The international Cassini spacecraft has spotted what appears to be an ice volcano on Saturn's planet-size moon, a finding that may help explain the source of Titan's thick atmosphere. Infrared images snapped by the orbiting Cassini reveal a 20-mile (32-kilometer) -wide dome that appears to be a cryovolcano, a volcanic-like vent that spews forth ice instead of lava. Scientists theorize the volcano at one time spat out icy plumes that released methane into Titan's atmosphere. The findings appear in Thursday's issue of the journal Nature, The Associated Press reported. Titan is the only moon in the solar system that has a significant atmosphere made up of nitrogen and methane. Its atmosphere is similar to that of primordial Earth and scientists believe that studying it could provide clues to how life began.
