All Questions
Tagged with black-holes cosmology
38
questions with no upvoted or accepted answers
4
votes
1
answer
405
views
Is Poplawski's "Cosmology with torsion" a "variable speed of light" cosmology?
In his 2010 paper "Cosmology with torsion", Poplawski mentions that, in the hypothesized formation of a new temporally-local universe within a black hole, its "expansion is not visible for observers ...
- 848
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
3
votes
0
answers
129
views
Black hole vs Dark energy
This is a follow-up question to this answer.
The original question was whether there is a maximum size limit to a black hole in our universe. The answer given was that if the event horizon coincided ...
- 9,500
3
votes
0
answers
64
views
Cosmology from within a black hole
Suppose an astronaut is travelling "into" a black hole and has already passed the Schwarzschild boundary (as described in this video). What will the universe look like to this astronaut, ...
- 131
3
votes
0
answers
126
views
Evolution of black holes ensemble
Background:
I’ve read many times that arrow of time can be explained from extremely low entropy of the Universe at the Big Bang (http://preposterousuniverse.com/eternitytohere/faq.html). The argument ...
- 69
2
votes
0
answers
40
views
Calculating Gaussian Curvature for metric
I am trying to calculate Gaussian curvature of an optical metric
$$
d \sigma^2=\frac{r\left(\omega_{\infty}^2-\omega_e^2\right)+2 m \omega_e^2}{(r-2 m) \omega_{\infty}^2}\left(\frac{d r^2}{1-\frac{2 m}...
- 21
2
votes
0
answers
61
views
Gravitational deflection of light and the second Friedmann equation
Is the fact that light bends twice as much as matter does in Schwarzschildian gravitational fields related to the implication of the second Friedmann equation (in which $\ddot{a}\propto\rho + 3p$, ...
- 41
2
votes
0
answers
104
views
Supertranslations & Superrotations and black holes
I am currently (attempting to) the black hole memory effect and I am really struggling to find introductory explanations which simply state ��this is what is meant by a supertranslation on a black hole ...
- 21
2
votes
0
answers
98
views
What's the difference, if any, between Soft Hair & Quantum Hair
In the early 90s, John Preskill, Sidney Coleman, Frank Wilzcek and Lawrence Krauss presented a series of papers [1][2][3] on Quantum Hair on Black Holes due to Cosmic strings in a number of ways ...
- 425
2
votes
0
answers
101
views
Statistics of Black Holes
I am hoping to collect information about the sampling distribution of black hole sizes, densities, and their relative spatial distribution within galaxies and other formations. By sampling ...
- 397
2
votes
0
answers
174
views
Modelling a matter dominated universe collapsing into a black hole
With the FLRW equations we can get solutions for a matter dominated closed universe in which the finale is an ultimate collapse, but this is only in terms of $a$ (the scale factor) and $t$ (time) and ...
- 321
2
votes
1
answer
61
views
Does the Bekenstein entropy bound present problems for unitarity in cosmological models that invovle a collapse or bounce?
If we expect the Bekenstein bound, or something like it, to hold in a collapsing universe, will that not eventually force us to accept some loss of information, or is there something I'm missing?
- 31
1
vote
0
answers
55
views
Angular momentum, black holes and up-tunneling events in the vacuum
To give some context on the matter, I found these interesting articles (https://arxiv.org/abs/2007.11428 & https://arxiv.org/abs/2003.04927) where the authors analyzed, among other things, the ...
- 2,462
1
vote
0
answers
23
views
In the Steinhardt's bouncing cosmology, how would the CMB differ for patches close to pre-existing black holes
In Steinhardt's bouncing cosmology model, during the contraction phase the Hubble radius shrinks to microscopic sizes, although the overall contraction of the universe is much less significant. Each ...
- 11
1
vote
0
answers
91
views
If all the black holes in the Universe were combined into one supermassive black hole, what would its diameter be?
I am curious to know if anyone has ever sat down and calculated what the diameter of a black hole would be, in kilometers, if it were to contain all the mass of all the black holes that are currently ...
- 478