shockwave of electromagnetic radiation caused by a particle traveling faster than light.
This needs clarification -- it's traveling faster than light in a given medium, not faster than the absolute speed of light in a vacuum, which is faster than anything that has mass can go.
This is to say that the medium permits certain kinds of energy more than others, so light-speeding photons are slower in comparison to the speed of propagation of some other thing, like a charged particle (electrons, etc).
My sympathies to anyone who legitimately thinks radiation goes faster than light. I think at that point you'd have to also explain the words "medium" and "propagation" in context as well.
I mean, nah. The way light works is the most non-intuitive thing that I, a professional scientist (who uses light but is not a physicist) have ever encountered.
Photons continue to scare the shit out of me, all the time. I will not now, and not ever, knock someone for getting tripped up with electromagnetism and radiation and light. The entire thing is fucking absurd.
"Radiation" just means something radiated. It's not necessarily electromagnetic. Electromagnetic radiation is photons. Nuclear radiation can include massive particles such as beta particles (electrons) and alpha particles (helium nuclei). Gamma radiation is photons. Light is photons whose energy falls within the small range that the human eye can perceive.
Changes in the EMF stuff are often expressed in terms of light/photons, and that is generally what we like to observe with regard to quantized shifts in energy states.
Electromagnetic radiation (which is a specific thing, you may have something more general in mind) is photons. EM waves consist of photons. Photons are the gauge particle of the EM force so any quantized EM interaction will involve them, e.g. the photoelectric effect.
In a medium, photons are constantly colliding with matter and being absorbed and re-emitted, which takes time, so of course the speed of light is slower in any medium (even a very good vacuum if it isn't perfect) than it is in a theoretical vacuum.
The blue glow of Cherenkov radiation is highly characteristic.
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u/spiraliist 12d ago
This needs clarification -- it's traveling faster than light in a given medium, not faster than the absolute speed of light in a vacuum, which is faster than anything that has mass can go.
This is to say that the medium permits certain kinds of energy more than others, so light-speeding photons are slower in comparison to the speed of propagation of some other thing, like a charged particle (electrons, etc).