NASA’s Curiosity Mars Rover detected The largest organic (carbon-containing) molecule ever discovered on the Red Planet. This discovery is one of the most important findings to search for evidence of Mars’ past life. This is because relatively complex long-chain carbon molecules are involved in biology, at least on Earth. These molecules can actually be fragments of fatty acids, for example, in the membranes surrounding biological cells.
Scientists believe that if life appeared on Mars, it was probably a microorganism in nature. Because microorganisms are so small it is difficult to determine the potential evidence of life found on Mars. Such evidence requires more powerful scientific instruments that are too big to place on a rover.
Curious rover near the Mont Mercow site on Mars. Source: NASA/JPL-Caltech/MSSS
Organic molecules discovered by curiosity are made up of carbon atoms associated with long chains, with other elements attached to them, such as hydrogen and oxygen. They come from a 3.7 billion-year-old rock called Cumberland and run around the dried-up lakebed of Gale Crater on Mars. Scientists used it Sample analysis on MARS (SAM) instruments Make their discoveries with NASA’s rover.
Scientists were actually looking for evidence of amino acids. Amino acids are components of proteins and, therefore, as we know, are important components of life. However, this unexpected discovery is almost as exciting. This study is published in Proceedings of the National Academy of Science.
Among the molecules were decanes with dodecanes with 10 carbon atoms and 22 hydrogen atoms, with 12 carbons and 26 hydrogen atoms. These are known as alkanes and are under the umbrella of compounds known as hydrocarbons.
Looking for life on Mars is an exciting time. In March of this year, scientists Evidence presented of another rock feature sampled elsewhere on Mars by a patient rover. These characteristics, known as “leopard spots” and “poppy seeds,” may have been produced by the action of microorganisms in the distant past. The findings were published at the US Congress and have not yet been published in peer-reviewed journals.
Mars sample return The mission, a collaboration between NASA and the European Space Agency, hopes that samples of rocks collected and preserved by patience can be brought to Earth for research at the lab. The powerful instruments available in the ground lab will ultimately confirm whether there is clear evidence of Mars’ past life. However, in 2023 Independent Review Committee It criticized the increase in the budget for Mars sample returns. This has led the agency to rethink how it could carry out its mission. They are currently studying Two revision options.
Signs of life?
Cumberland was discovered in the area of ​​Gale Crater Yellowknife Bay. This area contains rock formations that look suspicious like them It forms during deposits They accumulate at the bottom of the lake. One of Curiosity’s scientific goals is to examine the outlook that past conditions on Mars were suitable for the development of life. Therefore, the ancient lake bottom is a great place to search for them.
The Martian rocks known as Cumberland were sampled in this study. Credit: NASA/JPL-Caltech/MSSS
Researchers believe that alkane molecules may have once been components of more complex fatty acid molecules. On the planet, fatty acids are fat and oil components. For example, it is produced through biological activity in a process that helps to form cell membranes. Proposed existence The fatty acids in this rock sample have been around for several years, but a new paper details the complete evidence.
Fatty acids are long linear hydrocarbon molecules with a carboxyl group (COOH) at one end and a methyl group (CH3) at the other end, forming chains of carbon and hydrogen atoms.
Fatty molecules are made up of two main components: glycerol and fatty acids. Glycerol is an alcohol molecule with three carbon atoms, five hydrogens, and three hydroxyls (chemically bound oxygen and hydrogen, OH) groups. Fatty acids have 4 to 36 carbon atoms. However, most of them are 12-18. The longest carbon chain found in Cumberland is 12 atoms.
Mars sample return delivers Mars rocks to Earth for research. This artist’s impression shows that the rising vehicle leaves Mars in rock samples. NASA/JPL-Caltech
Organic molecules conserved in the rocks of ancient Mars provide a significant record of Mars’ past habitat and may be chemical biosignatures (signs that life once existed).
Cumberland sample It has been analyzed SAM instruments have been used to provide evidence of clay minerals and many times using various experimental techniques. First (small, simpler) organic molecule It was found on Mars in 2015. These included several classes of chlorinated and sulfur-containing organic compounds in Gael Crater sedimentary rocks with chemical structures of up to six carbon atoms. The new discovery doubles the number of carbon atoms found in a single molecule on Mars.
Alkane molecules are important in searching for Mars biosignatures, but how they actually formed remains unknown. It can also be derived through geological or other chemical mechanisms that do not involve fatty acids or life. These are known as non-biological sources. However, the fact that samples that have been exposed to harsh environments for millions of years now exist in unharmed states gives astrobiologists (scientists studying the possibilities of living beyond the earth).
The sample may contain even longer chain organic molecules. It may also contain more complex molecules that represent life rather than geological processes. Unfortunately, Sam can’t detect them, so the next step is to bring Mars rocks and soil to more capable laboratories on Earth. Mars sample returns do this with samples already collected by the patient Mars rover. All you need now is a budget.
Derek Ward Thompson, professor of astrophysics at the University of Central Lancashire, and Megan Argo, senior lecturer at Astronomy at the University of Central Lancashire. This article will be republished from the conversation under a Creative Commons license. Please read Original article.
