Enceladus, a small moon of Saturn, shows remarkable activity for its size and likely possesses an ocean. Notably, a series of subparallel ridges at the south pole were seen by NASA’s Cassini spacecraft to be venting copious water-rich plumes into space. How these plumes originate and what geochemical processes was the water subjected to before eruption are currently uncertain, and Cassini could only see and sniff (via mass spectrometry) Enceladus from the outside.
Glein and Waite  perform a new geochemical analysis of the plumes, finding a most consistent result that has the originating water interacting directly with silicates in the core. Water dancing with rocks is a common theme for astrobiology, so these results further support the notion that Enceladus might harbor life beyond the Earth. The signature for biology could also be erupted with the waters. Therefore, future spacecraft that would fly though the plumes with instruments tuned for life could find supporting evidence without the bother of having to dig into the subsurface.
Citation: Glein, C. R., & Waite, J. H. . The carbonate geochemistry of Enceladus’ ocean. Geophysical Research Letters, 47, e2019GL085885. https://doi.org/10.1029/2019GL085885
—Andrew Dombard, Editor, Geophysical Research Letters