Timeline for Some Mathematical Questions on Gravitational Waves and Numerical Relativity
Current License: CC BY-SA 3.0
9 events
| when toggle format | what | by | license | comment | |
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| Oct 25, 2017 at 2:30 | comment | added | Willie Wong | @Transcendental: regarding the final question, "not quite". The method (as far as I understand) used by numerical relativists work because they already started with black hole solutions (from which light/signals/information cannot classically escape). My comment about weak cosmic censorship concerns the hypothetical question you may have had "what if I want to know about how singularities interact with gravitational waves?" To which I would respond "if you believe in WCC then this is a moot point." Does that make sense? | |
| Oct 25, 2017 at 0:58 | vote | accept | Transcendental | ||
| Oct 24, 2017 at 18:12 | comment | added | Transcendental | Just one more question, Willie. If I read you correctly, the excision method is used by numerical relativists under the assumption of the weak cosmic censorship hypothesis? | |
| Oct 24, 2017 at 18:05 | comment | added | Transcendental | Thanks for the clarification. As for the source that you’ve requested, it’s this video clip created by the SXS Project. After reading your comments, I watched it more carefully and realized (after all this time) that its use of a color-enhanced rubber-sheet analogy indeed doesn’t account for regions very close to the singularities. This wasn’t apparent at first because the (black) excised regions were blocked from view. Beneath the clip is an explanation of the color scheme, but it doesn’t mention anything about the excised regions. | |
| Oct 24, 2017 at 13:01 | comment | added | Willie Wong | @Transcendental: also, I think you misunderstood my answer: the key idea I try to mention is not that the singularity is not part of the space-time, but that singularities are expected to be (by some) to be generically space-like or null, and it doesn't make too much sense to speak of them as moving. (In the Schwarzschild picture, the singularity is the future terminus of all observers who enter the horizon. It is not a point you move toward because you travel in space, but a line you move toward because you travel in time.) | |
| Oct 24, 2017 at 12:57 | comment | added | Willie Wong | @Transcendental: can you point me to the source where you found that "singularities are represented as points in $\mathbb{R}^3$"? The only method I have even a passing familiarity with is the excision method, and I had thought that the excised region is most of the black hole, and we don't go near the singularity at all. If you believe weak cosmic censorship, there's not much point of keeping track of the singularity at all for gravitational waves. | |
| Oct 24, 2017 at 7:33 | comment | added | Transcendental | Hello Willie. Thanks for your response. I understand that singularities aren’t part of space-time, so there’s no such thing as singularities moving in space-time. However, in computer simulations that show the evolution of binary black holes, it appears that singularities are represented as points in $ \mathbb{R}^{3} $ with time-dependent coordinates. I was asking my question in that context. | |
| Oct 23, 2017 at 16:39 | history | edited | Willie Wong | CC BY-SA 3.0 |
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| Oct 23, 2017 at 15:26 | history | answered | Willie Wong | CC BY-SA 3.0 |