NASA uncovers largest organic molecules on Mars to date

As reported by NASA, studies published in the journal "Proceedings of the National Academy of Sciences" (PNAS) highlight the potential for more advanced organic molecules on Mars than previously thought. Scientists describe the discovery of carbon chains with up to 12 atoms, detected on Mars in an area likely to have once been an ancient lakebed. This discovery, made by an investigative instrument aboard the Curiosity rover, could provide significant insights into the history of life on the Red Planet. The findings have been confirmed by an international team of scientists in a laboratory on Earth.

In a rock sample named "Cumberland," molecules such as decane, undecane, and dodecane were found. These compounds, consisting of 10, 11, and 12 carbon atoms, may be fragments of fatty acids, which are key building blocks of life on Earth. This discovery is particularly significant because only simple organic molecules had been found on Mars previously.

The discovery of larger organic molecules on Mars increases the chances of finding biosignatures that could indicate the presence of life. As NASA points out, such compounds may survive on Mars despite intense radiation and oxidation, which is promising for future missions aiming to bring samples back to Earth.

Research conducted by Caroline Freissinet from the French National Centre for Scientific Research (CNRS), described in the article, suggests that although these compounds may have formed through non-living processes, their presence proves the rover’s capability to identify long organic molecules on the Martian surface. "The provenance and distribution of these molecules are of high interest in the search for potential biosignatures on Mars,” researchers note in their report.

Scientists used an experimental procedure with a chemical enhancer to analyse mineral samples taken from a sedimentary deposit called Cumberland. In experimental conditions, samples were heated to about 850°C, allowing for gas chromatography and mass spectrometry. Among the results were the longest carbon chains observed on Mars to date, such as decane (C10H22), undecane (C11H24), and dodecane (C12H26).

Laboratory analyses showed that Martian mineral conditions might generate these carbon chains from other organic compounds, including benzoic acid, which was also present in the samples. "Although abiotic processes can form these acids, they are considered universal products of biochemistry, terrestrial, and perhaps Martian," researchers believe.

The "Cumberland" sample was collected in 2013 from Gale Crater. Curiosity, traversing the sediments of Gale Crater, which once might have been a lakebed, encountered various organic compounds, including chlorinated and sulphur-containing ones, suggesting the possibility of discovering more complex life markers in ancient rocks. Daniel Glavin from NASA emphasises that the presence of water in the crater for millions of years could have facilitated the chemistry necessary for life to originate.

Current technology only allows for superficial chemical composition studies of Mars. To determine whether any forms of life are preserved or still exist beneath the surface, future missions will be necessary. However, scientists believe that even now, we can rejoice in the possibility that these long carbon chains were once part of a form of life that evolved on another planet.

NASA scientists plan further research to better understand potential signs of life on Mars. "We are ready to take the next big step and bring Mars samples home to our labs to settle the debate about life on Mars," says Glavin. These studies are funded by the Mars Exploration Programme, and the Curiosity mission is conducted by the Jet Propulsion Laboratory in California.