THIS is what happens when matter goes faster than light speed. It’s not just some blue light. You’re watching Cherenkov Radiation take place. In water, light travels slower, and when charged particles move faster, they leave behind this cool blue echo of light. 💡 For more cool science like this, catch up on episodes of @okaytobesmart on YouTube! | PBS Digital Studios

Nuclear reactor startup ☢️ The blue glow is a classic example of Cherenkov radiation, which occurs when a charged particle passes through a dielectric medium at a speed greater than the phase velocity of light in that medium. Follow @betaeq | Beta EQ

What’s that blue glow surrounding a reactor? It’s a phenomenon known as Cherenkov Radiation when electrically charged particles, such as protons or electrons, travel faster than light in a clear medium like water. | U.S. Department of Energy Office of Nuclear Energy