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Q & A: Are there shockwaves of light like sonic booms?

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Most recent answer: 12/23/2013
Q:
if we could reach or exceed the speed of light at what point would we reach compress-ability of photons much like the sound barrier ? what would be the results as such a light flash?and as we reach or exceed light speed we are seeing generated or reflected light, would we be able to see things in the same frame of time as such we travel faster than light would it it not be reflections from the near and distant past? and one more related what we use for communications we would be there before the radio transmission ?
- Ed Bates (age 58)
Springtown TX USA
A:

Hi Ed,

I don't fully understand all of your questions, so I'll direct you to an effect which I think you are interested in, and you can follow-up if you still have questions.

As you know, traveling faster than the speed of sound in air causes a shock wave known as a sonic boom. Similarly, if a charged particle travels faster than the speed of light* in a medium, then it emits an electromagnetic wave known as Cherenkov radiation.

*Nothing can travel faster than the universal constant c, the speed of light in vacuum. But the speed (specifically, phase velocity) of light in a medium is slower, and is the speed you have to beat to get Cherenkov radiation.

This radiation is often found in nuclear reactors, which is why they look beautiful and dangerous, like this:

More about Cherenkov radiation can be found on Wikipedia:

Cheers,

David Schmid

 


(published on 12/23/2013)

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