Different Light, Different Brightness, Different Motion...

Caption NASA:"This close-up view of the inner A-Ring shows intriguing variations in brightness along the direction of the Ring motion - from top to bottom. Close examination reveals dark regions that appear to widen and then narrow, and thin bright regions that disappear altogether.

Variations in brightness are to be expected in the direction of increasing orbital distance from Saturn, but variations along the azimuthal (or circumferential) direction are unusual, as they should be smoothed out quickly by ring particle motion.

Note: the faint "doughnut" left of center and the dark area in the lower right corner are imaging artifacts.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on July 23, 2006 at a distance of approx. 285.000 Km (about 177.000 miles) from Saturn. Image scale is about 1 Km (0,6 mile) per pixel".