Mars Has Ancient Organic Material, Mysterious Methane

  • Mars Has Ancient Organic Material, Mysterious Methane

Mars Has Ancient Organic Material, Mysterious Methane

NASA's Curiosity Rover has explored the surface of Mars for five years, and has recently resumed drilling into rocks on the surface.

What they can't say yet is whether there is, or ever was, life on the Red Planet.

The new evidence comes from a pair of rocks.

NASA's Curiosity Mars Rover drilled this hole to collect sample material from a rock target called "Buckskin" on July 30, 2015, during the 1060th Martian day, or sol, of the rover's work on Mars.

But the SAM results were hard to interpret - there were a lot of extraneous signals that didn't make any sense.

"What we have detected is what we would expect from a sample from an ancient lake environment on Earth", said Eigenbrode, of NASA's Goddard Space Flight Center.

Potential contaminants were analyzed and accounted for, so the results are the most conclusive yet.

In four locations, including the spot nicknamed Mojave (pictured here), the Curiosity rover discovered thiophenes (molecules that include a ring of carbon and sulphur atoms) and other substances that on Earth can be linked to biological activity.

Dr Webster said the data pointed to methane trapped in water-based crystals deep under the planet's surface, which slowly seep to the surface when temperatures rise. The 96-mile crater, named for Australian astronomer Walter F. Gale, was most likely formed by meteor impact between 3.5 to 3.8 billion years ago. But it is the preservation of the material that is important - if there is this much organic matter preserved close to the surface, then there should be even better protected material at greater depths. "If you can do this on Mars, imagine what you can do with analytical facilities available to us on Earth", he says. It can also arise from lifeless interactions between flowing water and hot rocks whereas other simple organic molecules are known to exist in some meteorites and interstellar gas clouds.

She isn't ruling out that possibility, however.

"If there are no organics, we can pretty much forget about there being life or ever having been life on Mars", says Dr. Weintraub.

Previously, it was an open question whether signs of life might be preserved on the now-harsh Martian surface. Organic molecules pop up frequently in space, but it's neat that Mars had life's building blocks during a time when many think it was more habitable. The Martian surface is bombarded with radiation that can degrade organic compounds, explains Eigenbrode. The scientists took questions from the public as they revealed increasingly more information about Curiosity's latest developments.

A French-built instrument revealed "several organic molecules and volatiles reminiscent of organic-rich sedimentary rock found on Earth, including: thiophene, 2- and 3-methylthiophenes, methanethiol, and dimethylsulfide", said the Science report. So like the organic molecules, it's not an unambiguous biosignature.

"This is the first time we've seen something repeatable in the methane story, so it offers us a handle in understanding it", Chris Webster of NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, said.

Webster theorizes the methane created either now or long ago is seeping from deep underground reservoirs up through cracks and fissures in the crust. Tellingly, the methane levels appear to periodically spike in time with Martian seasons, being about three times higher in the sunny summertime than in the darker, colder winter.