Cerenkov radiation

Cerenkov radiation occurs when a charged particle, such as an electron, travels through a medium (like water or glass) faster than the speed of light in that medium. Although nothing can exceed the speed of light in a vacuum, light moves slower in substances due to interactions with their molecules. As the particle moves, it disturbs the surrounding medium, causing it to emit a visible blue light, which is Cerenkov radiation. This phenomenon is used in various fields, including nuclear reactors and medical imaging, to detect high-energy particles.