11. Saturn

11. Saturn

Courtesy of NASA/JPL/Space Science Institute

http://photojournal.jpl.nasa.gov/catalog/PIA09749


As a gas giant, Saturn is mostly atmosphere. The atmosphere is mostly hydrogen and helium but also contains trace elements that ammonia, phosphine, methane, and other compounds.
Saturn has powerful lightning storms, 10,000 times stronger than on Earth, that occur in huge, deep thunderstorms columns nearly as large as the entire Earth. The storms occasionally burst through to the planet's visible cloud tops.
In this image taken by the Cassini spacecraft, large swirling storms edge their way along the boundary between east/west flowing cloud bands.