Titan's Icy Shell is Stronger Than Expected

Saturn's largest moon, Titan, is one of the solar system's most fascinating destinations. It's the second biggest moon in the solar system and the only one known to possess a thick atmosphere. The Cassini-Huygens mission has found it to be weirdly Earth-like, with rocky plains, languid lakes and even precipitation -- only the world is so cold the rocks are probably water ice, and the lakes liquid methane. Now even its interior is giving up secrets, thanks to the gravitational data Cassini's b