All Questions
16
questions
0
votes
1
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76
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Black Hole Formation -- How Can an Event Horizon be Observed to Grow? [duplicate]
This is a question about black hole formation. To be clear, I’m not suggesting that black holes don’t form. It’s that I’m having trouble with the accepted explanation so there’s a flaw in my logic ...
- 21
0
votes
0
answers
45
views
What is the difference between the cosmological and the black hole horizons in thermodynamics?
I want to know the different thermal behaviors between cosmological and black hole horizons, such as temperature, entropy and so on.
- 113
2
votes
1
answer
148
views
Negative $\Lambda$ FLRW spacetimes as infinite black holes?
Consider the Friedmann equation:
$$H^2+\frac{k}{a(t)^2} = \frac{\Lambda}{3}+\frac{8 \pi}{3}\rho$$
and set the parameters for dust in either flat euclidean or open hyperbolic spatial slices with a ...
- 125
0
votes
1
answer
191
views
Are black holes the edge of our universe?
Are black holes the actual edge of the universe? Because spacetime is another dimension, I would assume the universe doesn’t have perceived corners or edges. At least humans cannot perceive it.
The ...
- 11
3
votes
0
answers
61
views
Hypothetically, could the interior of a black hole look exactly like the universe that surrounds us?
I do understand that we can't experimentally verify anything we imagine about the interior of a black hole.
If we were to apply what we know about the physics of the observable universe and assume ...
- 33
1
vote
0
answers
22
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Big Crunchs and Event horizons [duplicate]
There are Two different defintions for the event horizon of a black hole.
The Absolute horizon and the Apparent horizon.
An apparent horizon is a surface that is the boundary between light rays that ...
- 2,908
16
votes
2
answers
551
views
Mathematical coincidence of the Schwarzschild radius of the Universe?
I read here that a black hole with a mass of the observable universe, $M=8.8\times10^{52}kg$, would have a Schwarzschild radius of $r_s=13.7$ billion lightyears.
I immediately noticed that at the ...
- 690
4
votes
2
answers
366
views
Can inflation extract information from black holes?
Suppose inflation were to occur for some brief period of time within the Schwarzschild radius of a black hole such that some matter which is just inside the event horizon now finds itself outside of ...
- 252
0
votes
1
answer
400
views
What is the expansion rate of space on the event horizon of a black hole?
Space expands and gravity has a negative impact on the expanxsion?
At the event horizon of a black hole time stands still.
So in expanding space we have time flowing normally. In a gravity field ...
1
vote
1
answer
84
views
Creating two universes at the event horizon of a black hole
Using the uncertainty principle involving time and energy, is it possible a universe and anti-matter universe be formed at the event horizon of a supermassive black-hole? If so, could one the anti-...
1
vote
1
answer
3k
views
What is the temperature of the event horizon?
In a discussion with my son about absolute zero, we arrived at the conclusion that the event horizon might be the place to look, as it "absorbs?" all energy, including light.
Found this in the ...
- 87
6
votes
1
answer
973
views
The arrow of time and the cosmology of a black hole interior
When solving the Einstein field equations in Schwarzschild metric for an observer falling into a black hole the radial coordinate r of the black hole and time t switch roles in the equations when r<...
- 161
1
vote
1
answer
221
views
Boundaries of Black Hole and Observable Universe
Are the boundaries of a black hole, the event horizon, similar to the boundary at the end of our observable universe?
- 111
11
votes
2
answers
984
views
Will acceleration rate of expansion of space become faster than speed of light?
From watching cosmology lectures, it seems that the space between galaxies is expanding at an accelerating rate, my question is since it is the space that is (acceleratingly expanding), the special ...
- 1,447
24
votes
4
answers
6k
views
Could a ship equipped with Alcubierre drive theoretically escape from a black hole?
Could a ship equipped with Alcubierre drive theoretically escape from a black hole?
Also, could it reach parts of the universe that are receding faster than the speed of light from us?
- 589