http://www.space.com...-explained.html
The huge, mysterious hexagon at Saturn's north pole may finally have an explanation.
The bizarre hexagonal cloud pattern was first discovered in 1988 by scientists reviewing data from NASA's Voyager flybys of Saturn in 1980 and 1981, but its existence was not confirmed until NASA's Cassini spacecraft observed the ringed planet up-close years later.
Nothing like the hexagon has ever been seen on any other world. The structure, which contains a churning storm at its center, is about 20,000 miles (32,000 kilometers) wide, and thermal images show that it reaches roughly 60 miles (100 km) down into Saturn's atmosphere.