The latest evidence comes from a tool called Sherlock that’s mounted on the six-wheeled rover’s robotic arm and that enables detailed mapping and analysis of organic molecules. Researchers are reporting Sherlock’s findings from 10 sites in two geological formations on the floor of Jezero Crater.
They obtained evidence indicating the presence of organic molecules in multiple rock samples, including some collected for possible return to Earth for future analysis. The researchers note that evidence of such molecules is not evidence of past or present life on Mars, and that non-biological processes remain a more likely explanation.
molecular building blocks
“Organic materials are the molecular building blocks of life as we know it, but they can also form from geological processes that are not directly related to life. We see multiple signals that appear to vary across crater floor formations and in associated minerals. nature.
Perseverance, on a mission to search for evidence of ancient life on Mars and collect rock and soil samples for possible return to Earth, Landed Feb 2021 in Jezero Crater, an area in the planet’s northern hemisphere that was once flooded and home to an ancient lake basin.
Mars wasn’t always the inhospitable place it is today, with liquid water on its surface in the distant past. Scientists believe that microbial life could have inhabited Jezero Crater. They believe river channels ran over the crater wall and created the lake more than 3.5 billion years ago.
Signals of organic molecules were detected in all 10 of the places Sherlock studied — short for Surveying Habitable Environments Using Raman and Luminescence for Organic Materials and Chemicals — on the crater floor. The rocks were igneous – volcanic.
Sherloc uses cameras, lasers, and instruments called spectrometers that analyze wavelengths of light to search for organic molecules that may be signs of microbial life in the past. Joining the theme of Sherlock Holmes, Sherlock Watson assists, a color camera to get close-up images of rock grains and surface textures.
clues
Researchers don’t know the specific organic compounds Sherlock discovered, but they do have some clues. The chemical signatures can come from compounds such as benzene or naphthalene, said study co-author Ryan Rubel, a graduate student in chemistry at the University of Pittsburgh.
“On Earth, these are very common in crude oil, which has a biological origin, but we can also form them synthetically through various chemical reactions,” Rubel said.
“The concentrations we’ve detected are generally low, but we’ve noticed signals associated with organics on nearly every rock we’ve sampled,” Rubel added.
Ruppel said the researchers cannot rule out that inorganic sources — the mineral — could be responsible for some of the signals that point to the presence of organic molecules.
Signs of organic molecules were first detected on Mars in 2015 by a different rover, Curiosity, and more evidence followed in subsequent years. With Perseverance now detecting potential signatures of organic molecules, evidence is accumulating that organic molecules may be relatively common on Mars, albeit at low levels.
The researchers remain cautious about the results.
There are biotic and abiotic mechanisms that can form organic molecules. Rubel said that interplanetary dust, friction from meteorites or hydro-rock interactions can produce organic materials abiotically. “On the other hand, ancient life could have produced these organics as well, but this is generally a hypothesis of last resort. We need to rule out all abiotic mechanisms before we jump to the conclusion that any organic molecule is a sign of life.”
(Reporting by Will Dunham).
