All Questions
112
questions
0
votes
1
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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
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;
$$\nabla\cdot\textbf{E}=0$$
$$\nabla\cdot\textbf{B}=0$$
$$\...
- 5,148
1
vote
2
answers
132
views
Do events very far away happen in a different timeline?
I am not sure how to ask this question in a concise manner so I am sure somebody out there explained it but I cannot seem to find it.
So I recently watched some videos explaining that $c$ not only ...
- 119
0
votes
1
answer
90
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Question about the norm of the four-velocity being equal to $c$
On the way to the Einstein equation we derived the four-velocity:
$$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
-2
votes
2
answers
60
views
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
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
-1
votes
2
answers
80
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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 $\...
- 21
3
votes
1
answer
106
views
How does the second postulate of special relativity imply invariance of spacetime interval?
I have trouble understanding why the second postulate of Special Relativity implies the invariance of spacetime interval $\Delta s^2=-c^2\Delta t^2+\Delta x^2+\Delta y^2+\Delta z^2$.
Suppose we have ...
- 209
-4
votes
1
answer
89
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Are length and time mathematically equivalent scales? [closed]
So, say we define a clock as measuring an electronic oscillation on a quartz atom, eg, a normal clock.
The fine structure constant is a relation between the electron mass and C. If C goes up, electron ...
- 1
1
vote
1
answer
112
views
How to show mathematical equivalence between the idea of relativistic mass and the geometric explanation of why massive objects can't reach $c$?
I've frequently seen two different explanations for why, in SR, it's impossible for an massive object to reach $c$:
As a massive object approaches $c$, its kinetic energy starts being converted to ...
- 2,327
0
votes
0
answers
24
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Does time slow down for light according to relativity? [duplicate]
According to Einstein's theory of relativity
Time slows for a individual who moves at the speed of light and time goes backward if the individual is faster than the speed of light.
So , is it that for ...
- 725
0
votes
0
answers
40
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Twin paradox symmetry in time dilation during the first leg [duplicate]
I was watching this Ted Ed video on Youtube about the twin paradox and found the explanation with the spacetime graph a bit confusing. At 3:00 in the video, they show a graph and explain how bursts ...
