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Samantha Shen
ECS NEWS
NASA Says Rock Samples Are The ‘Closest’ We’ve Come To Finding Ancient Life On Mars
Sanjeev Gupta, a planetary scientist from Imperial College London and one of the authors of a study on the Martian rocks, told the BBC, “We’ve not had something like this before, so I think that’s the big deal. We have found features in the rocks that if you saw them on Earth could be explained by biology – by microbial process. So we’re not saying that we found life, but we’re saying that it really gives us something to chase.”
Rock samples discovered by NASA Perseverance Rover are “the closest we’ve actually come to discovering ancient life on Mars,” according to acting NASA Administrator Sean Duffy. Based analysis of the markings on the rocks, scientists believe they contain minerals that may be a byproduct of microbes seen on Earth.
While scientists won’t rule out the markings being caused by natural geological processes, they are significant enough for NASA to consider them to be potential biosignatures. “A potential biosignature is a substance or structure that might have a biological origin but requires more data or further study before a conclusion can be reached about the absence or presence of life,” NASA explained.
“The identification of a potential biosignature on the Red Planet is a groundbreaking discovery, and one that will advance our understanding of Mars,” said Duffy.
“Getting such a significant finding as a potential biosignature on Mars into a peer-reviewed publication is a crucial step in the scientific process because it ensures the rigor, validity, and significance of our results,” said Katie Stack Morgan, Perseverance’s project scientist at NASA’s Jet Propulsion Laboratory.
Analysis by the Perseverance Rover revealed that the sedimentary rocks are composed of clay and silt, “which, on Earth, are excellent preservers of past microbial life,” NASAwrote. The rocks also “appear to have formed by electron-transfer reactions between the sediment and organic matter,” which “is a potential fingerprint for microbial life.”
NASA does admit that they could have been created on other ways, such as sustained high temperatures, acidic conditions, and binding by organic compounds, but the rocks don’t show any evidence of that being the case.
“That’s part of the reason why we can’t go so far as to say, ‘A-ha, this is proof positive of life,’’’ lead researcher Joel Hurowitz of Stony Brook University told The Associated Press. “All we can say is one of the possible explanations is microbial life, but there could be other ways to make this set of features that we see.”
Either way, Hurowitz said it’s the best, most compelling candidate yet in the rover’s search for potential signs of long-ago life. It was the 25th sample gathered; the tally is now up to 30. The findings appeared in the journal Nature.
“It would be amazing to be able to demonstrate conclusively that these features were formed by something that was alive on another planet billions of years ago, right?” Hurowitz said. But even if that’s not the case, it’s “a valuable lesson in all of the ways that nature can conspire to fool us.”
Along with organic carbon, a building block of life, Hurowitz and his team found minuscule specks, dubbed poppy seeds and leopard spots, that were enriched with iron phosphate and iron sulfide. On Earth, these chemical compounds are the byproducts when microorganisms chomp down on organic matter.
“There is no evidence of microbes on Mars today, but if any had been present on ancient Mars, they too might have reduced sulfate minerals to form sulfides in such a lake at Jezero Crater,” Bishop and Parente wrote in an accompanying editorial.
There’s no evidence of present-day life on Mars, but NASA over the decades has sent spacecraft to Mars in search of past watery environments that might have supported life way back when.
When Perseverance launched in 2020, NASA expected the samples back on Earth by the early 2030s. But that date slipped into the 2040s as costs swelled to $11 billion, stalling the retrieval effort.
Until the samples are transported off of Mars by robotic spacecraft or astronauts, scientists will have to rely on Earthly stand-ins and lab experiments to evaluate the feasibility of ancient Martian life, according to Hurowitz.
NASA’s acting Administrator Sean Duffy said budgets and timing will dictate how best to proceed, and even raised the possibility of sending sophisticated equipment to Mars to analyze the samples on the red planet. “All options are on the table,” he said.
Ten of the titanium sample tubes gathered by Perseverance were placed on the Martian surface a few years ago as a backup to the rest aboard the rover, all part of NASA’s still fuzzy return mission.
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