NASA’s Curiosity Mars rover has detected the largest organic (carbon-containing) molecules ever found on the red planet. The invention is probably the most significant findings within the seek for evidence of past life on Mars. It is because, on Earth at the least, relatively complex, long-chain carbon molecules are involved in biology. These molecules could actually be fragments of fatty acids, that are present in, for instance, the membranes surrounding biological cells.
Scientists think that if life ever emerged on Mars it was probably microbial in nature. Because microbes are so small, it’s difficult to be definitive about any potential evidence for all times found on Mars. Such evidence needs more powerful scientific instruments which might be too large to be placed on a rover.
The organic molecules found by Curiosity consist of carbon atoms linked in long chains, with other elements bonded to them, like hydrogen and oxygen. They arrive from a 3.7-billion-year-old rock dubbed Cumberland, encountered by the rover at a presumed dried-up lakebed in Mars’s Gale Crater. Scientists used the Sample Evaluation at Mars (Sam) instrument on the NASA rover to make their discovery.
Scientists were actually searching for evidence of amino acids, that are the constructing blocks of proteins and due to this fact key components of life as we understand it. But this unexpected finding is sort of as exciting. The research is published in Proceedings of the National Academies of Science.
Among the many molecules were decane, which has 10 carbon atoms and 22 hydrogen atoms, and dodecane, with 12 carbons and 26 hydrogen atoms. These are referred to as alkanes, which fall under the umbrella of the chemical compounds referred to as hydrocarbons.
It’s an exciting time within the search for all times on Mars. In March this 12 months, scientists presented evidence of features in a special rock sampled elsewhere on Mars by the Perseverance rover. These features, dubbed “leopard spots” and “poppy seeds,” might have been produced by the motion of microbial life within the distant past, or not. The findings were presented at a US conference and haven’t yet been published in a peer reviewed journal.
The Mars Sample Return mission, a collaboration between NASA and the European Space Agency, offers hope that samples of rock collected and stored by Perseverance may very well be delivered to Earth for study in laboratories. The powerful instruments available in terrestrial labs could finally confirm whether or not there is obvious evidence for past life on Mars. Nevertheless, in 2023, an independent review board criticized increases in Mars Sample Return’s budget. This prompted the agencies to rethink how the mission may very well be carried out. They’re currently studying two revised options.
Signs of Life?
Cumberland was present in a region of Gale Crater called Yellowknife Bay. This area comprises rock formations that look suspiciously like those formed when sediment builds up at the underside of a lake. One among Curiosity’s scientific goals is to look at the prospect that past conditions on Mars would have been suitable for the event of life, so an ancient lakebed is the proper place to search for them.
The researchers think that the alkane molecules may once have been components of more complex fatty acid molecules. On Earth, fatty acids are components of fats and oils. They’re produced through biological activity in processes that help form cell membranes, for instance. The suggested presence of fatty acids on this rock sample has been around for several years, but the brand new paper details the total evidence.
Fatty acids are long, linear hydrocarbon molecules with a carboxyl group (COOH) at one end and a methyl group (CH3) at the opposite, forming a sequence of carbon and hydrogen atoms.
A fat molecule consists of two most important components: glycerol and fatty acids. Glycerol is an alcohol molecule with three carbon atoms, five hydrogens, and three hydroxyl (chemically bonded oxygen and hydrogen, OH) groups. Fatty acids can have 4 to 36 carbon atoms; nevertheless, most of them have 12-18. The longest carbon chains present in Cumberland are 12 atoms long.
Mars Sample Return will deliver Mars rocks to Earth for study. This artist’s impression shows the ascent vehicle leaving Mars with rock samples. NASA/JPL-Caltech
Organic molecules preserved in ancient Martian rocks provide a critical record of the past habitability of Mars and may very well be chemical biosignatures (signs that life was once there).
The sample from Cumberland has been analyzed by the Sam instrument again and again, using different experimental techniques, and has shown evidence of clay minerals, in addition to the first (smaller and simpler) organic molecules found on Mars, back in 2015. These included several classes of chlorinated and sulphur-containing organic compounds in Gale crater sedimentary rocks, with chemical structures of as much as six carbon atoms. The brand new discovery doubles the variety of carbon atoms present in a single molecule on Mars.
The alkane molecules are significant within the seek for biosignatures on Mars, but how they really formed stays unclear. They may even be derived through geological or other chemical mechanisms that don’t involve fatty acids or life. These are referred to as abiotic sources. Nevertheless, the incontrovertible fact that they exist intact today in samples which have been exposed to a harsh environment for a lot of tens of millions of years gives astrobiologists (scientists who study the potential of life beyond Earth) hope that evidence of ancient life might still be detectable today.
It is feasible the sample comprises even longer chain organic molecules. It can also contain more complex molecules which might be indicative of life, quite than geological processes. Unfortunately, Sam isn’t able to detecting those, so the subsequent step is to deliver Martian rock and soil to more capable laboratories on the Earth. Mars Sample Return would do that with the samples already gathered by the Perseverance Mars rover. All that’s needed now could be the budget.
