Striking new photos of water-vapor geysers erupting from Saturn's moon Enceladus were beamed to Earth this week by NASA's Cassini spacecraft in orbit around the ringed planet.
Cassini made its deepest dive yet into the plumes pouring out from the moon's south pole on Nov. 2 during a planned flyby of Enceladus. The spacecraft approached within about 62 miles (100 km) of the moon's surface.
The powerful plumes, which contain water vapor, sodium and organic chemicals such as carbon dioxide, look a bit like the Old Faithful geyser in Yellowstone National Park. They have intrigued scientists because they suggest that a store of liquid water may be present beneath the moon's crust to give rise to the water vapor in the plumes. And if there is liquid water, there might be the possibility of some kind of alien life.
"If we can put the pieces together — a liquid ocean under the surface, heat driving the geysers and the organic molecules that are the building blocks of life - Enceladus might turn out to have the conditions that led to the origin of life on an earlier version of Earth," Cassini scientist Bonnie J. Buratti wrote on NASA's Jet Propulsion Laboratory blog.
The aim of the recent flyby - Cassini's seventh targeted swoop toward Enceladus - was to measure the size, mass, charge, speed and composition of the particles within the plume. The spacecraft made a quick approach traveling at about 18,000 mph (nearly 29,000 kph). In addition to the scientific data, the spacecraft returned new stunning snapshots showing the enigmatic geysers glowing in reflected sunlight against the dark backdrop of space.
"Not too bad being in orbit around Saturn, is it ?! ;-)" wrote Carolyn Porco, head of Cassini's imaging science team, via Twitter. Porco called the images "spectacular."
The joint U.S.-European Cassini spacecraft was launched in 1997 on a mission to orbit Saturn, and discovered the geysers on Enceladus in 2005. The spacecraft completed its primary mission in 2008 and is currently in the middle of an extended phase that runs through 2010.
"This is the first time we've found activity on a moon this small," Buratti wrote, explaining that Enceladus is only about the width of Arizona, with a diameter of 310 miles (500 km).