Many people have been astounded by the beauty of the aurora borealis and aurora australis light displays which occur over the North and South Poles of Earth. These light shows are one of the natural wonders of our world and anyone who views them is certain to be impressed. However fewer people will be aware that auroras also occur on other planets in our universe. The latest one to be identified towers high over Saturn and was discovered by the Cassini spacecraft.
The Cassini project was set up and executed by three agencies these being the National Aeronautics and Space Administration (NASA), the European Space Agency and the Italian Space Agency. The spacecraft was launched in 1997 with its mission being to explore the planet Saturn and its system. The spacecraft took 7 years to reach Saturn and once there its initial mission to explore the planet took a further 4 years to complete. However this raised many further questions about Saturn and with the spacecraft remaining healthy it is now into overtime in its mission. It is currently being used to try and answer some of the questions raised during its 4 year mission
The spacecraft made a pass over the northern polar region of Saturn in October 2009 and infrared instruments detected a stunning light display. The aurora is the largest identified in our solar system to date and towers a massive 1,200 kilometers above the northern hemisphere of the planet. Although scientists have long suspected the aurora was present, the images sent back by Cassini in November are the first time they have actually been viewed in high resolution and provided conclusive evidence of their existence.
Auroras generally form in the high latitudes around a planet’s magnet poles. They are known to occur on Earth, Saturn and Jupiter and are caused by charged particles plunging into a planet’s atmosphere along magnetic lines. This causes the atmosphere to glow and produces the stunning light shows typical of the aurora borealis on Earth.
The video images of the huge aurora above Saturn should help scientists better understand the processes involved in generating them. The moving images was put together from around 500 still pictures which were taken over an 81 hour period between the 5th and 8th of October 2009. The finished video showed that there are very rapid changes in the shape and brightness of the aurora as it gyrates above the planet. The height of the aurora should also provide some clues into the amount of energy that is required to light it up.
The Cassini mission is currently scheduled to continue until September 2010 and it will continue to send back data regarding Saturn and its surrounding system until this time. With 2009 drawing to a close the highlights of the year for the project have included multiple flybys of Titan and Enceladus. These are two of Saturn’s many moons and further flybys of these are planned for the remainder of the mission. Data ring scientists also paid close attention in August when Saturn went through the Solar Equinox with the sun crossing from the southern to the northern hemisphere and this provided excellent conditions to view the rings.
In the 12 years since its launch the Cassini spacecraft has proved to be a stunning success and the data and images it has sent back about the planet Saturn and its moons has greatly increased our understanding of the system. Hopefully further discoveries will be made in the coming weeks and months until the completion of the mission and that these will help scientists in their quest to understand our solar system.