Attraction-Repulsion: the strange relationship between Prometheus and the F-Ring

Caption NASA originale:"Intriguing features resembling drapes and kinks are visible in this Cassini view of Saturn's thin F-Ring. Several distinct ringlets are present, in addition to the bright, knotted core of the ring.
The obvious structure in the ring and its strands has been caused by Prometheus, the inner F-Ring shepherd moon that recently swept past this region. (Prometheus is about 10° ahead of the F-Ring material in this image). These types of features were first seen in images taken just after Cassini entered into orbit around Saturn. The gravitational interaction of Prometheus (102 Km or 63 miles across) on the ring pulls material out the ring once every orbit (every 14,7 hours) as the moon gets close to the ring and its strands".