Life on Mars: What we know after NASA's announcement

NASA’s sample return mission faces funding and schedule hurdles, leaving the timing of further analysis uncertain. "This is the closest we’ve actually come to discovering ancient life on Mars," NASA science mission chief Nicky Fox said. NASA scientists say ancient river valleys and mineral deposits point to a wetter past that may have supported life. Why the Mars rock sample could point to past microbesBig picture view:If confirmed, the discovery would represent the first evidence of life beyond Earth. The findings also raise the stakes for NASA’s Mars Sample Return mission.