Evidence of life on Mars may be over 6 feet deep: NASA

Washington : Rovers exploring Mars, such as NASA’s Curiosity and Perseverance and others, may have to dig about 6.6 feet (two metres) or more under the surface of the Red Planet to find signs of ancient life, according to a new laboratory experiment by the US space agency.
It is because ionising radiation from space degrades small molecules such as amino acids relatively quickly, NASA said.
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 widely used by terrestrial life as a component to build proteins that are essential to life.
“Our results suggest that amino acids are destroyed by cosmic rays in the Martian surface rocks and regolith at much faster rates than previously thought,” said Alexander Pavlov of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, in a statement.
“Current Mars rover missions drill down to about two inches (around five centimetres). At those depths, it would take only 20 million years to destroy amino acids completely. The addition of perchlorates and water increases the rate of amino acid destruction even further,” he added.
Twenty million years could be a relatively brief amount of time because scientists are looking for evidence of ancient life on the surface which would have been present billions of years ago when Mars was more like Earth.