All Questions
Tagged with gravity general-relativity
2,007
questions
46
votes
9
answers
12k
views
Is it theoretically possible to shield gravitational fields or waves?
Electromagnetic waves can be shielded by a perfect conductor. What about gravitational fields or waves?
- 563
6
votes
1
answer
729
views
Quantum Gravity and Calculations of Mercury's Perihelion
In an astronomy forum that I frequent, I have been having a discussion where the state of quantum gravity research came up. I claimed that Loop Quantum Gravity theories couldn't prove GR in the ...
- 1,661
9
votes
3
answers
2k
views
Why space expansion affects matter?
If space itself is expanding, then why would it have any effect on matter (separates distant galaxies)?
Space is "nothing", and if "nothing" becomes bigger "nothing" it's still a "nothing" that ...
- 1,445
1
vote
3
answers
374
views
A Question on Singularity
I am not aware of GR, but due to curiosity i have a question in my mind. Please let me know if it is inappropriate to ask here.
My question is about singularity. I am under the assumption that ...
- 2,152
4
votes
4
answers
1k
views
White Holes and Time-Reversed Oppenheimer-Snyder collapse
So, the canned explanation that I always hear about why the white hole solution of the extended Schwarzschild solution is non-physical is that "The matter distribution cuts off the white hole solution....
- 41.6k
34
votes
6
answers
5k
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Could gravity be an emergent property of nature?
Sorry if this question is naive. It is just a curiosity that I have.
Are there theoretical or experimental reasons why gravity should not be an emergent property of nature?
Assume a standard model ...
- 13.5k
0
votes
1
answer
496
views
Why do we define such a thing as singularity?
According to general relativity, an observer not in the close proximity of a black hole, observing a mass fall into that black hole, will never see that mass cross event horizon(it will gradually fade ...
- 1,688
13
votes
2
answers
5k
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Noticing that Newtonian gravity and electrostatics are equivalent, is there also a relationship between the general relativity and electrodynamics?
In classical mechanics, we had Newton's law of gravity $F \propto \frac{Mm}{r^2}$. Because of this, all laws of classical electrostatics applied to classical gravity if we assumed that all charges ...
- 6,000
492
votes
21
answers
54k
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How does gravity escape a black hole?
My understanding is that light can not escape from within a black hole (within the event horizon). I've also heard that information cannot propagate faster than the speed of light. I assume that the ...
- 5,039
5
votes
3
answers
3k
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Is it possible/correct to describe electromagnetism using curved space(-time)? [duplicate]
Comparing the simples form of the forces of both phenomena: the law of Newton for gravitation $V\propto \frac{1}{r}$, and the Coulomb law for electrostatics $V\propto \frac{1}{r}$, one might think ...
- 1,445
8
votes
7
answers
36k
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Planet orbits: what's the difference between gravity and centripetal force?
My physics teacher says that centripetal force is caused by gravity. I'm not entirely sure how this works? How can force cause another in space (ie where there's nothing).
My astronomy teacher says ...
- 6,927
20
votes
7
answers
7k
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Is Newton's Law of Gravity consistent with General Relativity?
By 'Newton's Law of Gravity', I am referring to
The magnitude of the force of gravity is proportional to the product of the mass of the two objects and inversely proportional to their distance ...
- 6,000