2023-08-11 04:00:11
Patterns indicative of a cyclical climate, similar to that of the Earth, have just been discovered on Mars by scientists from the CNRS, the University Toulouse III – Paul Sabatier and the University Claude Bernard Lyon 1, thanks to the NASA’s Curiosity rover, with the participation of CNES. This major discovery opens the way to new perspectives for research on the origin of life (This article is devoted to the origins of life from a scientific point of view. The aspects…). The results of this study are published on August 9, 2023 in the journal Nature.
Hexagonal patterns active in the Racetrack Playa Basin in California, analogous to fossilized ones seen on Mars. The mud forms a hexagon pattern due to seasonal variations in humidity. This pattern is preserved because the cold in winter and the predominant aridity in summer prevent the vegetation (Vegetation is the set of wild or cultivated plants (flora) which…) from settling there.
© Cody Duncan
Unlike the surface of the Earth, that of the planet Mars is not renewed by plate tectonics (Plate tectonics (first called continental drift) is the current model of…). It has thus preserved vast spectacular lands through the abundance of fossil rivers and lakes dating back several billion years. Since 2012, NASA’s Curiosity rover, the first to explore such remains, had already detected the presence of simple organic molecules that could be formed by geological or biological processes.
But the emergence of primitive life forms, as imagined by scientists, first requires favorable environmental conditions for the spontaneous arrangement of these elements into complex organic compounds. This is precisely what a research team from the Institute (An institute is a permanent organization created for a certain purpose. It is…) for research in astrophysics (Astrophysics (from the Greek astro = star and physiqui = physics) is a branch…) and planetology (Planetology is the science of studying the planets. The discipline covers many…) (CNRS/University of Toulouse III – Paul Sabatier/CNES) and Geology laboratory (Geology, from the ancient Greek γη- (gê-, “earth”) and…) of Lyon: Earth, planets, environment (The environment is everything that surrounds us. It is the whole natural elements and…) (CNRS/ENS de Lyon/Claude Bernard University (Claude Bernard, born July 12, 1813 in Saint-Julien (Rhône) and died on…) Lyon 1) and their American and Canadian colleagues just highlighted.
Hexagonal fossil pattern in sedimentary rocks analyzed by Curiosity on the 3154th day of its advance through Gale Crater on Mars.
© NASA/JPL-Caltech/MSSS/IRAP/Rapin et al./Nature
They discovered deposits of salts forming a hexagonal pattern in sedimentary layers dated 3.8 to 3.6 billion years ago, thanks to the American Mastcam instrument and the Franco-American ChemCam instrument from Curiosity. Similar to the hexagons observed in seasonally drying terrestrial basins, they constitute the first fossil evidence of a cyclic, regular and long-lasting Martian climate, organized into dry and wet seasons. By allowing molecules to interact at different concentrations and repeatedly, independent experiments in the laboratory have shown that this environment offers the ideal conditions for forming complex compounds that are precursors and constituents of living organisms such as RNA.
These new observations allow scientists to take a new look at the large-scale images obtained from orbit, which have already located many terrains at similar composition. They now know where to look for traces of the natural processes at the origin of life, of which there is no trace left on Earth.
References
Sustained wet-dry cycling on early Mars
Rapin W, Dromart G, Clark BC, Schieber J, Kite ES, Kah LC, Thompson LM, Gasnault O, Lasue J, PY. Meslin, PJ Gasda, NL Spear.
Nature, August 9, 2023.
DOI:
1691792348
#traces #processes #origin #life