NASA’s Perseverance rover may have found one of the most significant signs of ancient life ever seen on Mars. In a paper published in the journal Nature, scientists revealed that a rock sample collected by the rover in 2024 contains a mixture of minerals and organic carbon that they are calling a “potential biosignature.” While researchers are stressing that this is not definitive proof of Martian microbes, acting NASA Administrator Sean Duffy called it potentially “the clearest sign of life that we’ve ever found on Mars.”
Leopard spots in a Sapphire Canyon
The discovery centers on a rock core sample named “Sapphire Canyon,” which Perseverance drilled from a rock dubbed “Cheyava Falls” in July 2024. The rock, located in Mars’ Jezero Crater within a formation called “Bright Angel,” immediately caught scientists’ attention due to its peculiar texture, featuring dark specks described as “poppy seeds” scattered among larger “leopard spots.” Using the rover’s onboard instruments, including the PIXL and SHERLOC spectrometers, the team identified a compelling chemical cocktail.
The spots contained two iron-rich minerals: vivianite and greigite. On Earth, these minerals are often linked with biological activity. NASA notes that vivianite is frequently found in sediments near decaying organic matter, and certain microbes can produce greigite as a byproduct of their metabolism. The combination of these minerals with the organic carbon also found in the rock suggests a chemical reaction that living organisms could have used for energy.
Life, or just some very interesting chemistry?
Despite the excitement, NASA is exercising extreme caution. A “potential biosignature” is a major step, but it’s not a fossil. The minerals could have formed through non-biological, or abiotic, processes. As Joel Hurowitz, the study’s lead author, told Reuters, “we cannot rule those processes out completely on the basis of rover data alone.”
However, the case for a biological origin is strengthened by what’s missing. The typical abiotic pathways for creating these minerals involve high temperatures or highly acidic conditions, but the rocks at Bright Angel show no evidence of having experienced either. While it’s still possible the minerals formed without life, the findings make abiotic explanations “less likely,” according to Perseverance project scientist Katie Stack Morgan. The discovery is also surprising because it was made in relatively young sedimentary rocks, suggesting Mars may have been habitable for longer than previously believed.
Now comes the 40-million-mile wait
Ultimately, the rover’s onboard instruments have reached their limit. To know for sure if the spots in the Sapphire Canyon sample are a residue of ancient Martian life, scientists need to analyze the rock in advanced laboratories on Earth. That’s the entire goal of the Mars Sample Return (MSR) mission, a complex campaign designed to retrieve the 30-plus samples Perseverance has collected.
There’s just one problem: the MSR mission is in limbo. Citing rising costs and scheduling delays, funding for the program has been a point of contention, with President Trump’s recent budget proposal seeking to cancel the existing plan. While NASA is exploring lower-cost alternatives, the fate of the samples — including the one that might just rewrite biology textbooks — currently hangs in the balance. As officials told reporters, getting the sample home is the only way to truly solve this Martian mystery.
Sources
- NASA says its Mars rover may have found evidence of ancient life
- NASA Says Mars Rover Discovered Potential Biosignature Last Year
- Perseverance’s PIXL Finds Vivianite, Greigite in Cheyava Falls Sample
- NASA rover finds potential sign of ancient life in Martian rocks
- Perseverance rover finds potential sign of ancient life in Martian rock
- Researchers detail latest findings from NASA’s Perseverance rover exploring Mars’ Jezero crater
- Redox reactions with organic carbon in a Martian mudstone
