Enceladus

Guest: Carolyn Porco, PhD, Leader of the Imaging Team on the Cassini Mission to Saturn  Saturn is already among the most popular planets for amateur sky watchers, because you can make out its rings even with a pair of binoculars. For a decade now, the unmanned spacecraft Cassini has been sending back much closer shots of Saturn and its 60-plus moons as it orbits Saturn. NASA scientists are particularly intrigued by a moon called Enceladus that has giant icy geysers bursting from its southern pole. The images are really cool—check them out at ciclops.org, where all of the Cassini images are posted.   The big new discovery by the Cassini Mission to Saturn is that those geysers are just the tip of the iceberg, so to speak. Researchers now believe the entire moon is covered liquid—a global ocean.