The search for life on Mars will have to be done in the depths of the red planet, not on the surface, NASA researchers announce after an interesting study recently published in the journal Astrobiology.
As we well know, different missions of this American space agency such as Curiosity Rover and Mars 2020 Perseverance Rover currently maintain space exploration vehicles (Rover) on the surface of Mars, whose main objective is to determine if the planet ever had the environmental conditions suitable for supporting life.
To do this, both rovers look for signs of possible ancient microbial life, particularly by collecting special rock and soil samples that are recognized as having the potential to preserve remnants of life over time.
One of the signs that could prove that Mars was once habitable is finding organic matter, specifically amino acids, in rock samples.
NASA describes us that “amino acids can be created by life and by non-biological chemistry. However, finding certain amino acids on Mars would be considered a potential sign of ancient Martian life because they are essential for terrestrial life as a component for building proteins.”
Now, the new research described here tells us that in order to find any evidence of amino acid residues you have to dig much deeper, at least 2 meters underground. This is because the researchers found that these biomolecules are destroyed by cosmic rays in rocks on the Martian surface at a faster rate than previously thought.
Cosmic rays, which are high-energy particles generated by powerful events on the Sun and in deep space (such as solar flares and exploding stars), attack the surface of Mars in this way due to its lack of a magnetic field and its “ weak” atmosphere, conditions totally opposite to Earth but believed to have once been part of the red planet.
Scientists are looking for evidence of ancient life on the surface that would have been present billions of years ago when Mars was most like Earth, however current Mars Rover missions go only to about five centimeters.
At these depths, according to their estimates, it would take only 20 million years to completely destroy the amino acids, so it is possible that the potential remains of life have already been degraded on the Martian surface unprotected from cosmic rays.
To verify the rate of destruction of these biomolecules, the researchers mixed different types of amino acids in soil, air and temperature that simulated Martian conditions, they were also exposed to gamma radiation bombardment that represents the doses of cosmic rays received by the nearby subsoil Martian.
Thus, they determined that new search strategies other than shallow sampling should be implemented, since there could be a greater probability of finding a signal inside the planet, with less vulnerability to radiation, than on its surface.
Or, if this is not the case or you do not have the capacity to achieve this, Alexander Pavlov, author of the study, mentions for NASA that “surface drilling sampling missions have to look for recently exposed outcrops, for example, recent microcraters with ages less than 10 million years or the material expelled from said craters».
For more details you can consult: Astrobiology.
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