As the search for life on Mars intensifies with Perseverance, Curiosity, and China’s Zhurong rover looking for signs of ancient bacterial life, a new study indicates they will have to work harder and dig deeper. Lab experiments have revealed that the rovers will have to dig at least 6.6 feet to find any possible signs.
Scientists suspect that radiation from space could have degraded small molecules such as amino acids relatively quickly on the surface. Finding amino acids on mars can be considered a potential sign of ancient Martian life because amino acids can be created by life, and are widely used by life on Earth to build proteins.
“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. 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,” Alexander Pavlov, scientist with Nasa’s Goddard Space Flight Center in Greenbelt said in a statement.
The result suggests a new search strategy for missions that are limited to sampling at shallow depths.
Just like Earth’s thick atmosphere and global magnetic field that shields the surface from most cosmic rays, Mars also had these features but lost this protection as it aged. However, there’s evidence that billions of years ago, liquid water persisted on the surface of the Red Planet.
Organic matter has been found on Mars by Nasa’s Curiosity and Perseverance rovers. (File Pic)
Since liquid water is essential for life, scientists are searching for evidence of ancient Martian life by examining Mars rocks for organic molecules such as amino acids.
The team mixed several types of amino acids in silica, hydrated silica, or silica and perchlorate to simulate conditions in Martian soil and sealed the samples in test tubes under vacuum conditions to simulate the thin Martian air. Some samples were kept at room temperature, about the warmest it ever gets on the surface of Mars, while others were chilled to a more typical minus 67 degrees Fahrenheit.
The samples were blasted with various levels of gamma radiation similar to what Mars would have experienced over 80 million years of exposure. This experiment is the first to mix amino acids with simulated Martian soil.
While amino acids have not been found on Mars yet, they have been found in meteorites, including those from Mars.
Organic matter has been found on Mars by Nasa’s Curiosity and Perseverance rovers; however, it is not a conclusive sign of life since it could have been created by non-biological chemistry.
The results of the experiment imply that it is likely that the organic material observed by these rovers has been altered over time by radiation and therefore not as it was when formed.