It sure doesnt pay to underestimate Ceres: NASAs Dawn spacecraft has spotted signs of organic molecules on the frigid dwarf planet.

The findings, published this weekin the journal Science, may shed light on the prevalence of pre-life chemistry in the solar system while marking Ceres as one of the worlds that could potentially host microbial life.

Because Ceres is a dwarf planet that may still preserve internal heat from its formation period and may even contain a subsurface ocean, this opens the possibility that primitive life could have developed on Ceres itself, Michael Kppers of the European Space Agency, who was not involved in the study, wrote in a commentary. It joins Mars and several satellites of the giant planets in the list of locations in the solar system that may harbor life.

Ceres, one of five dwarf planets in the solar system, is also an asteroid the largest of them, in fact. Formed around 4.5 billion years ago, it sits in the belt of rocky debris that lies between the orbits of Mars and Jupiter.

Asteroids are the leftover building blocks of planetary formation, largely unchanged by thegeologic processes that occur onEarth and other planets. Bystudying these space fossils, scientists hope topiece together what the early solar system looked like.

Among the asteroids, Ceres is special. As a dwarf planet, it got stuck somewhere along the way to becoming a full-grown world. Frozen in this state, Ceres also offers a snapshot of planetary adolescence.

Scientists have long wondered whether asteroids had not just water but also organic matter that could have been brought to Earth, perhaps providingthe right chemical ingredients for lifeto emerge. Water and organic molecules have been discovered in meteorites that are thought to be chunks of asteroids that fell to Earth. But its also possible these meteorites werecontaminated or transformed by Earths environment.

Hints of organics have been found on two actual asteroids, 24 Themis and 65 Cybele, though in both casesthe signal was pretty weak. (ESAs Rosetta mission found clear signals on comet 67P/Churyumov-Gerasimenko howeverthat, of course, is not an asteroid.)

Thanks to theDawn spacecraft, which reached the frigid little world in 2015, scientists have detected super-bright salt deposits in Cerescraters and identified Ahuna Monsas an ice volcano. But now, using its Visible and Infrared Mapping Spectrometerinstrument, the spacecraft has spottedorganics lying on the surface.

When light hits any material, that material will absorb certain wavelengths while reflecting the rest. Since the absorbed wavelengths are unique to the materials properties, those missing bands of light serve asa chemical fingerprint that a spectrometer can useto determinethe composition of the surface.

The organic matter detected on Cereslies in a roughly 1,000-square-kilometer area near an approximately 50-kilometer-wide crater named Ernutet. While the scientists arent sure exactly what the compounds are, the fingerprint is characteristic of material containing carbon-hydrogen bonds, and may include components like methyl and methylene.

We were not expecting to see something like this on the surface of Ceres, said study coauthor Christopher Russell, a UCLA planetary scientist and Dawns principal investigator. These simple molecules, he added, are really pre-biological, but theyre in the family of materials that we would expect if Ceres was working its way along the complexity path.

Together with some of the other stuff already known to be on Ceres, this makes for what could theoretically be a life-friendly environment, perhaps even an environment with the right chemical precursors for life.

The combined presence on Ceres of ammonia-bearing hydrated minerals, water ice, carbonates, salts, and organic material indicates a very complex chemical environment, suggesting favorable environments to prebiotic chemistry, the study authors wrote.

But how did the organics get there?

One possibility is that they were delivered by comets or other asteroids. But the distribution of theorganic material doesnt match the pattern that would have beenleft by an impact. Besides, the authors pointed out,any organic-rich body that slammed into Ceres would probably be superheated by the collision, causing much of that organic matter to break down.

If the organics really didoriginate on Ceres itself, as the authors suspect, then researchers willhave to figure out how this material made it from the interior of thedwarf planet to its surface. For now, thatprocess remains a mystery.

Whatever the explanation, the findings show that Ceres like Mars and other worlds such asSaturns moonEnceladus may also have the right chemical ingredients for life.

Scientists could learn more if they were able tolook at the isotopic composition of thewater ice, Russell added. This could reveal whether Ceres formed where it lies, or whether it formed farther out and eventually moved in.

But that would require a lander of some sort, he pointed out, not the type ofremote sensing instruments on Dawn. That job, he added,would have to wait for a future mission to the dwarf planet.

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NASA's Dawn mission finds life's building blocks on dwarf planet Ceres - Los Angeles Times