This graphic illustrates how scientists on NASA's Cassini mission think water interacts with rock at the bottom of the ocean of Saturn's icy moon Enceladus, producing hydrogen gas. NASA's Cassini spacecraft detected the presence of molecular hydrogen in water plumes erupting from Saturn's icy moon Enceladus, the U.S. space agency announced Thursday, suggesting that the distant world has almost all the conditions necessary for life. (Photo/Agencies)
