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 NASAs Cassini spacecraft showing the tail of Saturns huge northern storm. CBS