Introduction to Cherenkov Radiation

           It is well known that the speed of light represents the upper limit of velocity for all energy and matter in the universe. However, the speed at which light travels     changes between mediums, for a vacuum it measures c, or roughly 3x10^8 m/s. In another medium, such as water, the speed of light can be significantly slower.         Now, it is possible to accelerate a particle through a medium faster than the speed of light in that medium. When this is done the molecules in that medium are             excited, and when returning to their ground state they emit radiation.

Sean Lemley Physics 212X F05.