The light produced by charged particles as light travels through a transparent medium at a speed faster than the speed of light in that medium.
Although the speed of light in a vacuum is a universal constant (c = 299,792,458 m / s), the velocity of an object can be considerably slower because it slows down the medium. For example, in water it is only 0.75C
Cherenkov radiation, when it intensifies, appears as a faint bluish-white glow in the water that protects some nuclear reactors. Cherenkov radiation is caused by electrons from the reactor traveling faster than the speed of light in water, which is about 75 percent the speed of light in a vacuum.
An active charged particle moving through a medium displaces electrons at certain atoms in its path.
Rapidly moving between water molecules
Cherangov radiation is the light emitted by these electrons
It’s like a super boom coming out of a plane moving faster than sound
Light that normally travels through a vacuum does not have that relative velocity.
The phenomenon is named after the Soviet physicist Powell Cherenkov, who shared the 1958 Nobel Prize in Physics.