The scars of Europa’s chaos terrain also includes simple table salt, which could inform scientists about the nature of the moon’s underground ocean. (Credit: NASA/JPL-Caltech)

Scientists are fairly confident that Jupiter’s moon Europa has an underground ocean, even though they’ve never seen it.

Hidden beneath an icy crust, most of what researchers know about that ocean is based on the moon’s smooth, streaked surface. Europa lacks mountains or large craters, but it is crisscrossed with ri