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This view of the Viking 2 shows Utopia Planitia on Mars in 1976. Some researchers believe that the main instrument of the Viking lander may have burned organic molecules in samples of collected soil. Credit: NASA / JPL-Caltech
More than 40 years ago, a NASA mission accidentally destroyed what would have been the first discovery of organic molecules on Mars, according to a report by New Scientist
. his Curiosity rover discovered organic molecules – which make up life as we know it – on Mars. This follows the first confirmation of organic molecules on Mars in 2014. But because small, carbon-rich meteorites often weigh on the red planet, scientists have suspected for decades the existence of organic matter on Mars. But the researchers were stunned in 1976, when NASA sent two Viking landers to Mars to search for organic compounds for the first time and found none.
Scientists did not know what to make Viking conclusions – how could there be any organic? on Mars? "It was totally unexpected and inconsistent with what we knew," said Chris McKay, a global scientist at NASA's Ames Research Center in New Scientist. [Viking 1: The Historic First Mars Landing in Pictures]
A possible explanation emerged when NASA's Phoenix lander discovered perchlorate on Mars in 2008. This is a salt used to make fireworks on Earth; it becomes very explosive under high temperatures. And while the surface of Mars is not too hot, the main instrument aboard the Viking landers, the gas chromatograph-mass spectrometer (GCMS), had to heat the Martian soil samples for find organic molecules. And because the perchlorate is in the soil, the instrument would have burned all the organic compounds in the samples during this process.
The discovery of perchlorate has rekindled scientists' belief that Viking landers could have found organic matter on Mars. McKay said, "You get a new idea, and you realize that everything you thought was wrong."
However, finding perchlorate did not provide concrete evidence that Viking landers found and accidentally destroyed organic molecules.
The variety of organic molecules that Curiosity recently discovered on the red planet included chlorobenzene. This molecule is created when carbon molecules burn with perchlorate, so scientists suspect that it could have been created when soil samples were burned, according to New Scientist.
The researchers were inspired by this indirect evidence to dig a little deeper. evidence that viking landers could have found and then destroyed organic matter. In a new study, published in June in the Journal of Geophysical Research: Planets, Melissa Guzman of the LATMOS Research Center in France, McKay and a handful of collaborators revisited the Viking lander's data to see if anything was missing .
found that Viking landing gear also detected chlorobenzene, which the researchers claimed to have formed from burning organic material in soil samples.
However, this is not a proof that Viking landers found organic molecules and accidentally burned them. New scientist Even the scientists who completed this survey are divided.
Guzman said that she is still not completely convinced that the chlorobenzene that they detected was formed when organic matter in Martian soil was burned. She said the molecule could have come from the Earth aboard NASA's equipment.
But despite this skepticism, others are convinced; "This document really seals the case," said Daniel Glavin, an astrobiologist at NASA's Goddard Space Flight Center, who was not involved in the study, said New Scientist.
Original article on Space.com
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