In a groundbreaking discovery, NASA’s Perseverance rover has uncovered promising evidence that Mars may once have hosted microbial life. A rock sample retrieved from Jezero Crater, once thought to be a lakebed between 3.2 and 3.8 billion years ago, shows possible traces of biological processes.
While scientists caution that these findings do not confirm life, the discovery represents one of the most compelling indications yet that Earth’s planetary neighbor may have been habitable in its distant past.
Perseverance obtained a reddish rock sample named Sapphire Canyon in July 2024 from the Cheyava Falls outcrop in the Bright Angel rock formation. This site lies along the edges of Neretva Vallis, a channel carved by water flows that once fed the lake inside Jezero Crater.
NASA released an image of the collected mudstone rock—fine-grained, rusty-red in color—with distinctive ring-shaped and speckled features resembling leopard spots and poppy seeds. Researchers suggest these patterns may have formed through microbial chemical reactions during the rock’s early formation.
Joel Hurowitz, lead author of the study published in Nature and a scientist at Stony Brook University, confirmed that a “potential biosignature” was detected. He noted that the rock formed at a time when Jezero Crater was a watery environment.
Acting NASA Administrator Sean Duffy explained, “We can’t find another explanation, so this very well could be the clearest sign of life that we’ve ever found on Mars – which is incredibly exciting.”
However, NASA emphasized caution. Nicky Fox, associate administrator for NASA’s Science Mission Directorate, reminded the public: “It’s not life itself.”
Two specific minerals were detected in the Sapphire Canyon core:
Vivianite (iron-phosphorus mineral)
Greigite (iron-sulfur mineral)
According to Hurowitz, “These reactions appear to have taken place shortly after the mud was deposited on the lake bottom. On Earth, reactions like these … are often driven by the activity of microbes.”
The rover’s onboard instruments also identified high levels of organic carbon, sulfur, phosphorus, and oxidized iron. This chemical mix could have provided abundant energy for microbial metabolisms in Mars’ ancient environment.
While these findings resemble microbially driven processes on Earth, Hurowitz stressed that similar chemical reactions can occur without biology: “We cannot claim this is more than a potential biosignature … we cannot rule those processes out completely on the basis of rover data alone.”
Billions of years ago, Mars was not the dry, barren planet we see today. Evidence shows that liquid water flowed on its surface, forming rivers, lakes, and possibly even shallow seas. Jezero Crater, where Perseverance has been exploring since 2021, is widely regarded as one of the best sites to search for ancient Martian life due to its history as a lake basin fed by multiple river channels.
The true test of these biosignatures lies in bringing the Sapphire Canyon core sample back to Earth for detailed laboratory studies. As Hurowitz explained: “We can make a lot of progress on this question with laboratory experiments … but the ultimate tests can only be performed on the Sapphire Canyon core sample if and when it is brought back to Earth for study.”
Currently, the Mars Sample Return mission faces uncertainty. U.S. President Donald Trump’s budget proposal aims to cancel NASA’s planned retrieval project. Acting Administrator Duffy noted: “We’re going to look at our budgets and we’re going to look at our timing, and how we spend money better and what technology do we have to get samples back more quickly.”
This raises questions about the timeline for returning Martian rocks, though NASA continues to explore alternative strategies, including sending more advanced equipment directly to Mars.
NASA’s Perseverance rover has once again reshaped our understanding of Mars. The discovery of minerals and chemical compounds in Jezero Crater’s Sapphire Canyon sample provides one of the strongest indications yet that the Red Planet may have supported microbial life billions of years ago.
While scientists caution against premature conclusions, these findings highlight the importance of continued exploration and the urgent need for a sample return mission. Whether through future lab analysis on Earth or advanced in-situ studies, this discovery could eventually answer one of humanity’s most profound questions: Are we alone in the universe?