Dwarf planet Ceres, the unpleasant lump of icy rock orbiting between Mars and Jupiter, once had an environment in which microbes might have thrived. So says a paper titled "Core metamorphism controls the dynamic habitability of mid-sized ocean worlds-The case of Ceres" published this week in the journal Science Advances. As distilled by NASA, whose Dawn spacecraft captured the data used in the paper, previous examinations of Ceres suggested that ice present on its surface came from water that percolated up from internal reservoirs of liquid brine. Salt deposits on Ceres' surface suggest that brine contained carbon, which microbes need.