Gravity-induced "Ondulations"

Caption NASA:"Saturn's moon Daphnis gives a scalloped look to the edge of the A-Ring as the moon orbits within the Keeler Gap.
Daphnis is the bright spot in the narrow gap near the center of the image. Since the gap is not much larger than the moon, the small moon's gravity is great enough to perturb the particles in the Ring and create the wavelike patterns seen here. See also PIA09850 to learn more.

This view looks toward the unilluminated side of the Rings from about 61° above the Ring-Plane. The image was taken in Visible Light with the Cassini Spacecraft narrow-angle camera on April 30, 2009. The view was acquired at a distance of approx. 1,5 MKM (such as about 932.000 miles) from Daphnis and at a Sun-Daphnis-Spacecraft, or Phase, angle of 73°.
Image scale is roughly 9 Km (a little less than 6 miles) per pixel".