Astronomers are tracking the course of a giant storm from its emergence as a tiny spot in a single image almost one year ago, on Dec. 5, 2010. By late January of this year, it had completely encircled the planet. The storm, which now measures approximately 9,000 miles, is the biggest one to hit Saturn in the last couple of decades. The 200 days of its active period also break a record set in 1903 for the longest-lasting planet-encircling storm on the planet. That storm lasted for 150 days.
In this image, a false-color mosaic from NASA's Cassini spacecraft showing the tail of Saturn's huge northern storm.
Credit: NASA/JPL-Caltech/Space Science Institute
The following slides show the development of the largest storm as tracked by the Cassini spacecraft.
"This new storm is a completely different kind of beast compared to anything we saw on Saturn previously with Cassini," said Kunio Sayanagi, a Cassini imaging team associate and planetary scientist at the University of California, Los Angeles. "The fact that such outbursts are episodic and keep happening on Saturn every 20 to 30 years or so is telling us something about deep inside the planet, but we have yet to figure out what it is."