All Questions
Tagged with black-holes general-relativity
2,491
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492
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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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Does someone falling into a black hole see the end of the universe?
This question was prompted by Can matter really fall through an event horizon?. Notoriously, if you calculate the Schwarzschild coordinate time for anything, matter or light, to reach the event ...
- 358k
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How can anything ever fall into a black hole as seen from an outside observer?
The event horizon of a black hole is where gravity is such that not even light can escape. This is also the point I understand that according to Einstein time dilation will be infinite for a far-away-...
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Thought experiment - would you notice if you fell into a black hole?
I've heard many scientists, when giving interviews and the like, state that if one were falling into a black hole massive enough that the tidal forces at the event horizon weren't too extreme, that ...
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Is there such thing as imaginary time dilation?
When I was doing research on General Relativity, I found Einstein's equation for Gravitational Time Dilation. I discovered that when you plugged in a large enough value for $M$ (around $10^{19}$ ...
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Can black holes form in a finite amount of time?
One thing I know about black holes is that an object gets closer to the event horizon, gravitation time dilation make it move more slower from an outside perspective, so that it looks like it take an ...
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If the speed of light is constant, why can't it escape a black hole?
When speed is the path traveled in a given time and the path is constant, as it is for $c$, why can't light escape a black hole?
It may take a long time to happen but shouldn't there be some light ...
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5
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Would touching a black hole of a small mass (the mass of an apple) cause you to spiral in and get dead?
I know that a typical stellar black hole would spaghettify someone who crosses its event horizon.
Is this also true for a hypothetical tiny black hole with a small mass (the mass of an apple)? Would ...
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Does black hole formation contradict the Pauli exclusion principle?
A star's collapse can be halted by the degeneracy pressure of electrons or neutrons due to the Pauli exclusion principle. In extreme relativistic conditions, a star will continue to collapse ...
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4
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Would we even notice the merger with the Andromeda Galaxy?
I have read this question:
When galaxies collide it is not that their stars crash into each other, because their individual cross-sections are extremely small when compared to the space between them. ...
- 29k
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Why isn't the circumferential light around the M87 black hole's event horizon symmetric?
After the revelation of the first black hole images, it seems there is a bias towards the south side. Is it because of measuring it from earth or is it something more fundamental in the understanding ...
- 3,366
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5
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Why do physicists trust black hole physics?
Based on popular accounts of modern physics and black holes (articles, video lectures), I have come to understand the following:
Black holes are predicted by General Relativity, a classical theory of ...
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5
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Why is a black hole black?
In general relativity (ignoring Hawking radiation), why is a black hole black? Why nothing, not even light, can escape from inside a black hole? To make the question simpler, say, why is a ...
41
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10
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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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Are black holes very dense matter or empty?
The popular description of black holes, especially outside the academia, is that they are highly dense objects; so dense that even light (as particle or as waves) cannot escape it once it falls inside ...
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