Evidence for possible life on Mars in the ancient past continues to build, thanks to a recent discovery by NASA’s Perseverance rover that identified complex carbon in two mudstones.
As detailed in a recent paper published in Science Advances, Perseverance collected samples in the Jezero crater, a location that has continued to yield possible biosignatures of life on Mars in the ancient past.
In the same region, scientists reported potential evidence of microbial activity on ancient Mars, adding to a growing list of circumstantial evidence for one of the most intriguing possibilities in modern space exploration: the prospect that Earth may not have been the only planet in our Solar System that has held the potential to host life.
A Prime Location for Life on Mars
Among the study’s most significant findings is that complex macromolecular carbon was discovered alongside other potential biosignatures. Jezero Crater, a 28-mile-wide impact basin on the Martian surface, once contained flowing water roughly 3.5 billion years ago, making it one of the most promising locations in the search for ancient life. Water is essential to all known life on Earth, serving as a universal solvent and playing a critical role in biological processes.
“Jezero Crater was selected as a landing site due, in part, to its past evidence of aqueous activity and potential to preserve organic material,” co-lead author Kyle Uckert, a research scientist at NASA’s Jet Propulsion Laboratory, told The Debrief. “The Perseverance Rover’s exploration of Jezero Crater helps us understand the past habitability of Mars.”
Perseverance targeted a distinctive geological feature known as the Bright Angel outcrop, where the samples were collected. The outcrop consists of mudstones deposited in the dry bed of an ancient river that once flowed into Jezero Crater. Comparable sedimentary deposits on Earth are often associated with environments capable of preserving evidence of microbial life.
Analyzing Samples
Determining the origin of the organic carbon preserved within these Martian rocks is key to understanding whether the Red Planet ever supported life.
Using its onboard Raman spectrometer, Perseverance mapped the distribution of the rocks’ organic matter. One sample contained organic carbon within a primary silicate-dominated matrix, while another preserved carbon within secondary carbonate and sulfate minerals.
Notably, the carbon appears to have remained remarkably well preserved despite billions of years of exposure to the harsh Martian environment. Researchers suggest its limited weathering may indicate that the material is resistant to radiation and oxidation—possibly because it is mixed with iron-rich regolith or protected by clay minerals—or that it was only recently exposed at the surface through erosion.
The researchers are quick to point out that their findings do not determine whether the carbon originated through biological or non-biological processes. Nevertheless, the discovery adds another intriguing piece of evidence to the ongoing search for ancient life on Mars.
“Macromolecular carbon may be delivered to Mars via meteorites, or may have formed through hydrothermal geologic processes,” Uckert said.
Continuing to Explore Life on Mars
According to the researchers, determining the true origin of the carbon will ultimately require returning Martian samples to Earth, where they can be examined using far more sophisticated laboratory instruments than those carried aboard Perseverance.
“Further constraining the origin, distribution, and alteration history of the MMC observed in the Neretva Vallis mudstones requires high-resolution and high-sensitivity analyses in terrestrial laboratories, which can be facilitated by the return of the Cheyava Falls rock core, ‘Sapphire Canyon’ to Earth,” explained co-lead author Ashley Murphy, a postdoctoral research scientist at the Planetary Science Institute.
“The Perseverance Rover science payload is not designed to determine whether martian organic molecules were created by biologic or geologic processes, and our study is unable to make this distinction,” Uckert added.
The researchers say that future sample-return missions, combined with advanced laboratory analyses on Earth, may finally help resolve one of planetary science’s most enduring questions.
“The Perseverance Rover collects samples of scientifically compelling martian rocks for potential return to Earth,” Uckert concludes.“Using high-resolution terrestrial instruments to analyze these rock samples, particularly the Sapphire Canyon core collected on the Cheyava Falls rock, may provide more compelling evidence for a biologic or abiotic origin of this organic matter.”
The paper, “Spatially Distributed Complex Organic Matter Detected in an Ancient River Valley in Jezero Crater, Mars,” appeared in Science Advances on June 24, 2026.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.