NasaCuriosity Rover has found some of the best evidence to date that ancient life may have existed March – And an answer for what could have wiping it.
During drilling in rocks on Mount Sharp, the central peak of the Gale Crater of the Red Planet, the rover found signs of siderite, an iron carbonate whose presence suggests that Mars once had a carbon cycle. This suggests that Mars once had potentially habitable conditions, and therefore perhaps even life.
The discovery, hidden from satellite scanners, raises another time Samples taken by the Rover of Perseverance are brought to earth, scientists can find evidence that ancient life has prospered once on our neighbor now deactivated. The researchers published their results on April 17 in the journal Science.
“When it has become obvious that these rocks contained siderite in such high quantities, I was incredibly excited”, study author Ben TutoloAn associate professor in the Department of Earth, Energy and Environment of the University of Calgary, told Live Science. “One of the biggest questions in Mars Science is:” Where are all carbonates? “So I knew immediately at what extent this discovery was important.”
Over the past 4 billion years, the Earth’s carbon cycle has been the key to its habitability – the carbon by bicycle between the atmosphere, the earth and the ocean, thus providing the key material to all living beings and fixing the atmospheric thermostat so that they prosper. The slow carbon cycle represents half of this system. Cracking in volcanoes, carbon dioxide is absorbed by the oceans rich in calcium to form a limestone rock which is subdued in the coat, heated and released once again.
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However, despite Mars showing many signs that Ancient rivers and lakes Once growing on the planet, neither the Rovers nor the satellite scans had found proof of carbonate minerals that would involve a carbon cycle there.
The discovery of the Rover Curiosity changes it all. Landing on the Gale Crater in March in 2012, the Rover traveled 21 miles (34 kilometers) of the meteor impact crater 96 miles wide (154 km), conscientiously investigating geology inside. In 2022 and 2023, Curiosity pierced four rock samples in the crater and analyzed mineralogy using its on -board X -ray diffractometer before bringing the results to the ground.
When Tutolo and his colleagues unpacked this analysis, they found that the rocks did not only contain traces of siderite, they were rich – representing between 5% and 10% of the total weight of the sample. The other minerals were other minerals, in particular the highly soluble soluble magnesium sulfate salts, which, according to the researchers, act to “hide” the signal of the siderite of satellite scanners.
“Because similar rocks containing these salts have been identified worldwide, we deduce that they also probably contain abundant carbonate minerals,” said Tutolo. “The summons of carbonate that all these deposits probably contain indicates that they can hold a substantial part of the CO2 which was once involved in the warming of March.”
A “unbalanced” cycle
The researchers believe that if their sample is representative of the whole planet, it probably indicates that Mars has a “unbalanced” carbon cycle. As Mars apparently lacked the tectonics of earth type plates, towards the end of its habitability, Mars probably recycled its carbon in its atmosphere by chemical reactions with acid water, a hypothesis supported by the presence of minerals of sulfate and iron oxide found in the sample.
But this process was heavy, pulling more carbon dioxide out of the atmosphere and in the rocks it did not relax. In the long term, this has decreased the planet’s ability to support an atmosphere, possibly stifled the ancient life in March at the same time, it began to flourish on earth.
“Life may have been formed at that time. Our oldest fossils are around 3.5 billion years and life must have been formed before that,” Janice BishopA principal researcher in search of the Extraterrestrial Intelligence Institute (SETI) and the author of a Piece of perspective that accompanies it On the study, said live. “While atmospheric gases (on Mars) were lost over time, the atmosphere has become thinner and the planet has become colder. Estimates of surface ages indicate that Mars has been cold and dry for at least 2 billion years.”
Other revelations will not come from a direct recovery of the samples taken from the surface of Mars so early – this mission is significantly on the budget and delayed. But curiosity should continue to explore the Martian surface to understand how the rocks have formed, and what it can be included in the simulations of the old climate of the planet.