Galaxies on Instagram: "When a nuclear reactor first powers on, it glows with an otherworldly blue light, one of the rarest sights on Earth. That glow is called Cherenkov radiation, a phenomenon that occurs when charged particles travel through water faster than light can move in that same medium. It’s not the light of fire, but of pure energy breaking a physical boundary. First discovered in 1934 by Russian physicist Pavel Cherenkov, the effect was later explained by Ilya Frank and Igor Tamm, e