Taking a new look at a very old mudstone on Mars, scientists believe they have found a potential biosignature, indicating that Mars may have once hosted life. In July of 2024, while exploring an old, dried up river bed on the edge of Jezero Crater, NASA's Perseverance rover happened upon an odd-looking rock.

"When we see features like this in sediment on Earth, these minerals are often the byproduct of microbial metabolisms that are consuming organic matter."