All Questions
Tagged with spacetime speed-of-light
190
questions
2
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1
answer
157
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When you are in a gravitational field, do object far away get physically closer to you as you get closer to the mass?
An observer A is close to a black hole and an observer B one light year away. They are both remaining at constant radial distance from the black hole. A is at 2 Rs away from the center of the black ...
- 161
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0
answers
65
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Does the holographic principle allow photons to have a reference frame?
It’s often said that photons cannot be assigned an inertial reference frame, given that doing so would contradict a foundational postulate of special relativity: the invariance of the speed of light; ...
- 7
0
votes
1
answer
54
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Proof of the invariance of $c$ using the Lorentz group
Apologies if this question was already asked a few times but i could only find proofs of the invariance of $ ds^2 $.
Is there any way of proving the 2nd postulate (that $c$ is invariant in all ...
- 309
-4
votes
2
answers
102
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Can we use the fabric of spacetime to go faster than the speed of light?
If the fabric of spacetime isn't bound by the limit of the speed of light (the universe is expanding faster than the speed of light), could humans somehow wrap a spaceship in a bubble of the fabric of ...
12
votes
5
answers
2k
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Could relativity be consistent if there are multiple light-like fields with different invariant speeds?
My understanding of real physical theory of electromagnetism goes like this:
The Maxwell equations can be used to derive the speed of light;
$$\nabla\cdot\textbf{E}=0$$
$$\nabla\cdot\textbf{B}=0$$
$$\...
- 5,148
1
vote
2
answers
132
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Do events very far away happen in a different timeline?
I am not sure how to ask this question in a concise manner so I am sure somebody out there explained it but I cannot seem to find it.
So I recently watched some videos explaining that $c$ not only ...
- 119
0
votes
1
answer
88
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Question about the norm of the four-velocity being equal to $c$
On the way to the Einstein equation we derived the four-velocity:
$$u^\mu=(c,v^k)$$ with $v^k$ being the 3-velocity, which can can be very low ($
|v|<<c$).
However, the square of the four ...
- 157
0
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1
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76
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Is it more accurate to say space in a weaker gravitational field is contracted, or that time is faster?
Little thought experiment. An observer places a mirror and a clock 1 lightyear away from a black hole. He then goes in the black hole's gravitational field at a point where he sees the clock tick at 2 ...
- 161
-2
votes
2
answers
60
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Time dilation query [closed]
In the light clocks, time ticks via the motion of light and since speed of light is constant therefore when the clock is in motion ,the photon has to cover a greater distance by the perspective of an ...
23
votes
7
answers
5k
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Is there a *geometric* explanation for why photons have no rest frame?
I've read the various threads on this site that talk about it being impossible for photons (or massless particles in general, really) to have a rest frame, and the answers all seem to boil down to &...
- 2,327
2
votes
1
answer
776
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The value of speed of light in different regions of spacetime
This question of mine started shaping in my head first while I was looking for the most fundamental answer for the speed of light's value and its property of being the limit.
I have convinced myself ...
- 23
0
votes
6
answers
218
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Speed of Light and Time [closed]
I'm an amateur and this is my first question here, I'm trying to formulate question about a general representation I have in mind after trying to grasp the idea of relativity and the concept of space-...
- 143
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2
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79
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Question on Special Relativity regarding light [duplicate]
Mine is a very basic question yet I haven't got a satisfactory answer so I turn to you. Special Relativity is based on two assumptions, one of which is that the speed of light is constant for all ...
0
votes
1
answer
67
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Can we observe a more recent space?
The space we are viewing now is their distant past as their light has only reached our eye or telescope after travelling a long distance at the speed of light. However, for lights that are still on ...
2
votes
0
answers
179
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An interpretation of special relativity? [closed]
Consider a 4-dimensional space $\mathrm{S}$ in which all objects move at the same speed $c_S$ but in different directions. For the objects A and B that move in directions $\overrightarrow{u_A}$ and $\...
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