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. The new paper suggests the dwarf planet may also have produced enough chemical energy – thanks to radioactive decay of material in its core – to make its internal ocean warm. Maybe warm enough that, in concert with the presence of water and carbon, microbes would have felt at home.
A February observation with the James Webb Space Telescope spotted moon S/2025 U1, a rock just 10km in diameter.
Matthew Tiscareno of the SETI Institute said the moon “is smaller and much fainter than the smallest of the previously known inner moons.”
Any microbes that lived on Ceres would have been “chemotrophs” – organisms that rely on chemical energy rather than solar energy, because even when the dwarf planet was warm inside, its surface was hellishly cold and exposed to radiation.
NASA thinks the paper’s findings have implications for students of other small icy bodies in the solar system, because if they too had radioactive cores they might have had their own periods of habitability.
Humanity has first-hand evidence that planets like our own, warmed by a star and internal heat, can host life. We’ve also seen moons tugged by gravitational forces produce environments that look capable of hosting some sort of life.
The paper suggests Ceres could have offered life another niche.
Evidence of any LGMs – little green microbes – will be devilishly hard to find, as the paper suggests that any “period of habitability” on Ceres existed between ~0.5 and 2 billion years after its formation. Astroboffins think the dwarf planet formed 4.5 billion years ago, so any residents perished at least 2.5 billion years ago. ®
Source: The register