Astronomy

As usual, I'm going to link to the journal article in Astrobiology. The conclusion reads:

We agree with Carl Sagan’s claim that extraordinary claims require extraordinary evidence (Sagan, 1979) and understand that any purported detection of life on Mars will necessarily be met with intense scrutiny. In addition, in practice with established norms in the field of astrobiology, we note that the certainty of a life detection beyond Earth will require multiple lines of evidence. Nevertheless, our approach has led us to estimate that the Cumberland mudstone conservatively contained 120–7700 ppm of long-chain alkanes and/or fatty acids before exposure to ionizing radiation. We argue that such high concentrations of long-chain alkanes are inconsistent with a few known abiotic sources of organic molecules on ancient Mars, namely delivery of organics by IDPs and meteorites, atmospheric fallout and deposition from photochemical haze, and organic production from serpentinization and Fischer–Tropsch reactions on the Red Planet. In contrast, it is not unreasonable to hypothesize that an ancient martian biosphere would be capable of producing this level of complex organic enrichment in martian mudstone deposits, and that allochthonous delivery of hydrothermally synthesized organics could have contributed to the abundance of alkanes found in the Cumberland mudstone. To improve the ability to predict the types and concentrations of organic molecules that could have been preserved in ancient sedimentary rocks exposed to ionizing radiation at the martian surface––regardless of their origin (biotic or abiotic)––we recommend experimental studies that determine the radiolytic degradation rates of kerogens, alkanes, and fatty acids in Cumberland-like Mars analogs under Mars-like conditions.