Cassini Image of Saturn’s Rings and Its Moon Prometheus

Saturn’s Rings and its neighboring moon Prometheus. Credit: NASA/JPL-Caltech/Space Science Institute

NASA’s Cassini Spacecraft views Saturn’s Rings and its neighboring moon Prometheus.

Most planetary rings appear to be shaped, at least in part, by moons orbiting their planets, but nowhere is that more evident than in Saturn’s F ring. Filled with kinks, jets, strands, and gores, the F ring has been sculpted by its two neighboring moons Prometheus (seen here) and Pandora. Even more amazing is the fact that the moons remain hard at work reshaping the ring even today.

Prometheus (53 miles, or 86 kilometers across) shapes the F ring through consistent, repeated gravitational nudges and occasionally enters the ring itself (clearing out material and creating a “gore” feature). Although the gravitational force of Prometheus is much smaller than that of Saturn, even small nudges can tweak the ring particles’ orbits to create new patterns in the ring.

This view looks toward the sunlit side of the rings from about 12 degrees above the ring plane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on February 21, 2016.

The view was obtained at a distance of approximately 1.4 million miles (2.3 million kilometers) from Saturn and at a Sun-Saturn-spacecraft or phase angle of 105 degrees. The image scale is 9 miles (14 kilometers) per pixel.