Nasa Rover curiosity found the greatest organic compounds never seen on Mars, raising attractive questions about the question of whether life emerged on the Red Planet billions of years ago.
The compounds were detected in a rock sample of 3.7 billion people taken from Yellowknife bay, an old bed of Martian lake that hosted all the ingredients necessary for life in the warmer and wetter past on the planet.
The tests aboard the rover revealed that the rock contained long -chain alcanes, organic molecules considered as leftover fatty acids. The compounds can be made by lifeless chemical reactions, but are crucial constituents of cell membranes in all living organisms of the earth.
Researchers do not claim to have found a biosignature – a “firearm” indicating that life was once present – but an expert declared that the material represented the best chance that scientists have ever had to identify the remains of life on March.
“These molecules can be manufactured by chemistry or biology,” said Dr. Caroline Freissinet, an analytical chemist who led research in atmospheres and Space Observations laboratory in Guyancourt, near Paris. “If we have long chain fatty acids on Mars, they could come – and this is only a hypothesis – from the degradation of the membrane of the cells present 3.7 billion years ago.”
Curiosity Rover has dropped more than 20 miles (32 km) through the scabies crater since its landing on March in 2012. Six years in the mission, it detected traces of organic products In the old Mudstone, but all were relatively short carbon chain molecules.
For the latest study, Freissinet and his colleagues have developed a new procedure to further test the sample drilled from the Mudstone. This time, curiosity has detected much larger organic products, namely Decane, Undecane and Dodecan.
Work on Earth has shown that the Martian rock sample, known as Cumberland, probably contained carboxylic acids, or fatty acids, which converted into alkaks in the heating process. “Although abiotic processes can train these acids, they are considered as universal products of biochemistry, terrestrial and perhaps Martians,” wrote scientists Proceedings of the National Academy of Sciences.
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A more in -depth analysis of organic materials has only aggravated the plot. When organisms on Earth make fatty acids, compounds tend to contain more numbers than odd numbers of carbon atoms. Indeed, some enzymes build fatty acids by adding two carbon atoms at a time. Scientists have also seen clues in Martian organics. “Cumberland teases us,” said Freissinet. “The one in the middle with 12 carbon is more abundant than the other two. We have the same trend on Mars, but a trend drawn from three molecules is not a real trend. However, it is very intriguing.”
The discovery suggests, at the very least, that the organic signatures of life can be kept in Martian rock for billions of years, strengthening the hopes that life has never emerged on the planet, its remains could still be found.
The urgent question is what to do next. Curiosity transports a second rock sample that scientists want to analyze for even larger organic matter. This could stimulate proofs of more fatty acids containing a uniform number of carbon. But it would still not be successful.
John Eler, professor of geology and geochemistry at the California Institute of Technology, said that the analysis of the various isotopes of carbon and hydrogen in organics could reveal their origins. However, tests require equipment found in only a handful of laboratories on earth. “Currently, there is no plausible path to make such measures using an in situ instrument on Mars,” he said. This will have to wait for a mission to return from the Mars sample.
“The results reported in this article present the best chances that we have seen to identify the remains of life on Mars,” said Eiler. “But sealing the agreement absolutely requires the return of such samples to earth.”