A recent study based on a core sample taken by Perseverance from a site called Sapphire Canyon in July 2024 described textures and minerals that, on Earth, often form through microbial processes.
The findings include circular reaction fronts known as “leopard spots” and mineral nodules within a fine-grained mudstone.
Two key minerals, vivianite and greigite, were detected alongside organic carbon in repeating chemical patterns.
“These findings by Perseverance are the closest we have ever come to discovering life on Mars,” said acting NASA Administrator Sean Duffy.
“The identification of a potential biosignature on the Red Planet is a groundbreaking discovery, and one that will advance our understanding of Mars.”
Researchers emphasized that nonbiological chemistry could also account for the signals.
Lead author Joel A. Hurowitz of Stony Brook University noted the cautious approach: “We cannot claim this is more than a potential biosignature.”
On Earth, vivianite typically forms in water-rich sediments influenced by microbial iron reduction, while greigite often appears in environments shaped by sulfate-reducing bacteria.
In the Martian sample, rims of vivianite surrounding greigite-rich cores mirrored electron transfer reactions seen in some Earth sediments.
The study underlined that such chemistry is compatible with life but not proof of it.
“(But) this very well could be the clearest sign of life that we’ve ever found on Mars,” Duffy added.
Nicky Fox, NASA’s associate administrator for science, reinforced the need for restraint, calling it “a potential biosignature, not proof of life.”
The rock, nicknamed “Cheyava Falls,” lies within Neretva Vallis, an ancient river channel that once fed water into Jezero Crater’s lake.
The sample remains sealed for possible return to Earth, where advanced laboratory testing could distinguish biological from nonbiological origins.
NASA scientists pointed to the Confidence of Life Detection (CoLD) scale as a framework for assessing such discoveries, stressing step-by-step validation to avoid premature claims.
While the findings represent a major advance in Mars exploration, further analysis is required before confirming life beyond Earth.