The discovery that there was once life on the Red Planet – most likely during a time in the distant past when Mars was covered in rivers and oceans – would be one of the most important scientific discoveries in the history of human civilization.
So far we have yet to make such a find, however scientists may be closing in on it; according to a new NASA laboratory experiment, the Mars rovers may have been looking in the wrong place.
It turns out that the ionizing radiation from space degrades small molecules such as amino acids – some of which being important indicators of life – much more quickly than expected.
This means that the best signs of ancient alien life on Mars will most likely be found around two meters beneath the surface where such evidence will have remained relatively protected.
Either that, or rovers will need to target outcrops that have only recently been exposed.
“Current Mars rover missions drill down to about two inches (around five centimeters),” said Alexander Pavlov of NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
“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.”
“Missions with shallow drill sampling have to seek recently exposed outcrops – e.g., recent microcraters with ages less than 10 million years or the material ejected from such craters.”