April 29, 2013
What is Cherenkov radiation?
When light enters a material such a a water, it slows down by however much the index of refraction is. A particle will also slow down. However, the particle, since it can have quite a bit of energy, might not slow down to the speed of light in water. This is entirely possible since the speed of light in a vacuum is the limit. If the particle is going faster than the speed of light in water, then it will essentially create a sonic boom of light (most often, a blue light).