NASA's Cassini spacecraft has captured detailed images of the intricate workings of Saturn's F ring. It appears to be more dynamic than was previously thought.
New images from the Cassini spacecraft have revealed kilometer-sized objects piercing through parts of Saturn’s F ring, leaving glittering trails behind them. These trails in the rings, which scientists are calling “mini-jets,” provide insight into the curious behavior of the F ring, which Cassini imaging team leader Carolyn Porco called “Saturn’s most beguiling phenomena.” With new detailed images, Cassini reveals the intricate workings of the F ring and hordes of tiny moonlet companions creating the trails.
“I think the F ring is Saturn’s weirdest ring, and these latest Cassini results go to show how the F ring is even more dynamic than we ever thought,” said Carl Murray, a Cassini imaging team member from Queen Mary University of London, England. “These findings show us that the F ring region is like a bustling zoo of objects from a half mile [kilometer] in size to moons like Prometheus a hundred miles [kilometers] in size, creating a spectacular show.”
Scientists have known that relatively large objects like Prometheus (as long as 92 miles, or 148 kilometers, across) can create channels, ripples and snowballs in the F ring. But scientists didn’t know what happened to these snowballs after they were created, Murray said. Some were surely broken up by collisions or tidal forces in their orbit around Saturn, but now scientists have evidence that some of the smaller ones survive, and their differing orbits mean they go on to strike through the F ring on their own.
These small objects appear to collide with the F ring at gentle speeds – something on the order of about 4 mph (2 meters per second). The collisions drag glittering ice particles out of the F ring with them, leaving a trail typically 20 to 110 miles (40 to 180 kilometers) long. Murray’s group happened to see a tiny trail in an image from Jan. 30, 2009 and tracked it over eight hours. The long footage confirmed the small object originated in the F ring, so they went back through the Cassini image catalog to see if the phenomenon was frequent.