All Questions
15
questions
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Has this random youtube crackpot trying to disprove GR inadvertedly stumbled on a genuine prediction of it? [duplicate]
I'm an Astrophysics major. I was watching strange fringe physics crackpots on Youtube to make fun of them, because I'm an acollierastro, planarwalk kinda gal. I came across this guy who thinks Black ...
1
vote
0
answers
95
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Black Holes, Gravity, and the Creation [duplicate]
As I suppose we all accept, the universe started as an unintuitive singularity—either, "Let there be light," or "The Big Bang". Something from nothing expanded and at luminal ...
- 111
8
votes
3
answers
2k
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Primordial black hole vs. black hole
Are there sharp distinctions between primordial black holes and the usual black hole?
Can a primordial black hole smoothly become massive to be a black hole?
Can a black hole smoothly become less ...
- 4,336
1
vote
1
answer
225
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How to calculate the strength ("space force") of dark matter within galaxies?
Let's first have a look at the observed speed within galaxies (source):
On the left side we can see the speed of celestial bodies within galaxies derived by gravity only (gravity is usually created ...
- 282
0
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0
answers
68
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The relation between the weak gravity conjecture and wormholes
Charged black holes are usually associated with the weak gravity conjecture at extremal limit, according to the well-known relation, i.e. charge to mass ratio. Now my question is that how the weak ...
user212754
0
votes
2
answers
858
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Will everything eventually be a single black hole? [duplicate]
Given the idea that gravity is always a factor (even though greater distances are excessively tiny), would everything eventually end up forming a single black hole?
My thinking is that, with infinite ...
- 1,083
4
votes
1
answer
3k
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If the Big Bang theory is true, what caused it to explode?
According to the Big Bang theory, all the matter in the universe was amassed together at one single point. If this was the case, why was it able to explode? The density of the mass would create a ...
- 83
1
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0
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238
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In what sense is ''Oppenheimer-Snyder collapse a time reversed closed FRW model"?
In what sense is ''Oppenheimer-Snyder collapse a time reversed closed FRW model" ?
That is, "Are closed FRW metric (k=1) and the geometry inside the collapsing homogeneous matter same?" If yes, how? ...
2
votes
1
answer
169
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Universe expansion / contraction ambiguity
I've read everywhere that the universe is expanding, and accelerating the expansion. But it is our single point observations of the universe enough to resolve this result?
What gives us 100% ...
- 133
1
vote
2
answers
194
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Could the universe be shrinking? [duplicate]
It is thought the universe is expanding because of the red shift of most galaxies but if all the matter in the universe was actually falling into a massive black hole wouldn't most galaxies still be ...
0
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2
answers
174
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Universe Expanding
Quick question that I was just hoping to get some clarification on. Current theories state that the universe is expanding; with those planets farther away moving away from us at a faster rate.
Is it ...
- 31
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0
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86
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Evidence of possible tidal effects close to a gravitational wave emitting system
Currently we are attempting to detect gravitational wave emissions using the LIGO gravitational wave detection system (and similiar systems), by attempting to detect very weak gravitational waves ...
user81619
1
vote
4
answers
1k
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Could black holes be driving the expanding universe (dark energy)?
I would like to start be saying I'm no Physicist.
Anyway, my question is: Could black holes be driving the expanding universe (dark energy)?
When I think of the image that the effect of massive ...
- 19
1
vote
1
answer
70
views
Supermassive Black holes at centers of galaxies [duplicate]
Why there is super-massive black holes at the center of our galaxy and other galaxies ?
- 495
0
votes
5
answers
1k
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What generates such a huge amount of gravitational attraction in a black hole?
I had been fascinated to hear that anything can be swallowed by a black hole. But what causes such a huge amount of gravitational force?
- 241