NASA may have found its most compelling evidence yet that Mars once supported life. A sample collected by the Perseverance rover shows chemical signatures and textures resembling those left behind by microbes on Earth.
The discovery does not confirm that Mars once hosted living organisms, but scientists say it is the clearest lead so far. The findings underscore both the promise and the challenge of unraveling the Red Planet’s history, with answers now hinging on whether the sample can be brought back to Earth for further study.
What NASA discovered in Jezero Crater
What we know:
Perseverance drilled into a mudstone outcrop in Jezero Crater’s ancient river valley in the summer of 2024. The rock, part of a formation called Bright Angel, contains reddish, clay-rich layers that formed billions of years ago when water once flowed through the crater.
Within the sample, researchers identified tiny dark specks—nicknamed “poppy seeds” and “leopard spots”—enriched with iron phosphate and iron sulfide. On Earth, these minerals commonly appear as byproducts when microbes interact with organic matter in wet, low-oxygen environments. The sample also contains organic carbon, one of life’s building blocks.
“This is the closest we’ve actually come to discovering ancient life on Mars,” NASA science mission chief Nicky Fox said. Still, researchers caution the evidence is not definitive.
What we don’t know:
Scientists stress that the features could have formed without biology. Nonliving chemical reactions might also explain the minerals and textures. Lead researcher Joel Hurowitz of Stony Brook University said the results should be viewed as a possibility, not proof.
“All we can say is one of the possible explanations is microbial life,” Hurowitz told the Associated Press. “But there could be other ways to make this set of features that we see.”
A view of Mars showing its cratered surface and thin atmosphere, captured by a spacecraft in orbit around the Red Planet. NASA scientists say ancient river valleys and mineral deposits point to a wetter past that may have supported life. (Photo by © CORBIS/Corbis via Getty Images)
Previous discoveries that paved the way
The new finding builds on decades of Mars exploration. NASA’s Curiosity rover, which has been exploring Gale Crater since 2012, discovered evidence of ancient lakes and streams, along with carbonate minerals that point to a thicker atmosphere in the planet’s past.
Earlier missions, including the Spirit and Opportunity rovers and orbiters such as Mars Reconnaissance Orbiter, found river valleys, deltas and mineral deposits showing that water once covered large parts of Mars. These discoveries established that the planet was once much wetter and more hospitable, setting the stage for Perseverance’s mission in Jezero Crater.
Why the Mars rock sample could point to past microbes
Big picture view:
If confirmed, the discovery would represent the first evidence of life beyond Earth. Even if the textures turn out to have nonbiological origins, they provide valuable lessons about how planetary processes can mimic signs of life.
The findings also raise the stakes for NASA’s Mars Sample Return mission. The program aims to bring Perseverance’s cache of drilled rock cores—now totaling about 30—back to Earth for detailed laboratory analysis.
What’s next:
NASA originally aimed to return the samples by the early 2030s, but cost overruns and technical hurdles have pushed that timeline into the 2040s. The price tag has ballooned to around $11 billion, prompting officials to explore cheaper and faster alternatives.
Options now under discussion include sending more advanced instruments to Mars for on-site analysis or adjusting the return plan to reduce costs. NASA officials say all options remain on the table.
For now, the rover continues to explore Jezero Crater, collecting samples from sites most likely to preserve signs of past habitability. Ten backup sample tubes have already been placed on the Martian surface as insurance against rover failure.
Whether analyzed on Mars or someday in labs on Earth, the sample from Jezero Crater’s Bright Angel formation is now viewed as one of the strongest candidates in the search for ancient life beyond our planet.
The Source: This report is based on findings published in the journal Nature, statements from NASA officials, and interviews with mission scientists including Joel Hurowitz. Additional commentary was provided by researchers from the SETI Institute and the University of Massachusetts Amherst.