Analysis by instruments aboard NASA’s Perseverance Mars rover indicate that the latest rock core taken by the rover was awash in water for an extended period of time in the distant past, perhaps as part of an ancient Martian beach. Collected on March 11, the sample is the rover’s 24th – a tally that includes 21 sample tubes filled with rock cores, two filled with regolith (broken rock and dust), and one with Martian atmosphere. “To put it simply, this is the kind of rock we had hoped ...