Jupiter has its Great Red Spot – Saturn, in contrast, has its enormous hexagon. For a long time, a six-sided structure with a diameter of 29,000 km (18,000 miles) has been rotating around Saturn’s north pole. Thus, the hexagon is considerably larger than Jupiter’s spot, which is only 16,000 km (10,000 miles) across and more than twice as large as the whole Earth. The hexagon was first discovered in 1981 by Voyager 1 (photographed in infrared in the image below).
Starting in 2006, the Cassini probe, operated by NASA and ESA, made it possible to take a detailed look at the structure of the hexagon, which needs about ten hours and 39 minutes for one rotation. It appears to be clear that the hexagon is formed by jet streams moving at speeds greater than 300 km/h (186 mph). But how the unusual shape is created has not yet been completely explained. One cause might be that the wind speeds vary greatly depending on latitude. In laboratory simulations in a round water tank, regular polygons also formed when the liquid in the center rotated faster than at the edge.