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Author Topic: Are any materials faster than light?  (Read 1098 times)

Offline thedoc

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Are any materials faster than light?
« on: 28/09/2015 19:50:01 »
Joey Kanyi asked the Naked Scientists:
   
Which material is faster than light?
What do you think?
« Last Edit: 28/09/2015 19:50:01 by _system »


 

Offline chiralSPO

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Re: Are any materials faster than light?
« Reply #1 on: 28/09/2015 21:15:17 »
Nothing with mass can move faster than light does in a vacuum.

One can shoot particles with non-zero mass at really high speeds through a medium like water, where they can have speeds greater than the speed of light in that medium (https://en.wikipedia.org/wiki/Cherenkov_radiation)

Particles can also tunnel and "instantaneously" be in one place and then the other, but it didn't actually move from point A to point B, the distances over which this happens are almost always significantly shorter than the width of a human hair, and no information can be transmitted this way (as far as we know) so don't get your hopes up. (https://en.wikipedia.org/wiki/Quantum_tunnelling)
 

Offline evan_au

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Re: Are any materials faster than light?
« Reply #2 on: 28/09/2015 22:09:55 »
There are some materials, where if you carefully prepare them, and inject light of just the right frequency, will slow down the propagation of light to a walking pace (and even stop it).

So, you could outrun light traveling through such a material!

But the speed of light as a speed limit only applies to light traveling in a vacuum.

(There are some theoretical particles called "Tachyons" which only move faster than the speed of light, but there is no solid evidence for them at this point in time.)
 

Offline mathew_orman

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Re: Are any materials faster than light?
« Reply #3 on: 29/09/2015 08:54:37 »
Again, it is not possible to slow down a photon or electromagnetic wave...
Life of a photon ends when it intersect an atomic structure...
Experiments showing assumed slow down of a photon are noting else but an acousto-optic phenomena of moving light emission spot or source... 
Visible spectrum photon would be invisible if slowed down...
« Last Edit: 29/09/2015 08:56:30 by mathew_orman »
 

Offline PmbPhy

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Re: Are any materials faster than light?
« Reply #4 on: 29/09/2015 10:42:58 »
Quote from: Aquarius
there is no such thing as a vacuum in space,
That's not quite correct. You're thinking that a vacuum is a region of space which has literally nothing in it. That's not what physicists mean when they speak of a vacuum. We think of regions of space which has no atoms in it. That's different than what you said.

Quote from: Aquarius
Photons are force carriers spinning pole over pole.
That's not what a photon is. It doesn't even make a hell of a lot of sense either.
 

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Re: Are any materials faster than light?
« Reply #4 on: 29/09/2015 10:42:58 »

 

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