All Questions
Tagged with spacetime black-holes
322
questions
3
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0
answers
319
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Is it mathematically possible or topologically allowable for cutouts, or cavities, to exist in a 3-manifold?
A few weeks back, I posted a related question, Could metric expansion create holes, or cavities in the fabric of spacetime?, asking if metric stretching could create cutouts in the spacetime manifold. ...
- 513
23
votes
2
answers
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Does a charged or rotating black hole change the genus of spacetime?
For a Reissner–Nordström or Kerr black hole there is an analytic continuation through the event horizon and back out. Assuming this is physically meaningful (various site members hereabouts think not!)...
- 358k
17
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6
answers
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Is it possible for one black hole to pull an object out of another black hole?
Suppose we have a spacecraft just inside the event horizon of a black hole, struggling to escape, but slowly receding into it. Another (bigger) black hole expands until its event horizon includes the ...
- 2,784
1
vote
1
answer
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Classical black holes?
How big should the black hole be so we can consider it to be classical?
When they claim that we can not probe shorter distances than the Planck length, can it be true?
The argument says that, doing ...
- 2,586
8
votes
1
answer
796
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Do spacelike junctions in the Thin-Shell Formalism imply energy nonconservation and counterintuitive wormholes?
The Thin Shell Formalism (MTW 1973 p.551ff) is used to properly paste together different vacuum solutions to the Einstein equations. At the junction of the two solutions is a hypersurface of matter – ...
- 668
13
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4
answers
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Can a black hole be explained by Newtonian gravity?
In the simple explanation that a black hole appears when a big star
collapses under missing internal pressure and huge gravity, I can't see
any need to invoke relativity. Is this correct?
- 1,436
22
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3
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If the observable universe were compressed into a super massive black hole, how big would it be?
I understand only a little of general relativity, but that's why I'm here! :)
Consider the hypothetical situation of some extra-terrestrial intelligence pushing all the mass in the observable ...
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