All Questions
Tagged with black-holes general-relativity
2,491
questions
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5
answers
554
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High-spin neutron star
Suppose a large neutron star were to be spun-up by a particular pattern of mass-accretion. The increased centrifugal force could presumably mitigate the increased gravity thus delaying gravitational ...
- 3,356
8
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1
answer
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What is a maximal analytic extension?
Can someone explain (as rigorously as possible) what is involved in analytically continuing, say, the Schwarzschild solution to the Kruskal manifold? I understand the two metrics separately but I'm ...
- 8,800
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3
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Do singularities have a "real" as opposed to mathematical or idealized existence?
I was thinking of, for example a Schwarzchild metric at r=0, i.e. the gravitational singularity, a point of infinite density. I realise that there are different types of singularities--timelike, ...
- 4,323
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Does any particle ever reach any singularity inside the black hole?
I am not a professional physicist, so I may say something rubbish in here, but this question has always popped in my mind every time I read or hear anyone speak of particles hitting singularities and "...
user1549
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8
answers
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Flat space limit of the Schwarzschild metric and Hawking temperature
The Schwarzschild metric reduces to the Minkowski metric in the limit of vanishing $M$, but the Hawking temperature which is proportional to $1/M$ diverges in the same limit. This would imply that ...
- 8,800
14
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7
answers
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Binary Black Hole Solution of General Relativity?
This is rather a technical question for experts in General Relativity. An accessible link would be an accepable answer, although any additional discussion is welcome.
GR has well known solutions ...
- 4,743
17
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1
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If two ultra-relativistic billiard balls just miss, will they still form a black hole?
This forum seems to agree that a billiard ball accellerated to ultra-relativistic speeds does not turn into a black hole.
(See recent question "If a 1kg mass was accelerated close to the speed of ...
- 5,759
5
votes
5
answers
525
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A flyby of orbiting supermassive black holes
Consider two supermassive black holes of equal mass orbiting about their common centre of mass. Is it the case that a free-fall trajectory along the axis of rotation would be outside of either event ...
- 3,356
2
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5
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Black Hole Singularities
If two black holes collide and then evaporate, do they leave behind two naked sigularities ore? If there are two, can we know how they interact?
2
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2
answers
640
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How do you explain the observed fact that "black hole" objects move?
As per Newton objects with mass attract each other, and per Einstein this is further explained by saying that mass warps space-time. So a massive object makes a "dent" into space-time,
a gravity well. ...
- 543
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How precisely does a star collapse into a black hole?
I think we all heard general statements like "once big enough star burns out there is nothing to prevent the gravitational collapse ending in a black hole". But I can't remember even seeing the ...
- 23.7k
5
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What kind of systems of black holes satisfy the laws of black hole thermodynamics?
I've come across black holes thermodynamics multiple times recently (both at this site and elsewhere) and some things started bugging me.
For one thing, first law bothers me a little. It is a ...
- 23.7k
4
votes
4
answers
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White Holes and Time-Reversed Oppenheimer-Snyder collapse
So, the canned explanation that I always hear about why the white hole solution of the extended Schwarzschild solution is non-physical is that "The matter distribution cuts off the white hole solution....
- 41.6k
41
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6
answers
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If I fall into an evaporating black hole, where do I end up?
This question has been bothering me for a while. I have a crude hypothesis...
As I understand it, an observer falling into a black hole will cross the event horizon at some specific future (proper) ...
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492
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21
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How does gravity escape a black hole?
My understanding is that light can not escape from within a black hole (within the event horizon). I've also heard that information cannot propagate faster than the speed of light. I assume that the ...
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