There may still be evidence of life on Mars – but the possibility of that evidence inside a 4-billion-year-old meteorite that crashed to Earth decades ago is getting slimmer.
The organic compounds in the rock formed 4 pounds of water, possibly brackish or hypersaline, flowing through the meteorite, according to a study published Thursday in the journal Science.
Organisms did not leave the compounds there, as an earlier theory hypothesized. The presence of the compounds in the rock suggests that the Red Planet is capable of creating the chemistry that could lead to life, said Andrew Steele, an astrobiologist at the Carnegie Institution for Science who led the multinational team of scientists that conducted the study.
“The results are very positive,” Dr. Steele said in an interview. “What we found is an abiotic chemical reaction that makes the building blocks of life.”
The rock, believed to have bounced off the surface of Mars into outer space billions of years ago, was found in Antarctica in 1984. A team of NASA-led scientists who spent years analyzing it announced in 1996 that it appears to hold clues to ancient Martian life — a A theory that has lost its appeal to some researchers over time as technology improves and scientists extract more accurate data.
Dr. Steele’s team used minute sample slices – often smaller than a strand of human hair – to identify and analyze the carbon-rich compounds, which were created when water flowed through hot rocks billions of years ago and interacted with meteorite minerals.
He said the study’s findings offer a tantalizing look at similar reactions that may have been occurring around the same time on Earth and may help the ongoing search for evidence of extraterrestrial life.
Pointing to Mars, Enceladus and Europa, Dr. Steele said, the moons of Saturn and Jupiter have subsurface oceans.
Dr. Steele said he is eagerly awaiting the collection of more Martian samples, which will be returned to Earth for further study in the coming years.
The National Aeronautics and Space Administration launched its Persevering Mars rover from Florida on July 30, 2020. The wheeled robotic rover landed last February near the crater of Mars known as Jezero. Its job is to search for signs of past life that may have been around the crater, which was once a lake.
After sufficient samples are collected, the cargo will be transported to Earth on two different missions scheduled to arrive around 2030, according to Dr. Steele.
NASA did not respond to a request to speak with the scientists who conducted a 1996 study of the meteorite, which was named Allan Hills 84001 in reference to where it was found.
Dr. Steele said that although his latest work does not support all of those initial findings, the 1996 study was significant to the field at large.
“The 1996 team inspired, catalyzed funding, made finding life a public mission, and created a generation of upcoming students who are participating in this important debate,” he said.
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It appeared in January 15, 2022, print edition as “Meteorite Shows No Sign of Life on Mars, Study Says.”