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Onyx
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- What is the metric for a bag-of-gold spacetime?
What is the metric for a bag-of-gold spacetime?
There is no simple expression for the metric for this spacetime, since it consists of (at least) two regions with very different properties that are "glued" together. However, a good mathematical treatment can be found in section III (b) of this paper:Onyx said:What is the metric for a bag-of-gold spacetime?
Is that because the gluing process is so complicated?PeterDonis said:There is no simple expression for the metric for this spacetime, since it consists of (at least) two regions with very different properties that are "glued" together. However, a good mathematical treatment can be found in section III (b) of this paper:
https://arxiv.org/abs/0803.4212
Note, though, that this paper requires "A" level background knowledge to properly understand. A "B" level discussion of the "bag of gold" spacetime and its implications is not really possible.
Not really, the black hole interior can be interpreted as a "bag of gold" even without gluing. See https://arxiv.org/abs/1411.2854Onyx said:Is that because the gluing process is so complicated?
Am I correct in assuming that it is just like the OS collapse case, where there has to be two different metrics for two different manifolds? Also, if not a bag of gold, what is this person describing (not a reliable source)?Demystifier said:Not really, the black hole interior can be interpreted as a "bag of gold" even without gluing. See https://arxiv.org/abs/1411.2854
What's OS?Onyx said:Am I correct in assuming that it is just like the OS collapse case, where there has to be two different metrics for two different manifolds?
This interpretation is rather contrived, though. I expressed my reservations about it in this previous thread:Demystifier said:Not really, the black hole interior can be interpreted as a "bag of gold" even without gluing. See https://arxiv.org/abs/1411.2854
Not really, no. The diagrams in Fig. 3 of the paper are fairly straightforward to understand. But the mathematical details required to verify that everything actually can fit together the way those diagrams depict while satisfying the Einstein Field Equation are not.Onyx said:Is that because the gluing process is so complicated?
The "gluing" process at the boundary between two regions follows the same general rules in both cases, yes. But the relationship between the regions is not the same in the two cases.Onyx said:Am I correct in assuming that it is just like the OS collapse case, where there has to be two different metrics for two different manifolds?