The NASA rover Perseverance has recently discovered complex carbon molecules within surface rocks on Mars. These molecules could, theoretically, be associated with ancient microbial life. This organic carbon was identified in fine-grained sedimentary rocks, specifically shale, at a location named Bright Angel, situated along what was once a riverbed feeding into Jezero Crater.
While this discovery is undoubtedly intriguing, it cannot yet be definitively declared as evidence of life. Macromolecular carbon can originate from biological sources, but scientists clarify that it can also be generated through geological processes or even delivered by meteorites. At this juncture, it remains impossible to ascertain whether this carbon stems from ancient Martian microbes.
To address the scientific questions and confirm the origin of these carbon molecules, Martian samples will need to be brought back to Earth. While the rover is capable of identifying promising rocks, it cannot independently confirm if the carbon is biological in origin. NASA is planning a new mission to retrieve samples within the next decade (the 2030s), with China also aiming to collect Martian samples by 2031.