When seen up close, Saturn’s F ring — the outermost discrete ring of the gas giant — resolves into multiple dusty strands.
This Cassini view shows four dusty strands of Saturn’s F ring: the central strand is the core of the ring; the other strands are not independent at all, but are actually sections of long spirals of material that wrap around the gas giant; the material in the spirals was likely knocked out from the F ring’s core during interactions with a small moon. Image credit: NASA / JPL-Caltech / SSI.
Saturn’s F ring, a narrow ring of icy particles, is between 18 and 310 miles (30-500 km) wide.
With an orbital radius of 87,600 miles (141,000 km), the ring lies about 2,100 miles (3,400 km) beyond the outer edge of the gas giant’s main ring system.
Enigmatically, the F ring is accompanied on either side by two small satellites, Prometheus and Pandora, which are called shepherd moons.
According to a recent study, the system of the F ring, Prometheus, and Pandora is a natural outcome of the final stage of formation of Saturn’s satellite system.
The F ring is composed of millions of small (about 0.4 inches, or 1 cm) particles traveling around Saturn at speeds of 38,000 mph (17 km/s).
The ring was discovered in 1979 by NASA’s Pioneer 11 spacecraft.
Although the Pioneer 11 images suggested something unusual, it was the Voyager 1 pictures in 1980 that showed a ring composed of at least four separate, non-intersecting strands.
The new image from NASA’s Cassini orbiter shows three bright strands and a very faint fourth strand off to the right.
The image was taken in visible light with Cassini’s narrow-angle camera on December 18, 2016.
The view was acquired at a distance of about 122,000 miles (197,000 km) from Saturn and looks toward the unilluminated side of the planet’s rings from about 38 degrees above the ring plane.
