NASA’s Curiosity rover has found “tough” organic molecules preserved in three-billion-year-old sedimentary rocks near the Martian surface and it suggests the planet could have supported ancient life.
Curiosity’s lab analysis also found seasonal variations in the levels of methane in the atmosphere of the planet.
MOLECULE – Curiosity has discovered ancient organic molecules in Gale Crater using its SAM instrument. Credit: NASA’s Goddard Space Flight Center
Organic molecules contain carbon and hydrogen, and also may include oxygen, nitrogen and other elements. While commonly associated with life, organic molecules also can be created by non-biological processes and are not necessarily indicators of life.
“With these new findings, Mars is telling us to stay the course and keep searching for evidence of life,” said Thomas Zurbuchen, associate administrator for the Science Mission Directorate at NASA Headquarters, in Washington.
“I’m confident that our ongoing and planned missions will unlock even more breathtaking discoveries on the Red Planet.”
“Curiosity has not determined the source of the organic molecules,” said Jen Eigenbrode of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, who is lead author of one of the two new Science papers. “Whether it holds a record of ancient life, was food for life, or has existed in the absence of life, organic matter in Martian materials holds chemical clues to planetary conditions and processes.”
Although the surface of Mars is inhospitable today, there is clear evidence that in the distant past, the Martian climate allowed liquid water – an essential ingredient for life as we know it – to pool at the surface. Data from Curiosity reveal that billions of years ago, a water lake inside Gale Crater held all the ingredients necessary for life, including chemical building blocks and energy sources.
As to methane found in the Martian atmosphere, (it was found earlier, too), Chris Webster of NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California, lead author of the second paper, said:
GALE CRATER A panorama of Gale Crater, taken by the Curiosity rover on Mars.
GALE CRATER – A panorama of Gale Crater, taken by the Curiosity rover on Mars. Image credit: NASA
“This is the first time we’ve seen something repeatable in the methane story, so it offers us a handle in understanding it.”
“This is all possible because of Curiosity’s longevity. The long duration has allowed us to see the patterns in this seasonal ‘breathing.’”
The rock samples were analyzed by SAM, which uses an oven to heat the samples (in excess of 900 degrees Fahrenheit, or 500 degrees Celsius) to release organic molecules from the powdered rock.
Finding methane in the atmosphere and ancient carbon preserved on the surface gives scientists confidence that NASA’s Mars 2020 rover and ESA’s (European Space Agency’s) ExoMars rover will find even more organics, both on the surface and in the shallow subsurface.
These results also inform scientists’ decisions as they work to find answers to questions concerning the possibility of life on Mars.
“Are there signs of life on Mars?” said Michael Meyer, lead scientist for NASA’s Mars Exploration Program, at NASA Headquarters. “We don’t know, but these results tell us we are on the right track.”
The results are published in the June 8 edition of the journal Science.