Both the atmospheric methane and the preserved carbon have inspired confidence that NASA's forthcoming Mars 2020 rover and the European Space Agency's ExoMars rover could uncover additional evidence for ancient life on the Red Planet.
Curiosity found the organic material in sedimentary rocks - mudstone - after drilling into four areas of the Gale crater, an ancient lake bed in which Curiosity originally landed in 2012.
And while methane had previously been found in Mars' atmosphere in "large, unpredictable plumes", NASA said it has now found methane levels that follow seasonal trend changes with more methane appearing in warm summer months before dropping in the winter. Researchers said they can't rule out a biological source.
"The detection of organic molecules and methane on Mars has far-ranging implications in light of potential past life on Mars", she said.
Utrecht University astrobiologist Inge Loes ten Kate said: "The question of whether life might have originated or existed on Mars is a lot more opportune now that we know that organic molecules were present on its surface at the time".
As some of those molecules are often fragments of kerogens - organic molecules known to be the residue of living matter - the paper's authors cautiously suggest the Martian finds could suggest biological processes once took place on Mars. It arrived at Mars in 2016 and is now mapping concentrations of methane and other gases from on high. The Wikipedia article on "organic matter" makes the point: "Organic molecules can also be made by chemical reactions that don't involve life".Читайте также: Donald Trump attorney says Kim Jong Un 'begged' for summit
"[Curiosity's] molecular observations do not clearly reveal the source of the organic matter in [Gale Crater]".
One thing is for sure, though - whatever we can figure out about the chemistry of Mars, it's nearly certainly going to add precious details to our understanding of life in the cosmos. "That doesn't mean life, but organic compounds are the building blocks of life", he added. The Martian surface is bombarded with radiation that can degrade organic compounds, explains Eigenbrode.
"This is the first time we've seen something repeatable in the methane story, so it offers us a handle in understanding it", said lead author of the second paper Chris Webster of NASA's Jet Propulsion Laboratory (JPL). "We don't know, but these results tell us we are on the right track". In this case, Curiosity found molecules with names like "thiophene" (C4H4S) and "dimethylsulfide" (C2H6S) that aren't all that rare in the solar system.
A seasonal change in methane levels is exciting, he said, because 95 percent of the methane observed on Earth is the result of biology. "And the last one is geological processes, meaning the rock-forming processes themselves". And NASA didn't launch another mission to Mars for over a decade.
Webster theorizes the methane created either now or long ago is seeping from deep underground reservoirs up through cracks and fissures in the crust. The host of the session, assistant director of science for communications in NASA's Planetary Science Division Michelle Thaller, began by clearing up any rumors that the agency would announce that they had found alien life.
I asked everyone I spoke with if they thought there was life on Mars, and the consensus was maybe, maybe not. Curiosity can only drill a few centimeters into Martian rocks, and it lacks the advanced tools necessary to search for more complex markers of life.При любом использовании материалов сайта и дочерних проектов, гиперссылка на обязательна.
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