NASA's Perseverance rover has discovered complex macromolecular carbon exposed directly on the surface of a rock called Bright Angel in Jezero Crater. The finding came at an outcrop on the edge of an ancient river channel named Neretva Vallis, marking what researchers call the shallowest detection of organic matter on the Martian surface to date. Lead author Ashley E. Murphy from the Planetary Institute led the study of these samples.

The carbon detection came from SHERLOC, a UV Raman spectrometer mounted on the rover's robotic arm. Between sols 1180 and 1218, the instrument fired deep-ultraviolet lasers at four targets at Bright Angel. Three of them - Cheyava Falls, Apollo Temple, and Walhalla Glades - returned spectroscopic signatures of macromolecular carbon, specifically the graphitic band (G-band) indicating a cross-linked network of reduced carbon atoms.

This material resembles terrestrial kerogen, which on Earth forms almost exclusively from biological sources like fossilized microbes. However, the research team avoided using the term kerogen because it implies a biogenic origin. Instead, they refer to it as macromolecular carbon to acknowledge uncertainty about whether the Martian material has an abiotic or biotic source.

Determining the origin of this carbon will likely require bringing samples back to Earth through future missions. The discovery adds to growing evidence that Mars once hosted complex chemical processes, though whether these involved life remains unknown.