NASA's Perseverance rover finds 4 bn-year-old river delta on Mars

NASA's Perseverance rover detected underground remains of an ancient river delta buried deep beneath the surface of Mars using RIMFAX ground-penetrating radar. It identified layered sediments and eroded surfaces indicative of a delta environment in Jezero Crater area of Mars' northern hemisphere. The findings suggest that the now-buried delta dates back to about 3.7 to 4.2 billion years ago.