The study highlights minerals and textures that, on Earth, are often associated with microbial activity.
A rock sample collected by NASA’s Perseverance rover from an ancient riverbed in Jezero Crater may hold evidence of past microbial life on Mars. The discovery, described in a paper published in Nature, marks the closest scientists have come to identifying signs of life on the Red Planet.
The sample, called “Sapphire Canyon,” was extracted last year from a rock dubbed “Cheyava Falls” in the “Bright Angel” formation, a region of rocky outcrops bordering the ancient Neretva Vallis river valley.
“This finding by Perseverance, launched under President Trump in his first term, is the closest we have ever come to discovering life on Mars. The identification of a potential biosignature on the Red Planet is a groundbreaking discovery, and one that will advance our understanding of Mars,” said acting NASA Administrator Sean Duffy. “NASA’s commitment to conducting Gold Standard Science will continue as we pursue our goal of putting American boots on Mars’ rocky soil.”
Scientists stress that what Perseverance uncovered is a potential biosignature—defined as a substance or structure that might have a biological origin but requires further analysis to confirm. Sedimentary rocks at Bright Angel were found to be rich in clay, silt and organic carbon, as well as sulfur, oxidized iron and phosphorus—elements that, on Earth, often preserve signs of ancient life and provide energy for microbial metabolisms.
The rover’s PIXL and SHERLOC instruments first detected colourful markings on Cheyava Falls, a meter-long arrowhead-shaped rock. High-resolution scans revealed “leopard spots,” distinct mineral patterns formed by vivianite and greigite, compounds associated with decaying organic matter and microbial activity on Earth. These minerals can form through biological processes such as electron-transfer reactions but also via abiotic mechanisms like extreme heat or acidity. The Bright Angel rocks show no evidence of such conditions, leaving biological activity as a possible explanation.
“The combination of chemical compounds we found in the Bright Angel formation could have been a rich source of energy for microbial metabolisms,” added Perseverance scientist Joel Hurowitz of Stony Brook University, New York and lead author of the paper. “But just because we saw all these compelling chemical signatures in the data didn’t mean we had a potential biosignature. We needed to analyze what that data could mean.”
The study’s findings are particularly striking because the rocks are among the youngest sedimentary formations studied by the mission, suggesting Mars may have remained habitable longer than previously thought. Perseverance project scientist Katie Stack Morgan emphasized the importance of scientific rigor in evaluating astrobiological claims. “Getting such a significant finding into a peer-reviewed publication is a crucial step,” she said. “While abiotic explanations are less likely, we cannot rule them out.”
To guide interpretation, researchers apply frameworks such as the CoLD scale and Standards of Evidence, which help assess how much confidence can be placed in data suggesting life beyond Earth.
Since its landing in February 2021, Perseverance has collected 27 rock cores, including Sapphire Canyon, while also monitoring the Martian environment and testing spacesuit materials for future crewed missions. Operated by NASA’s Jet Propulsion Laboratory and managed through Caltech, the rover is part of the agency’s broader Mars Exploration Program.
Nicky Fox, associate administrator of NASA’s Science Mission Directorate, said the discovery was the result of careful mission planning and execution. “With the publication of this peer-reviewed result, NASA makes this data available to the wider science community for further study to confirm or refute its biological potential,” she said.