NASA experiment points to where life on Mars could be found

A study on the experiment titled "Rapid Radiolytic Degradation of Amino Acids in the Martian Shallow Subsurface: Implications for the Search for Extinct Life" has been published in the journal Astrobiology.

A recent NASA laboratory experiment indicates that potential signs of ancient life on Mars are more likely found about 6.6 feet (~2 meters) below the Martian surface. Researchers determined that ionizing radiation from space could quickly destroy small molecules like amino acids, erasing signs of life from the surface. Though amino acids can be created by non-biological chemistry or by life, their discovery on Mars would be strong evidence for terrestrial 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. Current Mars rover missions drill down to about two inches (around five centimeters). 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," said Alexander Pavlov of NASA's Goddard Space Flight Center in Greenbelt, Maryland.

Ionizing radiation comes from the Sun and other stars in the form of cosmic rays comprising high-energy particles, usually protons or helium ions, generated by events like solar flares or novae. These rays can destroy organic molecules yards (meters) deep into even rocks on Mars, unlike on Earth, where the thick atmosphere and magnetic field surrounding the planet protect the surface from the majority of cosmic rays.

"Our work is the first comprehensive study where the destruction (radiolysis) of a broad range of amino acids was studied under a variety of Mars-relevant factors (temperature, water content, perchlorate abundance) and the rates of radiolysis were compared," continued Pavlov.

You can read more from the study here.