Perseverance has discovered an ancient river delta beneath the surface of Mars! The rover's radar penetrated more than 35 meters and discovered unexpected subsurface structures. Beneath a layer of rock and dust lies a buried ancient river delta—and it's older than the delta Perseverance was sent to Jezero Crater to see. What does this mean? Water existed in Jezero Crater significantly earlier than the visible delta indicated. This means the window during which life could have originated on Mars, or at least preserved traces of it, is wider than previously thought.