This Is The Closest NASA Has Ever Come To Discovering Life On Mars

We've discovered a lot of strange things on Mars, but thus far, conclusive proof of life on the red planet has eluded us. Now, however, NASA has come as close as it ever has to confirming that Mars did, at one time, host living organisms. The agency's Perseverance rover was sent to collect samples from Mars back in 2020 and, as detailed in a new study published in the journal Nature, four years later it came across rocks that formed part of a long dormant riverbed and which look to have contained elements that could have supported microbial life.

While there has never been any proof of Mars having hosted life, NASA missions have yielded convincing evidence the planet was, at one point billions of years ago, a much warmer and wetter environment and that it actually had an atmosphere(today, Mars has an extremely thin atmosphere with only trace amounts of oxygen). As such, when we talk about life on Mars, we're talking about evidence of living organisms that died out long ago. Now, the Perseverance rover has come closer than ever to finding that evidence.

The rover examined material around an area known as Jezero Crater and identified a rock dubbed "Cheyava Falls," which formed part of a rocky outcrop called Bright Angel. The rover then took a sample of the rock before onboard instruments were used to identify clay and silt, which are known on our own planet to be ideal for the preservation of microbial life. The rock also contained organic carbon, sulfur, oxidized iron (rust), and phosphorous, which could have provided the perfect environment for this early form of life.

Based on everything experts have observed, it seems likely that terrestrial life may not have started on Earth. We have, for example, discovered the building blocks of life on asteroids, but the closest place we've been able to identify as potentially hosting organisms at one point is Mars. A 2024 NASA study indicated there could be an exciting secret held within Martian ice, detailing the likely existence of microbes held beneath the planet's surface. But this latest discovery in a former Martian riverbed — while it isn't conclusive proof — is the most convincing evidence yet of life having existed on the planet.

The Nature study, entitled "Redox-driven mineral and organic associations in Jezero Crater, Mars," details the discovery of the Cheyava Falls rock in July 2024. Found in an ancient river valley named Neretva Vallis which once fed the Jezero Crater lake, the rock had leopard spots clearly visible on its surface. These spots were patterns of minerals where chemical and physical reactions occurred, and upon closer inspection were found to contain two particularly interesting minerals: vivianite (hydrated iron phosphate) and greigite (iron sulfide). Both of these are known to exist on Earth around — and produced by — organic matter.

This discovery is being treated as what NASA has termed a "potential biosignature," which refers to any substance or structure that could have a biological origin. However, further study is required to confirm that origin, which could also be explained by nonbiological processes. However, what makes this discovery so noteworthy is that the rocks in question weren't found to display any evidence of having been exposed to high temperatures or acidic conditions, which would be required to produce the minerals found via non-organic means. In other words, it seems highly likely that the minerals found in Cheyava Falls were produced via organic processes, and therefore appear to be the best evidence we have of life on Mars yet.

Finding the most convincing proof of life on Mars yet is a big deal in and of itself. But there are several other reasons why this latest discovery is significant. For one thing, the Cheyava Falls sample and the results of the Perseverance's onboard analysis have now been submitted to — and published in — a peer-reviewed publication, which means everything has been vetted and reviewed by other experts in the field. That makes a non-organic explanation for the minerals found in the rock even less likely, though it can't be ruled out entirely.

There's also the fact that the rocks sampled by the rover were some of the youngest sedimentary rocks ever found. That's important because, prior to this, experts believed that older rocks would hold the keys to finding evidence of life on Mars, but the Cheyava Falls rock shows that, if the potential biosignature is legitimate, Mars may have been able to support life for longer than originally thought.

For now, further research is needed to rule out an inorganic origin for the minerals discovered in the rock. As associate administrator of the Science Mission Directorate at NASA, Nicky Fox said in a statement, "With the publication of this peer-reviewed result, NASA makes this data available to the wider science community for further study to confirm or refute its biological potential." That means we'll soon get even more input from experts as to whether this latest finding is in fact proof that we're not alone in the universe.