Cherenkov radiation is a type of electromagnetic radiation emitted when a charged particle, such as an electron, travels through a dielectric medium, like water or glass, at a speed greater than the speed of light in that medium. This phenomenon occurs because the particle disturbs the surrounding medium, causing it to emit light as it moves. The emitted light appears as a blue glow, which is often seen in nuclear reactors or particle detectors. Cherenkov radiation is used in various applications, including particle physics experiments and medical imaging, to help detect and analyze high-energy particles.