All Questions
20
questions
0
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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
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
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
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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
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 ...
0
votes
1
answer
131
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Relativistic Mass Relative to a Stationary Observer
I know what you’re thinking, “Not another question on Relativistic Mass.” I’ve spent the better part of a day going down the general and special relativity rabbit holes, and I can not find where this ...
-1
votes
1
answer
112
views
What speed of light means? [closed]
speed of light means moving through space with the same speed you move through time?
or to move "only" through space and not through time?
Does this mean that you exist in two (or more) ...
- 77
-4
votes
1
answer
195
views
Lorentz transformation equations: an insight [closed]
Let Bob be moving towards the positive $x$-axis and Alice be stationary at the origin. Then the Lorentz transformation gives:
$$t' = \gamma\left( t- \frac{v x}{c^2}\right)$$
where $t'$ is the time of ...
- 306
7
votes
6
answers
7k
views
If you travel on car with nearly the speed of light and turn on the car headlights: will it shine in gamma light instead of visible light?
If you travel on car with nearly the speed of light and turn on the car headlights: will it shine in gamma light instead of visible light?
- 768
-5
votes
1
answer
209
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Is This Why the Speed of Light is Universally Invariant?
Please could you tell me if the following is an original thought or whether this is already understood. I ask because I am undertaking a piece of writing on the nature of spacetime. What I discuss ...
- 129
0
votes
1
answer
464
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Can a frame of reference travel with the speed of light? [duplicate]
I read that nothing with mass can travel at the speed of light. Therefor one can not ask what happens when an observer in a car moves with the speed of light. But, is it possible for a frame of ...
- 131
0
votes
2
answers
51
views
Spacetime in photon frame [duplicate]
The time-axis and the space-axis overlap for a photon's world line. Does it mean that photon has no "past" or "future" but only "present" and no "there" but ...
- 199
0
votes
3
answers
1k
views
Why are the coordinate axes of a moving frame $K'$ tilted in spacetime diagrams?
I am currently trying to self-teach special relativity (if relevant, I am still in school). I think that I already have a good intuitive understanding of, for example, time dilation and length ...
- 3,778
1
vote
0
answers
74
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Which postulates did Einstein really use in his 1905 derivation of the Lorentz transformations? [closed]
Einstein explicitly states in "Zur Elektrodynamik bewegter Körper" that the only two postulates he requires for his derivation of the Lorentz transformations are 1) the principle of ...
- 111
2
votes
7
answers
2k
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Contradictions of explanations for the speed of light [closed]
I've recently started reading the book Biocentrism, by Robert Lanza and Bob Berman, which in its mind-blowing chapters, discusses the perceptions of reality, space, and time. Lanza states that:
If ...
