Unique 'hexagon' jet-stream phenomenon on Saturn star of new 'movie'

NASA says the Cassini spacecraft has obtained the highest-resolution images yet of a unique six-sided jet stream known as the hexagon at Saturn's north pole. A "movie" of the atmospheric phenomenon from Cassini images using color filters, is the first to show a complete view of the top of Saturn down to about 70 degrees latitude, the space agency reported Thursday. Spanning about 20,000 miles across, the hexagon is a wavy jet stream of 200 mph winds with a massive, rotating storm at the center, and its persistence and consistency make it unlike anything seen elsewhere in the solar system, NASA scientists said. "The hexagon is just a current of air, and weather features out there that share similarities to this are notoriously turbulent and unstable," Andrew Ingersoll, a Cassini imaging team member at the California Institute of Technology in Pasadena, Calif., said. "A hurricane on Earth typically lasts a week, but this has been here for decades -- and who knows -- maybe centuries." Weather patterns on Earth are disrupted when they encounter landforms or ice caps, but scientists say they suspect the stability of the hexagon has something to do with the lack of solid landforms on Saturn, which is essentially a giant ball of gas. Better views of the hexagon are available now because the sun began to illuminate its interior in late 2012, researchers said. "As we approach Saturn's summer solstice in 2017, lighting conditions over its north pole will improve, and we are excited to track the changes that occur both inside and outside the hexagon boundary," said Scott Edgington, Cassini deputy project scientist at NASA's Jet Propulsion Laboratory in Pasadena.