All Questions
14
questions
0
votes
1
answer
76
views
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
1
vote
2
answers
78
views
Probability of a primordial black hole absorbing background radiation?
I'm thinking of the early universe when there was a lot of energetic radiation around. A primordial black hole (PBH) that would be about to evaporate completely about now, would have an initial mass ...
- 6,102
0
votes
1
answer
102
views
Trapping Hawking radiation in black holes?
I was reading this writing (https://davidwoolsey.com/AttO/AttO_blog/Entries/2020/7/13_Black_Holes_and_Transverse_Tidal_Effects%2C_a_revised_essay_on_some_thoughts.html) about considering tidal effects ...
- 2,462
1
vote
0
answers
89
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Is Hawking radiation possible for all massive objects (based on new research)? [duplicate]
So a few years ago, looking at the answer to this question the answer was no and that there needed to be an event horizon for hawking radiation to arise and that it is not purely curvature that causes ...
- 1,534
1
vote
2
answers
141
views
How are black-hole evaporations possible?
It is believed that if, $$
R \leq \frac {2Gm}{c^2} \; \;\;\;\; (1)
$$ is black hole and due to Hawking radiation it losses mass and subsequently when, $$R \geq \frac {2GM}{c^2} \;\;\;\;\;\; (2)$$ ...
- 91
0
votes
3
answers
119
views
Alternative to Dark Energy
If Black Holes consume mass and re radiate it in the form of massless photons the mass of the universe is declining. Could this explain the accelerating expansion of the universe without the ...
2
votes
2
answers
491
views
What phenomenon is Hawking radiation intended to explain?
I understand that science exists to make predictions, and that "unitarity" (the 100% total of the probabilities of all possible outcomes) is a major factor in the morale of scientists.
However, in ...
- 848
4
votes
3
answers
688
views
Does Hawking radiation assume general relativity?
Does Hawking radiation assume that general relativity works perfectly, inside black holes, or on the event horizon?
Could someone please tell me the exact statements made in describing Hawking ...
user45922
3
votes
1
answer
117
views
Can a lone black hole in a closed Universe evaporate?
If there is a closed Universe which only has a black hole in it, can that black hole evaporate? As the black hole evaporates, it gives off energy, which will eventually come back and be re-absorbed ...
- 2,467
5
votes
1
answer
116
views
Vacuum energy: black hole evaporation and cosmology - a discrepancy?
Black hole evaporation is a result of calculating the expectation value of the stress-energy tensor of the state of the vacuum in certain spacetimes and then making a plausibility argument as to the ...
- 1,083
1
vote
2
answers
186
views
Does the black hole only increase?
I don't understand this:
The more mass a Black Hole has, the more gravity it create! The more gravity it has, the more mass it can get!
With this lines, someday, all the universe will be a black ...
- 181
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
3
votes
2
answers
478
views
Does cosmological horizon grow or decrease as it radiates?
Ron Maimon in many posts claimed that cosmological horizon is like a big black hole.
Black holes decrease as they evaporate and their radius decreases as well.
So what is with a cosmological horizon?...
- 11.2k
7
votes
1
answer
385
views
Are black holes (and the universe in general) said to exhibit Ostwald's ripening?
Ostwald's ripening is a phenomenon where the surface area to volume ratio of droplets causes small particles to shrink until they disappear and for droplets above a certain volume to continuously grow....
- 21.1k