All Questions
589
questions
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When is the Weyl tensor applied on null vectors a null vector?
Let $C^{\rho}_{~\alpha \beta \gamma}$ be the Weyl tensor of a spacetime $(M,g)$, that is a solution to Einstein's equation. Let $X^\alpha, Y^\alpha, Z^\alpha$ be null vector fields, i.e. $X_\alpha X^\...
- 384
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2
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158
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Does a straight line in flat space become a geodesic in curved space when the space becomes curved?
Flexible foam has shortest path from Point-A to Point-B. When the foam is not curved (space-time is not curved), the shortest path is Path-1 (straight line - before curving the foam). But if the foam ...
- 1
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2
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188
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Curvature of space in a black hole
This is a very simplistic view from an interested structural design engineer (retired).
Mass curves space. Taking the case of a sphere of uniform density the point at which you have as much mass ...
4
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3
answers
639
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Could a person weigh so much as to cause gravitational lensing?
I'm a bit familiar with the concept of gravitational lensing. I also believe that all objects have some gravitational force, even if it's minuscule.
Would an object as massive as a person cause any ...
- 589
1
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0
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46
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Has the curvature of space from GR ever been validated? [duplicate]
It is my understanding that at low gravitational potentials like we experience on earth that the time curvature dominates and that the curvature of space only becomes relevant within stronger ...
- 319
7
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5
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2k
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Why do we say gravity curves space but the other forces don't?
I'm generally aware that there have been attempts to describe things like magnetism and the other forces geometrically, like with gravity, and that QFTs have essentially supplanted them. But it's also ...
- 450
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1
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120
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Stress-energy tensor in different reference frames and spacetime curvature
The components of the stress-energy tensor are different in different reference frames. Also there is no universal time, so values of energy will be different in different reference frames.
Via the ...
- 65
0
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0
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81
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Why fully does the curvature of Spacetime cause gravity? [duplicate]
I´m already quite familiar with concepts of spacetime curvature and have heard of the metaphor of two men walking north on the Earth appearing to gravitate towards one another as they approach the ...
- 55
5
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1
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549
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Lagrange Points in General Relativity
In the Newtonian formulation of celestial mechanics it makes sense that a Lagrange point is a point where two gravitational forces of two bodies (and the centrifugal force of the rotating reference ...
- 648
-3
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1
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832
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The ‘fabric’ of space is what exactly? [duplicate]
If gravity is mass bending space time, doesn’t a ‘fabric of space’ or some other foundational structure have to exist to be bent in the first place? Why would light travel along a bend in space if ...
- 13
2
votes
2
answers
97
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Is it possible for a Ricci-flat manifold to have a negative energy measured by distant observers?
Supposing that there is a stationary sphere made of regular matters, the external spacetime geometry can be described by the Schwarzschild metric, which describes a spacetime with vanishing Ricci ...
- 1,455
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2
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80
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Would bending of spacetime make tides an invisible effect? [closed]
Similar to this question: How does general relativity explain tides?
But I’m specifically interested in if General Theory of Relativity would predict that bending spacetime means the water and land on ...
0
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1
answer
94
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How does spacetime curvature explain why it is easier to go downhill than uphill?
Gravity is spacetime curvature. Without mixing Newton's view of gravity, how does a purely spacetime curvature view of gravity explain why it is easier to bike downhill than uphill or why did the ...
- 756
0
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2
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98
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Is my shallow understanding of spacetime curvature effect correct?
in this description of spacetime curvature:
as far as i understand, and in contradiction with what I've seen online, this doesn't change the path of the apple, it rather shows the earth accelerating ...
- 25
1
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73
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Does the space curvature want it to become flat?
I've read that mass bends the fabric of space. So does space want this curvature to become flat? I know it's a different question. but I think some systems still want to come back to normal.
Does this ...
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