The so-called "serpent storm" that is raging in Saturn's northern hemisphere is so bright and so massive that we here on Earth can easily see it from almost a billion miles away, as this recent photo dramatically reveals.
The serpent storm, so named because it appears to snake its way around what is currently about 100 degrees of longitude across Saturn's northern hemisphere. In Earthly terms, a storm that circled 100 degrees of longitude would extend from New York City all the way to Berlin, and that's not even the greatest extent of the storm - at times, it's closed in on 2/3 the entire length of the northern hemisphere, and on Saturn that's at least 100,000 miles in length.
A NASA astronomer adds:
Late last year, a new, remarkably bright storm erupted in Saturn's northern hemisphere. Nicknamed "the Serpent Storm", the northern hemisphere disturbance is still going strong and now circles far around the planet. Offering spectacular space-based views to the Saturn-orbiting Cassini spacecraft, the storm shows enough contrast with the banded cloud tops to be visible with even modest ground-based equipment, as seen in this sharp image from Buena Vista, Georgia, USA, planet Earth. Amateur astronomers first spotted the bright storm in early December 2010, with the ringed gas giant rising in predawn skies, and continue to monitor the storm's progress.