Space scientists have been watching the longest continuously observed thunderstorm in the solar system raging on planet Saturn.

The powerful storm, complete with lightning 10,000 times more powerful than on Earth, began in mid-January 2009 and is still going strong eight months later.

Such storms are clearly regular events. The new record breaks a previous one set by a storm which lasted from November 2007 to July 2008, lasting 7.5 months. Amateur astronomers helped monitor that storm through their backyard telescopes.

Both were spotted and monitored by NASA’s Cassini spacecraft in orbit around the giant ringed world. Who knows how long storms have lasted in the years before Cassini’s arrival at Saturn in 2004.

The current thunderstorm on Saturn is the ninth to be observed since then. Scientists are able to listen in to very powerful radio waves emitted by the lightning flashes using the antennas and receivers of the Cassini Radio and Plasma Wave Science instrument.

The radio waves are about 10,000 times stronger than their terrestrial counterparts and originate from huge thunderstorms in Saturn’s atmosphere with diameters around 3,000 km, Dr Georg Fischer of the Austrian Academy of Sciences will tell the European Planetary Science Congress today in Potsdam, Germany.

Dr Fischer said: “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 kilometres above the cloud tops.”

The observations of Saturn lightning using the Cassini RPWS instrument are being carried out by an international team of scientists from Austria, the US and France. Results have confirmed previous studies of the Voyager spacecraft indicating that levels of ionisation are approximately 100 times higher on the day-side than the night side of Saturn’s ionosphere.

As we reported last month, torrential rain has also been spotted on Saturn’s amazing moon Titan.

Picture: Saturn’s moon Tethys sits quietly above the planet as a train of earlier storms rumbles through the its southern hemisphere in July 2008. (Credit: NASA).

• Discover space for yourself and do fun science with a telescope. Here is Skymania’s advice on how to choose a telescope. We also have a guide to the different types of telescope available.