Top Stories Photos - AP

This image provided by NASA Wednesday Dec. 9, 2009 shows the hexagon jet stream flowing around Saturn's north pole captured by the Cassini spacecraft. The last visible-light images of the entire hexagon were captured by NASA's Voyager spacecraft nearly 30 years ago, the last time spring began on Saturn. According to scientists 'It's a mystery on par with the strange weather conditions that give rise to the long-lived Great Red Spot of Jupiter.' he hexagon was originally discovered in images taken by the Voyager spacecraft in the early 1980s. It encircles Saturn at about 77 degrees north latitude and has been estimated to have a diameter wider than two Earths. The jet stream is believed to whip along the hexagon at around 100 meters per second (220 miles per hour).