Ceres Just Got A Lot More Interesting to Astrobiologists

Indigenous organics have been found on the largest body in the asteroid belt.

Ceres cryovolcano.jpeg
Ahuna Mons, shown in this simulated view as it might appear to someone standing on the surface of Ceres, is thought to be an ice volcano.

Maria de Sanctis from the Institute of Astrophysics and Planetology in Rome and her colleagues report in today’s issue of Science that they’ve found organic compounds on Ceres. What’s more, the organics originated on the dwarf planet itself, rather than arriving with an impacting comet or asteroid. The findings are based on their spectral analysis of about 1,000 square kilometers close to a crater called Ernutet on the object’s surface. NASA’s Dawn spacecraft is currently in orbit around Ceres, the largest body in the asteroid belt between Mars and Jupiter.

Water ice and organics were already known to be present there, but learning that they are indigenous—formed most likely by hydrothermal activity—is critical. When we consider that Ceres has clay minerals, carbonate rocks, and salts on or near its surface, the environment is similar to the one that prevailed on Earth some four billion years ago. In fact, organic compounds, plus energy, plus “building blocks” such as clay could make Ceres’ crust conducive to the origin of life. 

Ceres appears to be a rather unique case study of a hybrid between a terrestrial planet and an icy moon, which might have been warmer and friendlier to life a long time ago. How far might chemistry have evolved toward biology before it was frozen in place? The spectral similarity of the detected organics to ones found in carbonaceous chondrites suggest that we may find some intriguingly complex molecules if we send a probe to Ceres for a closer look.  

If the dwarf planet has a subsurface ocean as some have speculated, the existence of life today is not out of the question. In this scenario, hydrothermal energy would likely power volcanoes that push liquid water from deep below onto the surface of Ceres. If so, we might find molecules consistent with biology on the surface.

Since Ceres is closer than any other high-priority astrobiological target besides Mars, and is not exposed to huge radiation fluxes like Europa is, sending a lander there would be relatively quick and easy. Indeed, Ceres may very well become one of the new favorite targets for astrobiologists.