NASA’s rover Perseverance has uncovered rocks that may hold potential signs of ancient microbial life on Mars, according to research published Wednesday.
Since landing on the Martian surface in 2021, the rover has been searching for signs of ancient life in Jezero Crater, a region in the planet’s northern hemisphere that was once flooded and contained an ancient lake basin.
In summer 2024, Perseverance discovered newly identified “Sapphire Canyon” rock samples in the reddish, clay-rich mudstones of Neretva Vallis, a river channel that once carried water into Jezero Crater. The samples were then examined using all the scientific instruments aboard the rover.
NASA’s science mission chief, Nicky Fox, acknowledged that the latest analysis “is certainly not the final answer,” but said it’s “the closest we’ve actually come to discovering ancient life on Mars.”
What do scientists say?
Stony Brook University planetary scientist Joel Hurowitz, who led the study published in the journal Nature, said that researchers detected a “potential biosignature” in multi-billion-year-old sedimentary rocks.
These potential biosignatures took the form of two minerals that appear to have formed from chemical reactions between mud and the organic matter present in it, Hurowitz said.
The minerals are vivianite, an iron phosphate, and greigite, an iron sulfide. “These reactions appear to have taken place shortly after the mud was deposited on the lake bottom. On Earth, reactions like these, which combine organic matter and chemical compounds in mud to form new minerals like vivianite and greigite, are often driven by the activity of microbes,” Hurowitz explains.
Vivianite is often found in sediments and peat bogs on Earth, as well as in areas with decaying organic matter. Some forms of microbial life can produce greigite. “The microbes are consuming the organic matter in these settings and producing these new minerals as a byproduct of their metabolism,” he added..
More study needed on Earth
Although scientists cannot say with certainty that they have found signs of ancient microbial life, they consider the findings to be convincing.
“It’s kind of the equivalent of seeing like leftover fossils, you know, leftovers from a meal, and maybe that meal has been excreted by a microbe. And that’s what we’re seeing in this sample,” Nicky Fox, administrator of NASA’s Science Mission Directorate, told journalists.
Hurowitz explained that researchers would need to analyze the sample in person to determine whether microbial activity had created the fantastic textures and colors, including blue and green.
Ideally, this analysis would be conducted in labs on Earth before drawing any conclusions. “There are non-biological ways to make these features that we cannot completely rule out on the basis of the data that we collected,” Hurowitz said.
However, bringing the samples back to Earth could be challenging, especially since the Trump administration is considering canceling the Mars Sample Return program.
According to Hurowitz, until samples are transported off Mars by robotic spacecraft or astronauts, scientists will have to rely on earthly stand-ins and laboratory experiments to evaluate the feasibility of ancient Martian life..
Edited by: Louis Oelofse
