The US Space Agency (NASA) did not find any traces of ancient or modern microbial life on Mars, but made two discoveries that bring this possibility closer in the future - but without even crossing the threshold of certainty.
Compelling evidence that confirms for the first time beyond doubt the presence of organic substances in Martian soil has brought to light the American Curiosity rover. In addition to organic matter, it has also been confirmed that not only a basic organic chemical compound, methane, exists in the Martian atmosphere, probably originating from an unknown source on the surface or underground of the planet, but also exhibits intense seasonal variations.
The two interlinked discoveries, presented in two separate publications in the journal Science, are particularly important in the field of astrobiology, namely the possibility of discovering life beyond the Earth, so NASA considered it appropriate to raise them by organizing a press conference. The combined presence of organic substances in the soil and methane in the atmosphere increases the chances for the existence of ancient microorganisms in Mars.
As ANT1 transmits, the collection of specimens that made the rover drill made from sludge in the Gael crater and their analysis by the Sami Analysis (SAM) at Curiosity, revealed a series of different organic molecules, ie carbon-based.
By 2015 there had been the first Curiosity indications for limited amounts of organic substances in Mars, but some doubts remained. This time, new samples from two points in the same crater, believed to be about three billion years old, have revealed evidence of the presence of several organic substances, some of which are volatile.
Some such substances, which have also been found on Earth, are thiophene, methylthiophene, methanethiol and dimethylsulfide. Researchers estimate that these molecules are parts of other larger organic molecules in Mars. However, they pointed out that at present they can not know whether the origin of this organic matter is biological, geological or meteoric, but they do not exclude the first case.
As for methane in the Martian atmosphere, the measurements show significant seasonal fluctuations in concentrations. In the past, small quantities of methane have been detected in the neighboring planet, and its origin has been a source of intense controversy. On Earth most of the methane is of biological origin (from microorganisms), but for ariane methane other abiotic explanations, such as its space origin, have been suggested.
The new data comes from atmospheric measurements over three Marian years (55 Earth months) that made Curiosity. It is revealed for the first time that methane levels on the "red planet" show a strongly seasonal cycle, ranging from 0.24 to 0.65 parts per billion (ppb). The highest concentration is recorded every year towards the end of summer in the northern hemisphere of Mars.
Scientists are now excluding various possible sources of methane origin. They consider it possible that large quantities of this gas are trapped and stored in the Martian subsoil in water-based crystals called encapsulation compounds or scabs. According to this theory, seasonal changes in global warming are likely to cause fluctuations in the release of methane in the Martian atmosphere. In any case, further efforts will be made to understand the methane cycle in Mars.
Certain detection of organic molecules and methane in Mars increases the likelihood of the neighboring planet once living a life. The Curiosity had shown since 2014 that the Gael crater had conditions suitable for life about 3.5 billion years ago, coincidentally at a time when life on Earth had begun to develop in the form of microorganisms.
Therefore, although there is still no evidence, it is not unlikely that there would be any form of life in Mars, since it is now established, after the new findings, that organic substances existed on its territory at that distant epoch.
Life on Earth uses and produces four basic types of organic substances: carbohydrates, lipids, proteins and nucleic acids. Each of these consists of smaller organic molecules, such as sugars, amino acids and nucleotides. Making the assumption that (hypothetical) Martian life would not differ greatly from Earth, scientists now focus their attention on finding these fundamental stones of life in Mars.
NASA has made it known that Curiosity, which had stopped drilling and collecting samples in October 2016 because of a mechanical problem, has just begun its work. The harsh scientific rover, which reached Mars in August 2012, continues slowly but steadily on Mount Sarp, a mountain about 5,000 meters high at the center of the Gael crater.
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