Saturn’s 320-mile-wide moon Enceladus sprays its interior ocean into space in this picture, a color-composite made from images taken by NASA’s Cassini spacecraft on November 30, 2010 from the moon’s night side. The original images were captured in visible light filters and the result has been subjectively adjusted for contrast and saturation. South is pointed upward in this view.Some of the icy material sprayed out falls back down to the surface of Enceladus but much of it ends up in orbit around Saturn, forming the hazy and diffuse E ring… and a small bit of that even ends up “raining” down into Saturn’s atmosphere.

Cassini’s fly-through samplings of Enceladus‘ plumes—which erupt from long fissures called sulci that gouge its southern polar region—show a salinity very similar to Earth’s oceans and researchers have found that the temperature and pH are also similar. It’s one of the most promising environments for life outside of Earth that we’ve found so far.

The Cassini mission ended in September 2017 when the spacecraft executed a planned descent into Saturn’s atmosphere, completing its impressive 13-year-long investigation of the ringed planet and its moons. Until another such dedicated mission is developed, whatever Enceladus might harbor in the ocean beneath its ice will remain a mystery.

Image credits: NASA / JPL-Caltech / SSI / Cassini Imaging Team / Jason Major