New lab experiments re-create the environment of Europa and find that the icy moon shines, even on its nightside. The effect is more than just a cool visual.

PASADENA, Calif. (NASA PR) — As the icy, ocean-filled moon Europa  orbits Jupiter, it withstands a relentless pummeling of radiation. Jupiter zaps Europa’s surface night and day with electrons and other particles, bathing it in high-energy radiation. But as these particles pound the moon’s surface, they may also be doing something otherworldly: making Europa glow in the dark.