Saturn's mostly smooth surface belies its stormy nature. The pale yellow atmosphere is home to unstoppable lightning storms.
Record-Setting Lightning Storm
A lightning storm on Saturn that was first observed in mid-January 2009 was still going strong in September of the same year. It holds the record for the solar system's longest continuously observed thunderstorm, with the former record also belonging to Saturn. The previous record-holding storm occurred between November 2007 and July 2008.
The Cassini spacecraft has been orbiting Saturn since July 2004. It has analyzed nine thunderstorms in that time. The Cassini spacecraft measures powerful radio waves that are produced by the lightning. These radio waves that come from Saturnian storms are 10,000 times stronger than their earthly counterparts. The findings corroborate early Voyager findings that indicated the levels of ionization are 100 times higher on the day side of Saturn's ionosphere than on its night side.
Dr. Georg Fischer of the Austrian Academy of Sciences elaborates. "These lightning storms are not only astonishing for their power and longevity, the radio waves that they emit are also useful for studying Saturn's ionosphere, the charged layer that surrounds the planet a few thousand kilometers above the cloud tops. The radio waves have to cross the ionosphere to get to Cassini and thereby act as a natural tool to probe the structure of the layer and the levels of ionization in different regions."
Locations of Storms on Saturn
Just as the United States has a "tornado alley" where tornadic storms are most likely to appear, there is a similar stormy region on the planet Saturn. Most of the lightning storms occur in "Storm Alley," a region 35 degrees south of Saturn's equator.
Dr. Fischer explains: "The reason why we see lightning in this peculiar location is not completely clear. It could be that this latitude is one of the few places in Saturn's atmosphere that allow large-scale vertical convection of water clouds, which is necessary for thunderstorms to develop. However, it may be a seasonal effect. Voyager observed lightning storms near the equator, so now that Saturn has passed its equinox on the eleventh of August, we may see the storms move back to equatorial latitudes."
Other Weather on Saturn
Some of the other unique Saturn weather discoveries made by Cassini include a hurricane-like storm and a hexagonal storm. The hurricane-like storm was the size of Earth and seen raging at 350 miles per hour over the South Pole. The hexagon-shaped storm was first seen by both Voyager spacecraft before being targeted by Cassini. This storm is as large as four Earths.
Despite the bland appearance of Saturn's atmosphere, unique storms are always popping up.
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