Enigmatic Moon

To the eye, Saturn's giant moon Titan is rather boring -- an uninterrupted blanket of orange topped by a thin blue haze, as seen in this view from the Cassini spacecraft. Yet that blanket of orange helps make Titan one of the most intriguing objects in the solar system. The orange is a layer of smog produced by hydrocarbons, much like the smog on Earth. It conceals a surface that is molded by the motions of hydrocarbon rivers, dotted by hydrocarbon lakes, and partially covered by hydrocarbon dunes. The combination of chemistry and energy sources provide the key ingredients for life on Titan's frigid surface. [NASA/JPL/SSI]