Cool Picture of the Day: Cherenkov Radiation

Cherenkov radiation (also spelled Cerenkov or Čerenkov) is electromagnetic radiation emitted when acharged particle (such as an electron) passes through an insulator at a constant speed greater than the speed of light in that medium. The characteristic blue glow of nuclear reactors is due to Cherenkov radiation. It is named after Russian scientist Pavel Alekseyevich Cherenkov, the 1958 Nobel Prize winner who was the first to characterise it rigorously.^{[1] - Source: Wikipedia}