All Questions
13
questions
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How is special relativity explained by general relativity?
To be more specific about this, I am under the below assumptions and then will explain my question further. Please let me know if any of the assumptions are incorrect.
(1) Special relativity describes ...
2
votes
3
answers
142
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What does it physically mean for the inverse of the metric tensor of inertial frames to be the metric tensor itself?
The metric tensor of inertial frames in S.R is given by $$g_{\alpha \beta}=diag(1,-1,-1,-1)$$
It's inverse $$(g_{\alpha \beta})^{-1}=g_{\alpha \beta}$$
I was wondering what this means geometrically. I ...
- 223
6
votes
2
answers
750
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Can a Kerr black hole be viewed as a Schwarzschild black hole by changing the frame of reference?
In a local universe empty of any matter except a Kerr black hole and an observer, that observer is spinning at the same rate as the black hole and observes it from a great distance directly above its ...
- 643
1
vote
1
answer
101
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Why is a falling observer inertial, in general reletivity, when momentum cannot be conserved in this frame?
TL;DL
In an inertial frame of reference, one fundamental law that always holds is the conservation of momentum. If you take the reference frame of one of the interacting objects the conservation of ...
- 775
5
votes
4
answers
2k
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General Relativity: Definition of Locally Inertial Frame
The Einstein Equivalence Principle states that in a sufficiently small frame of reference is impossible to know if we are into a gravitational field or not. Equivalently we cannot say if we are in an ...
- 4,577
0
votes
2
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239
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Absolute Space & Inertial Frames
When we solve the twin paradox we say something like the traveling twin has a Rindler Metric while the stationary twin has a Minkowski metric, or more plainly, the traveling twin experiences non-zero ...
- 749
2
votes
3
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727
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What makes the Earth accelerate in a free-falling object's frame of reference?
If I'm an object in free fall near earth, then I'm an inertial frame of reference and I see the earth accelerating towards me with no force acting upon it. What causes that acceleration? The spacetime ...
2
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0
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62
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About General Relativity and Reference Frames
So, I came up with this question which is intriguing me since a bit. Maybe it's stupid, but it's always better to ask.
The question is about inertial reference frames (I'll name them IRF)
We know ...
- 3,705
-1
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2
answers
166
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Minkowski geometry definition
The general relativity is based on Minkowski geometry definition with its special properties. The general relativity cant be approved wihout Minkowski geometry definition. Why Minkowski geometry is "...
0
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0
answers
273
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Light cones and reference frames
I'd like to know what does it mean exactly to find a reference frame in which two events occur at the same time or in the same space coordinates. As I picture it if we have two events A and B in a (x, ...
- 590
14
votes
5
answers
3k
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The definition of an inertial reference frame in Einstein's relativity
I'm reading Sean Carroll's book on general relativity, and I have a question about the definition of an inertial reference frame. In the first chapter that's dedicated to special relativity, the ...
- 1,056
3
votes
1
answer
1k
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Problem with convergent geodesics at 2D sphere
There is a chapter on general relativity in the book Spacetime Physics Introduction To Special Relativity by Taylor and Wheeler, which qualitatively explains how attractive gravitational force can be ...
- 2,163
6
votes
2
answers
4k
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Can an "absolute" frame of reference be determined by measuring the compression of light?
General relativity tells us that there is no absolute frame of reference (actually, it tells us that all frames are relative, which is close but not the same as there is no absolute frame).
Special ...
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