Gas giants are turbulent places. While Jupiter is famous for its great red spot, a storm which is so large that we can see it from here on Earth, Saturn too is quite a stormy world. And every now and again, it likes to remind us of that.
Between December 2010 and February 2011, Saturn was home to a storm so large that its head was the size of planet Earth, and its tail was so long that it wrapped around the whole planet. Think about that for a minute.
But even more impressively, the Cassini probe happened to be looking at Saturn through a blue filter and caught a glimpse of this.
That, brief enough to only be seen in Cassini’s blue filter, is a lightning flash. A huge, gas giant lightning strike.
Saturn is already a windy world, with wind speeds reaching over 500 metres per second – some of the fastest winds in the solar system. Swept around by that wind are clouds full of interesting chemicals. Small hydrocarbons like propane and acetylene, intermingled with more unusual things like phosphine. These are amid Saturn’s weatherbeaten clouds, made up of ice crystals formed from frozen ammonia and ammonium hydrosulfide.
Those high altitude clouds made up of frozen ammonia are where the ligtning originated – not unlike the way lightning on Earth comes from parts of the atmosphere cold enough to freeze water into ice crystals. The result in this case, however, was a lightning strike which would have been large enough to illuminate a small country. Staggering.
With a tip of the hat to His Badness, Phil Plait!
Image credits:NASA/JPL-Caltech/Space Science Institute