Mars rock holds ancient life signs

Scientists believe the intriguing leopard spots on a rock sampled by the Perseverance rover on Mars last year may have potentially been made by ancient life, NASA announced Wednesday. The team has also published a peer-reviewed paper in the journal Nature about the new analysis, though they say further study is needed.

According to the report, the sample, called Sapphire Canyon, was collected by the Perseverance rover from rocky outcrops on the edges of the Neretva Vallis river valley, a region sculpted by water that once flowed into Jezero Crater more than 3 billion years ago.

The rover landed within the crater to explore the ancient lake site in February 2021, seeking rocks created or modified by water on Mars in the past. Perseverance drilled the Sapphire Canyon sample from an arrowhead-shaped rock called Cheyava Falls in July 2024.

Acting NASA Administrator Sean Duffy said, “After a year of review, they have come back and said, listen, they cannot find another explanation.” He added, “So this very well could be the clearest sign of life that they’ve ever found on Mars, which is incredibly exciting.”

Perseverance project scientist Katie Stack Morgan said, “The discovery of a potential biosignature, or a feature or signature that could be consistent with biological processes, but that requires further work and study to confirm a biological origin is something that they’re sharing with the public today.”

The new announcement is the result of a long, peer-reviewed research process and the collection of more data, said lead study author Joel Hurowitz, a planetary scientist at Stony Brook University in New York. The research team conducted a thorough analysis, and Joel Hurowitz emphasized the importance of this step in the scientific process.

Peer review and publication are crucial steps in the scientific process that allow NASA to make the mission data and the science team’s interpretation of that data available to the broader science community for further study, said Lindsay Hays, senior scientist for Mars Exploration at NASA’s Planetary Science Division. It enables the team to share their findings and get feedback from other experts.

According to the report, the Perseverance rover surveyed the river valley after finding the sample to better understand the environment where the rocks were deposited and determine how the leopard spots may have formed. The rover’s findings provided valuable insights into the geological context of the sample.

Nicky Fox, associate administrator for NASA’s Science Mission Directorate, said, “Today, they are one step closer to answering humanity’s most profound questions, including whether they are truly alone in the universe.” The discovery is a significant milestone in the search for life beyond Earth.

The features on the rock are likely due to the presence of ferrous iron phosphate and iron sulfide, or the minerals vivianite and greigite, according to the researchers. Typically, these minerals form in environments with a low temperature and the presence of water, such as those found on gas giants.

Dr. Michael Tice, a geobiologist and astrobiologist in the department of geology and geophysics at Texas A&M University, said, “On Earth, things like these sometimes form in sediments where microbes are eating organic matter and ‘breathing’ rust and sulfate.” The team considers this process as a possible explanation for the formation of the leopard spots.

In the study, the authors explore two potential scenarios for how the rock features formed: due to the presence of life or without it. While it’s possible that some of the features could be produced strictly geochemically due to reactions between organic matter and iron, that process usually only works at relatively high temperatures — something the team does not see evidence of. They must consider alternative explanations, including the role of online data in their research.

Joel Hurowitz acknowledged that there are nonbiological ways to create features like the leopard spots. He said, “What they need to do from here is to continue to do additional research in laboratory settings here on Earth, and ultimately bring the sample from this rock back home to Earth, so that they can make the final determination for what process actually gave rise to these fantastic textures.” The team plans to conduct further analysis to determine the origin of the features.

Scientists are still in the process of analyzing the geologic context of the sample, but the new paper represents an overview of how they currently understand the Cheyava Falls rock, Katie Stack Morgan said. More papers are expected over the next year or so, and the researchers will continue to refine their understanding of the sample. The team’s findings may have implications for the design of future electronic systems, including those used in electronic design.

The Perseverance rover has been collecting samples along the way that were intended to be returned to Earth by future missions. However, it’s currently unclear how NASA would return the samples to Earth as the agency grapples with the White House’s proposal to slash NASA’s science budget by as much as half.

According to the report, Acting NASA Administrator Sean Duffy said, “They’re looking at how to get the sample back, or other samples back.” He added, “What they’re going to do is look at their budgets, they look at their timing, and determine how to spend money better, and what technology they have to get samples back more quickly?” The agency is exploring options for returning the samples to Earth.