Cherenkov Radiation
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Cherenkov Radiation
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Re: Cherenkov Radiation
#2In water!
"In water" is the "In mice" equivalent for physics.
Re: Cherenkov Radiation
#3The title (likely intentionally) is misleading, it should say "travelling faster than light in a medium". Nothing here travels faster than light in vacuum.
BTW there are special types of telescopes used to observe gamma rays - they cannot see gamma ray directly but observe a flash of Cherenkov light of a cascade of charged particles created when gamma ray hits atoms in the atmosphere. Those telescopes are Imaging Atmospheric Cherenkov Telescopes [1].
1. https://en.wikipedia.org/wiki/MAGIC_(telescope) or https://en.wikipedia.org/wiki/VERITAS or https://en.wikipedia.org/wiki/High_Energy_Stereoscopic_Syste... or https://en.wikipedia.org/wiki/Cherenkov_Telescope_Array_Obse...
Re: Cherenkov Radiation
#4I wonder if there could be something other than vacuum, in which light would travel faster.
Re: Cherenkov Radiation
#5I wonder if there could be something other than vacuum, in which light would travel faster.
Kind of, with trickery.
https://math.ucr.edu/home/baez/physics/Relativity/SpeedOfLig...
Re: Cherenkov Radiation
#6In water! "In water" is the "In mice" equivalent for physics.
Technically it's any medium. The lower the refractive index, the closer the particle needs to travel to the speed of light in vacuum. But you can for example measure Cherenkov Radiation in the air (where n~=1.0003 or 99.97% of c) from highly energetic cosmic rays.
https://en.wikipedia.org/wiki/Imaging_atmospheric_Cherenkov_...
Re: Cherenkov Radiation
#7>
How can something travel faster than light?
> Nothing can travel faster than the speed of light in a vacuum. However, in other mediums, particles can potentially move faster than light. For instance, while in water, light would instantly slow down to 75% of its normal speed, but there are other particles that don’t slow down as much and end up moving faster than light. Whenever that happens, a blue or violet glow occurs.
After reading this answer, I was not any wiser.
Re: Cherenkov Radiation
#8I wonder if there could be something other than vacuum, in which light would travel faster.
Probably not, to get light to move faster, you don't need a new medium - you just need less of the universe getting in its way.
Re: Cherenkov Radiation
#9> When charged particles moving faster than light travel in, for example, water, they perturb the energy equilibrium of the atoms that are in their way.
Why? How good an analogy is a sonic boom?
Re: Cherenkov Radiation
#10> How can something travel faster than light? > Nothing can travel faster than the speed of light in a vacuum. However, in other mediums, particles can potentially move faster than light. For instance, while in water, light would instantly slow down to 75% of its normal speed, but there are other particles that don’t slow down as much and end up moving faster than light. Whenever that happens, a blue or violet glow o…
In water photons travel at say 200,000km a second. Neutrinos travel at nearly 300,000km a second. That’s causes a blue glow. Which is how neutrino detectors work.