"Clumps" in the A-Ring

Original NASA caption:"The left image is a false-color view of Saturn's A-Ring from the Ultraviolet Imaging Spectrograph aboard Cassini.
The A-Ring is the bluest in the center, where the gravitational clumps are the largest. The thickest black band in the Ring is the "Encke-Gap" while the thin black band further to the right is the "Keeler-Gap".
The right image is a computer simulation about 150 mt (about 490 feet) across illustrating a "clumpy region" of particles in the A-Ring. And, there and that is the 'real surprise'...The particles are moving counterclockwise, from bottom to top!".