All Questions
11 questions
2
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2
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Can a body escape a black hole by being thrusted? [duplicate]
I am told many time that nothing can escape black-hole because black-holes escape velocity is more than speed of light. But we know object don't necessarily have to exceed speed of light to escape a ...
- 41
0
votes
0
answers
23
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Is it possible for a black hole singularity to interact gravitationally with other celestial bodies (if we analyze it using the concept of gravitons)? [duplicate]
It is known to all that the travelling speed of gravitons (the propagation speed of gravitational field) is not instant. So for black holes, the gravitons (the gravitational field) generated by the ...
2
votes
1
answer
98
views
How much time does it take for the gravitons generated by a black hole singularity to travel before exerting gravity forces on other celestial bodies?
It is known to all that the travelling speed of gravitons (the propagation speed of gravitational field) is not instant. So for black holes, the gravitons (the gravitational field) generated by the ...
0
votes
7
answers
422
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If light and gravity travels at the same speed then why light cant escape the gravitational pull of black holes?
Speed of gravity is infinite?
If fastest thing is light then how universe is spreading faster than the speed of light?
2
votes
0
answers
35
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How can black holes emit detectable magnetic fields and gravity if nothing can escape the event horizon? [duplicate]
How can black holes emit detectable magnetic fields and gravity if nothing can escape the event horizon?
- 439
4
votes
5
answers
642
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Is it theoretically possible to escape a classical black hole with force?
A stone being thrown from the surface must have a velocity of $11.2$ km/sec if it wants to escape Earth's gravity. However, a stone that has a constant force being applied on it need not have an ...
- 165
1
vote
2
answers
251
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How high can a light-beam (or apple) travel when pointed (thrown) out from the event horizon? [duplicate]
I am a bit confused at the idea that information cannot be sent out from behind the event horizon of a black-hole. Consider the following figure: (source This link)
An apple thrown up from the ...
- 3,443
6
votes
5
answers
458
views
Can the mass within the event horizon of a black hole interact gravitationally with the mass outside the event horizon?
If so, gravitons and their fields, unlike photons, must be able to cross the event horizon freely in both directions. If not, the observed mass of a black hole must depend only on the particles ...
- 61
0
votes
3
answers
276
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What is the reasoning behind the idea that light cannot escape from a black hole? [duplicate]
According to the definition, light cannot escape from a black hole.
How did scientists deduce that light cannot escape from a black hole?
- 181
10
votes
2
answers
626
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Speed of gravity in cosmological codes and ephemeris generation
There are few questions in Phys.SE concerning the speed of gravity, and the answers are traditionally that the speed of gravity equals to the speed of light. But in that case I have three more ...
- 547
8
votes
6
answers
9k
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Gravity on supermassive black hole's event-horizon
$M =$ black hole mass
Gravitation is about $r^{-2}$
Schwarzschild radius, $r_{\text{S}}$, is $\propto M$
So, more massive black holes have weaker gravitation at their event horizon.
Consider a black ...
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