NASA’s Perseverance rover has discovered a “biosignature”—a possible sign of ancient microbial life—in a rock sample from Mars’s Jezero Crater. The finding, published in the journal Nature, includes a combination of minerals and organic matter that, on Earth, are often produced by microbes. The potential biosignature might have a biological origin, but the discovery needs detailed study before reaching the conclusion regarding the presence or absence of life.
Scientists emphasize that non-biological processes could also explain mineral formation, though the evidence does not point to the high-temperature conditions typically required for such chemical reactions to occur without life. The sample, nicknamed “Sapphire Canyon,” was collected in 2024 from a mudstone rock formation called Cheyava Falls within the Neretva Vallis, an ancient river channel that flowed into the Jezero river.
Analysis by the rover’s instruments revealed unusual “leopard spots”—colorful speckles and rings enriched with iron phosphate (vivianite) and iron sulfide (greigite), alongside carbon. On Earth, vivianite and greigite often form at low temperatures in water-rich sedimentary environments where microbes metabolize organic matter. The arrangement of these organic minerals on Mars resembles the byproducts of this type of microbial activity.
The discovery highlights that ancient Mars had potentially habitable conditions, suggesting life may have once existed for a longer period than previously thought. However, the mission faces budget and timeline uncertainties. It also underscores the importance of the ongoing effort to return Martian samples to Earth for conclusive study.