All Questions
Tagged with black-holes cosmology
215
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How can black holes possibly drive accelerating expansion of the universe?
(Potentially too broad, but all my questions are related to the paper in question.)
Recently there was an article published in Astrophysical Journal Letters that claims black holes "contribute ...
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What portion of the universe is black holes?
What portion of the universe is black holes? Is it possible to estimate the percent of all mass that is in the black holes?
- 605
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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
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Why didnt early universe collapse into black hole? [duplicate]
Given the early universe was infinitely small, why didnt it immediately collapse into a blackhole before it had time to expand?
- 11
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Why is a primordial black hole's mass of the same order as the horizon mass in the early universe?
I am reading a paper on primordial black holes (PBHs), and it says that PBHs should form during the first second of the universe with masses of the same order of magnitude as the horizon mass.
I ...
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2
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Does the rate of expansion of the universe depend on the mass or size of the galaxies?
Does the rate of expansion of the universe depend on the mass or size of the galaxies? How constant dark energy density affect the massive/lighter galaxies?
- 91
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Could heat death be avoided in cosmology?
I found this old article by Steven Frautschi 1 which talks about avoiding heat death by a hypothetical advanced civilization able to group Black Holes in clusters. He writes that in this way, the ...
- 2,462
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We say the big bang (initial singularity) didn't happen at a point, but is it the same with the singularity of a black hole?
I have read this question:
The simple answer is that no, the Big Bang did not happen at a point. Instead, it happened everywhere in the universe at the same time. Consequences of this include
The ...
- 29k
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Are there Black Holes that do not have global time-like killing vector fields?
Can there be any Black Holes that do not have global timelike Killing vectors? And if there can be such Black Holes, does the conservation of energy apply to them? Can there be Black Holes with a non-...
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3
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190
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Degree of time dilation for stars orbiting near Sagittarius A*? [closed]
Sagittarius A* has an estimated mass of 4.154 million solar masses. A number of stars have been found to orbit near Sagittarius A*.
What is the maximum time dilation factor for any of these orbiting ...
- 173
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How can the ratio of a black hole's (or any object's) angular momentum to its mass be less than one?
In the latest Quanta Magazine article, about Kerr black holes, the researchers say their new solution for these objects only works, so far, for Kerr black holes with a ratio of angular-momentum-to-...
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Could black holes be the reason for the expanding of the universe?
I would like to start be saying I'm no Physicist.
I was wondering if known and mostly unknown black holes could be the reason for the "expanding" of the universe.
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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 ...
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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
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Conformal cyclic cosmology, black hole and Weyl curvature
Roger penrose in his theory "conformal cyclic cosmology" states that after a google there would be a giant black hole. Does black hole have Weyl curvature? If it does, then we know that ...
