When the Perseverance rover landed in Mars’s Jezero crater—a formation that long ago was Jezero lake—in February, 2021 it turned west. West is where the riverbeds, the deltas, the sites of ancient gushing water once were. In July, 2024, after covering 18 miles in nearly three and a half years, it arrived at a quarter-mile-wide river valley that is home to a 3.2-ft.-long rock NASA scientists have dubbed Cheyava Falls—and there it hit paydirt. As a new paper in Nature reports, a sample