NASA’s Perseverance rover has uncovered compelling new evidence that Mars may once have harboured microscopic life. The discovery centres on clay-rich mudstone samples collected from the dry river channel Neretva Vallis, within the Bright Angel formation in Jezero Crater. Scientists found organic carbon, iron phosphate and iron sulfide minerals compounds that, on Earth, often form through biological processes. Also observed were small nodules and “leopard-spot” textures in the rock that defy simple geological explanations. Despite these striking signs, researchers emphasise the evidence is not definitive proof of past life.

Non-biological chemical processes might yet explain the features.The sample is one of more than 30 collected by Perseverance, and scientists hope that returning it to Earth currently expected in the 2040s will allow more detailed laboratory analysis. Meanwhile, this finding represents the strongest candidate so far for signs of ancient life on Mars.