All Questions
13
questions
0
votes
1
answer
51
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Speed in a medium
Let's say, that there is medium, where the speed of light is $10^8 \, \rm m/s$. So in that medium if there exists a particle that is moving through without any hindrance what would be the speed limit ...
- 151
1
vote
1
answer
351
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Amaterasu particle's secondary particles travel faster than the speed of light?
From this article in The Guardian
When ultra-high-energy cosmic rays hit Earth’s atmosphere, they initiate a cascade of secondary particles and electromagnetic radiation in what is known as an ...
- 119
4
votes
5
answers
488
views
Is the speed of causality slower in water?
I've recently read that what most people learned to think of as the 'speed of light' is actually the 'speed of causality', and that light just happens to travel at that speed (through free-space.) I'...
- 453
0
votes
1
answer
63
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Cherenkov radiation; hypothetical question
It is explained that Cherenkov radiation is light that emit a particle inside a refractive material when the speed of the emitted light is slower than $c$. So my hypothetical question is what would be ...
- 2,255
3
votes
3
answers
1k
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Can an object move faster than the speed of light in a medium? [duplicate]
In water the speed of light changes to $2.25 \cdot 10^8m/s$. Can a electron travel faster/travel at the same speed in water. I don't see any violation of SR. So shouldn't it be possible for an ...
- 1,333
1
vote
0
answers
190
views
Is the speed of light universal for all mediums? [duplicate]
We know that the speed of light is constant in a vacuum and has the value c= 3× 10^8 m/s.
But in a medium such as glass(refractive index=1.5) the speed of light is 2× 10^8 m/s. Now considering the ...
- 141
-1
votes
3
answers
630
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What is Cherenkov radiation? [duplicate]
What is Cherenkov radiation? I came across this concept when I was learning SR.
Why can't particles moving at speed of excess of speed of light in the medium. Why it does not violate the limitation ...
user221098
2
votes
1
answer
237
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Could we travel faster than the speed of light in a medium, but slower than the speed of light in vacuum? [duplicate]
It is well accepted that nothing with mass can travel at the speed of light in vacuum, $c$. Now let's say that a light wave is traveling through a medium that slows the wave's speed significantly (...
- 163
0
votes
1
answer
180
views
Can something go faster than the speed of light in a medium? [duplicate]
Since some mediums have an index of refraction more than 1, light goes slower than in a vacuum. Does this mean it is possible for particles to go faster than the speed of light in these mediums? If so,...
- 691
25
votes
3
answers
8k
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How can muons travel faster than light through ice?
When a neutrino traveling through ice hits and interacts with an oxygen atom, muons are created.
Cherenkov radiation can be created when muons travel through ice faster than light and create a ...
- 3,348
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
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
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