All Questions
Tagged with refraction special-relativity
68
questions
41
votes
5
answers
13k
views
Is light actually faster than what our present measurements tell us?
It is well established that the light speed in a perfect vacuum is roughly $3\times 10^8 \:\rm m/s$. But it is also known that outer space is not a perfect vacuum, but a hard vacuum. So, is the speed ...
user182521
16
votes
2
answers
2k
views
What happens if light/particles exceeded the speed of light for a particular medium?
While the speed of light in vacuum is a universal constant ($c$), the speed at which light propagates in other materials/mediums may be less than $c$. This is obviously suggested by the fact that ...
- 1,187
12
votes
2
answers
5k
views
Deriving the law of reflection for a moving mirror in relativity
I am following a training course and came across this proof, from my colleague, that the ordinary law of reflection $\theta_i = \theta_r$ does not hold in relativity:
Let $S$ be a perfectly ...
- 2,547
11
votes
2
answers
2k
views
Do photons age in a medium?
According to special relativity, time starts to slow down as we increase our speed and eventually stops once we get to the speed of light. By that logic, photons don't age in a vacuum state as, to us, ...
user34284
10
votes
6
answers
3k
views
Lorentz invariance of Maxwell's equations in matter
I know that Maxwell's equations of electromagnetism are Lorentz invariant in a vacuum. But what about in a generalized medium, e.g. a metal, a rubber, a dielectric, a magnet? I have read it comes down ...
- 1,087
9
votes
3
answers
294
views
Alongside a light ray (in another medium)
It is a said fact that the speed of light is insurmountable. But can the validity of this fact be questioned in another medium?
If I pass a beam of light in, say water (here the light speed is ...
- 1,630
8
votes
2
answers
718
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Special Relativity, refractive index and catching up with a wave
Einstein was partially motivated by the following: With Maxwell's equations, a plane wave is a sinusoidal wave that varies in space in time and moving with speed $c$. These variations are linked by ...
- 3,856
7
votes
3
answers
2k
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Is the speed of light through a medium invariant, just like the speed of light through vacuum is invariant? Also, do time dilation etc. still occur?
So, we know the speed of light through a vacuum is $c$.
Let us say that both our observers are moving past each other at speed $v$ in a medium in which the speed of light is $c'$.
So, does the usual ...
- 4,476
6
votes
2
answers
3k
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Refractive index of dielectric in different frames of reference
The setup
A transparent isotropic dielectric medium moving in the negative $x'$ direction at speed $v$ in frame $S'$ is stationary in frame $S$, where it has refractive index $n$. In other words, ...
- 6,425
5
votes
5
answers
2k
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How is it possible for the wavelength of light to change in a medium?
So my physics class has just finished a long unit on optics while at the same time I've been trying to teach myself relativity. I admit my understanding is probably rudimentary, but I figured all the ...
- 51
4
votes
1
answer
594
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Theoretically if you passed the speed of light in a medium, would there be a sonic boom equivalent?
I know that it is technically impossible to reach the speed of light in vacuum since the mass of the object travelling would reach infinity. However in a medium, would there be some sort of ...
- 151
4
votes
3
answers
5k
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How can the speed of light change in the medium when we know that it is always equal to $c$? [duplicate]
How can the speed of light change in the medium when we know that it is always equal to $c$? If we say the speed of light is changing in the medium, it will contradict the Einstein's law of special ...
4
votes
3
answers
1k
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Is it true that all particles that have a speed less than the speed of light must also have mass?
I've previously learned that massive particles cannot achieve the speed of light.
But recently I read that, concerning the gels that refract and bounce light within around enough that it can travel ...
- 376
4
votes
3
answers
758
views
Speed of light in a medium in different frames of reference
Relativity states that speed of light in a vacuum is the same regardless of the observer. Does the same hold if the light is travelling through a medium?
- 43
4
votes
1
answer
140
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What do you 'see' if you are stationary relative to a photon in a refractive medium?
A particle with zero rest energy/mass must always be at $c$ in all referentials, even why, if you could get to its referential it would have zero total energy, effectively not existing in that ...
- 223