On a moon that should be utterly dark, laboratory science suggests something quietly extraordinary: Jupiter's own destructive radiation may cause Europa's frozen night side to glow in faint greens, blues, and whites, each hue a fingerprint of the salts locked within the ice. Researchers at NASA's Jet Propulsion Laboratory recreated Europa's frigid surface conditions, bombarded salt-laced ice with high-energy electrons, and watched it emit visible light through a process requiring no sun, no atmosphere, and no heat. The colors are not mere spectacle — they may function as a remote chemical map