NASA says it's found new evidence that water may have once flowed on the Red Planet. Scientists studying samples of rock analyzed by the Mars rover Opportunity say they see chemical signs of contact with water. NPR's Joe Palca reports.
Copyright 2022 NPR. To see more, visit https://www.npr.org. 9(MDAzMjM2NDYzMDEyMzc1Njk5NjAxNzY3OQ001))
