Saturn has been known to erupt in storms from time to time. Though not as active as Jupiter, the weather in Saturn's atmosphere has been known to form large swirling vortexes. Now, in one of the largest storms ever observed on the planet, astronomers have spotted signs of water ice.
The storm in question occurred on Saturn in 2010, and is the same one researchers determined was so large that it wrapped around the planet and ran into itself. New research on the storm shows that the storm was so large that it brought water ice from deep in the planet's atmosphere to the surface. The observations were made by NASA's Cassini probe, which observed the storm with infrared instruments. They have been published this week in the journal Icarus.
"We think this huge thunderstorm is driving these cloud particles upward, sort of like a volcano bringing up material from the depths and making it visible from outside the atmosphere," said Lawrence Sromovsky, lead author of the paper and a planetary scientist at the University of Wisconsin-Madison. "The upper haze is so optically thick that it is only in the stormy regions where the haze is penetrated by powerful updrafts that you can see evidence for the ammonia ice and the water ice. Those storm particles have an infrared color signature that is very different from the haze particles in the surrounding atmosphere."
Sromovsky and his colleagues found signatures for water and ammonia ice among the Cassini data, as well as a third unconfirmed substance they believe to be ammonium hydrosulfide. This supports current theories about Saturn's atmosphere, which scientists believe to be composed of distinct layers. Water clouds are believed to reside at a layer more than 100 miles deep within Saturn. The observed ice could have come from this layer, frozen as it was churned upward by the storm.
(Image courtesy NASA/JPL-Caltech/Space Science Institute)