Scientists have just figured something out about the Jupiter moon Europa—it glows in the dark. Which, as a post at NASA points out, might not seem that weird to a layman. After all, we look up and see our own moon glowing in the night sky. But something entirely different is happening up near Jupiter, and it could help shed light on the question of whether Europa could sustain life, per NBC News. Whereas our moon glows because it reflects light from the sun, icy Europa glows because it's being bombarded by radiation from Jupiter itself. In fact, researchers speculate in their study at Nature that the moon's night side, or the side facing away from the sun, glows continuously because of this radiation. "The nighttime ice glow occurring on Europa may be very unique and unlike any other phenomenon in our solar system," per the study.
Researchers figured this out by building a model on Earth made up of ice and different salts believed to be on Europa, then blasting it with radiation. "We never imagined that we would see what we ended up seeing," says study co-author Bryana Henderson. As they altered the compositions, the glow changed. Two probes headed Jupiter's way in the coming years will now try to detect this glow, and that information could be compared with results from the study to help astronomers determine the precise chemical makeup of Europa and whether it could support life, per CNN. "Radiation in the form of electrons, protons, and ions with high-energy may also be one of the requirements for Europa's potential habitability," says NASA's Murthy Gudipati. Another key factor: Though icy on the surface, Europa might have an inner ocean of water. (Read more Europa stories.)