Billions of years after water last flowed through Jezero Crater, NASA's Perseverance rover has found macromolecular carbon preserved just beneath the Martian surface — a discovery that extends the known geography of organic material across more than 2,000 miles of the ancient planet. The finding does not confirm that life once existed on Mars, but it suggests that the chemical preconditions for life were not isolated accidents; they may have been woven into the fabric of a world that was once, in some meaningful sense, hospitable. What the rover has uncovered is not an answer, but a more urgen