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Evidence of ancient life may have been cleansed from parts of March, revealed a new study from NASA.
The space agency Curiosity The rover made the surprising discovery while investigating clay-rich sedimentary rocks around its landing site in Gale Crater, an ancient lake created when an asteroid hit the Red Planet about 3.6 billion years ago. ‘years.
Clay is a good indicator of evidence of life, as it is typically created when rock minerals erode and rot after contact with water – a key ingredient in life. It is also an excellent material for storing microbial fossils.
Related: Here’s what NASA’s Opportunity rover saw before the lights went out
But when Curiosity took two samples of ancient mudstone, a sedimentary rock containing clay, from patches of the dry lake bed, dated to the same time and place (3.5 billion years ago). and only 400 m apart), the researchers found that one plot contained only half the expected amount of clay minerals. Instead, this patch contained a greater amount of the iron oxides, the compounds that give Mars its rusty hue.
The team believe the culprit behind this act of geological disappearance is brine: super-salty water that has seeped into layers of mineral-rich clay and destabilized them, flushing them out and wiping patches at the same time. geological and perhaps even biological.
“We thought that once these layers of clay minerals formed at the bottom of the lake in Gale Crater, they stayed that way, preserving the time when they formed over billions of years,” said the Lead author of the study, Tom Bristow, a researcher at NASA’s Ames Research Center in Mountain View, California, said in a press release. “But later, brines destroyed these clay minerals in some places, essentially resetting the rock record.”
The rover completed its analysis by drilling into layers of Martian rock before using its chemistry and mineralogy instrument, known as the CheMin, to study the samples.
The process of chemical transformation in the sediment is called diagenesis, and it could have created new life under Mars even as it erased some of the evidence of old life on its surface, according to the study’s authors. So even though ancient records of life may have been erased from the brine plates, the chemical conditions caused by the influx of salt water may have allowed more life to arise in its place, said the scientists.
“These are great places to look for evidence of ancient life and assess habitability,” study co-author John Grotzinger, professor of geology at the California Institute of Technology, said in the release. “Even though diagenesis can erase the signs of life in the original lake, it creates the chemical gradients necessary to support life underground, so we’re really excited to have discovered this.”
Curiosity’s mission to Mars began nine years ago, but the rover has continued to study the Red Planet well beyond its initial two-year mission timeline, in order to establish the historic habitability of Mars for life. It is now working in conjunction with the new rover Perseverance Mars, which landed in February 2021 and has been tasked with collecting rock and soil samples for possible return to Earth.
Research by Curiosity not only revealed how the Martian climate has changed, but also helped Perseverance determine which soil samples to collect to increase the chances of finding life.
“We learned something very important: There are some parts of the Martian rock record that are not very effective in preserving evidence of the past and possible life on the planet,” co-author Ashwin Vasavada, scientist at the Project Curiosity at NASA’s Jet Propulsion Laboratory in California, said in the statement. “Luckily we find them both close to each other in Gale Crater and can use mineralogy to tell which is what.”
The search for life on Mars has been given new impetus thanks to a new study that could have triangulated the possible location of the six methane emissions detected by the Curiosity rover during its stay in Gale Crater, Live Science Reported. Since all of the methane in Earth’s atmosphere comes from biological sources, scientists are excited to find the gas on Mars.
The researchers published their results on July 9 in the journal Science.
Originally posted on Live Science.
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