Scientists have used data collected by NASA (NASA) the Curiosity Mars rover to measure for the first time the amount of total organic carbon - a key ingredient in the molecules of life - in Martian rocks.
Total organic carbon is one of several measurements that help us understand how much of a material is available as a feedstock for prebiochemistry and potentially biology. According to Jennifer C. Stern of NASA's Goddard Space Flight Center and others, the paper "Lake Phase of Mars 3.5 Billion Years Ago" was published on the website of " Proceedings of the National Academy of Sciences " on June 27. "Concentrations of organic carbon in mudstone", scientists "found at least 200 to 273 parts per million of organic carbon. This is consistent with the concentration of organic carbon in places on Earth where life is extremely low, such as parts of the Atacama Desert in South America." The amount of organic carbon found in the rock is comparable or even greater than that found in the Martian meteorite ."
Organic carbon is carbon bonded to hydrogen atoms. It is the basis of the organic molecules created and used by all known life forms. However, organic carbon on Mars is not proof of life there, as it can also come from non-living sources, such as meteorites and volcanoes, or form through surface reactions.
Organic carbon has been found on Mars before, but previous measurements only yielded information about specific compounds or measured only a portion of the carbon in the rock. The new measurements give the total amount of organic carbon in these rocks.
Although the surface of Mars is not suitable for life now, there is evidence that billions of years ago Mars had a climate more like Earth, with a thicker atmosphere and liquid water flowing into rivers and oceans. Since liquid water is necessary for life as we understand it, scientists believe that if Martian life ever evolved, it might have been sustained by key ingredients like organic carbon, if only they were present in sufficient quantities.
Curiosity advances the field of astrobiology by investigating the habitability of Mars and studying its climate and geology. The Curiosity rover drilled into samples of 3.5-billion-year-old mudstone rock in the Yellowknife Bay Formation of Gale Crater, the site of an ancient lake on Mars.
The mudstones of Gale Crater were formed from very fine sediments (from the physical and chemical weathering of volcanic rocks) that were deposited in the water at the bottom of the lake and were buried. Organic carbon is part of this material and is incorporated into the mudstone. In addition to liquid water and organic carbon, Gale Crater has other conditions favorable to life, such as chemical energy, low acidity, and other elements necessary for living things, such as oxygen, nitrogen, and sulfur.
"Basically, it would provide a habitable environment for life if it existed here," Stern said.
NASA's Curiosity Mars rover emerged from the shallow Yellowknife Bay depression At one point, telephoto images were captured using its right mast camera to create this panoramic view of geological diversity. (NASA)
