Is it true that Mars has life?

In July 2024 the Perseverance rover analyzed, inside Jezero crater, an arrowhead-shaped rock named Cheyava Falls. It was located in the Bright Angel formation, in the ancient river valley of Neretva Vallis. The extracted sample, called Sapphire Canyon, showed a striking pattern: minerals arranged along reaction fronts, with vivianite — a hydrated iron phosphate — and greigite, an iron sulfide. The rover, which landed on Mars in February 2021, had been searching ever since for records of this kind in a crater that once held water.

NASA defines a potential biosignature as a substance or structure that could have a biological origin but requires more data or further study before reaching a conclusion. The team published the results in the journal Nature on September 10, 2025, after a year of scrutiny, and its wording is deliberately cautious: abiotic explanations for what was observed at Bright Angel seem less likely, but cannot be ruled out. It is not a discovery of life; it is a clue that calls for further investigation.

Curiosity contributes the other half of the case file from Gale crater. In the Cumberland sample, drilled at Yellowknife Bay in 2013 and dated at around 3.7 billion years old, decane, undecane and dodecane were identified: organic molecules with ten, eleven and twelve carbon atoms, the largest detected on Mars so far. Caution rules here too, because fatty acids can form without life, through geological reactions such as water interacting with minerals in hydrothermal vents. What has been demonstrated is that ancient Mars had the chemistry needed for life; what is still missing, and it is no small thing, is proof that this chemistry ever took that step.