Cerenkov effect

The Cerenkov effect occurs when charged particles, like electrons, travel through a transparent medium (such as water or glass) faster than light can move through that same medium. Although nothing can travel faster than light in a vacuum, in materials, light slows down. When a particle exceeds this "speed of light" in the medium, it emits a faint, blue glow called Cerenkov radiation. This phenomenon is similar to a sonic boom caused by supersonic jets but with light waves, producing a distinctive glow often seen in nuclear reactors or particle detectors.