10, 2013 at 16:32 | comment | added | lurscher | i really don't see a physical difference between one kind of horizon (black holes) or the other (CEH), besides the sense in which useful information flows | |
| Jun 9, 2013 at 19:50 | history | answered | Zo the Relativist | CC BY-SA 3.0 |