Scientists working with images from NASA's Cassini spacecraft have discovered strange, half-mile-sized objects punching through one of Saturn's rings and leaving glittering trails behind them. The penetration occurred in the outermost of Saturn's main rings, called the F ring, which has a circumference of 550,000 miles (881,000 kilometers). Scientists are calling the trails in the F ring "mini-jets." Cassini scientists combed through 20,000 images and found 500 examples of these rogues during the seven years Cassini has been at Saturn.
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| This set of six images obtained by NASA's Cassini spacecraft shows trails that were dragged out from Saturn's F ring by objects about a half mile (1 kilometer) in diameter. NASA/JPL-Caltech/SSI/QMUL |
"Beyond just showing us the strange beauty of the F ring, Cassini's studies of this ring help us understand the activity that occurs when solar systems evolve out of dusty disks that are similar to, but obviously much grander than, the disk we see around Saturn," said Linda Spilker, Cassini project scientist at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif.
Although scientists have known that in the F ring, large objects can make the channels, ripples, and snowballs. However, so far scientists do not know what happened after the snowball is created. Some were broken up by collisions or tidal forces in their orbit around Saturn. Scientists now have evidence some of the smaller ones survived, and their differing orbits mean they go on to strike through the F ring on their own.
"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 based at Queen Mary University of London, U.K. "These findings show us that the F ring region is like a bustling zoo of objects from a half-mile (0.8-kilometer) in size to moons like Prometheus a hundred miles (160.9 kilometers) in size, creating a spectacular show."
These small objects appear to collide with the F ring at gentle speeds about 4 mph (2 meters per second). The collisions drag glittering ice particles out of the F ring with them, leaving a trail of 20-110 miles (40-180 kilometers) long.
In some cases, the objects traveled in packs, creating mini-jets that looked exotic, like the barb of a harpoon. Other new images show grand views of the entire F ring and the swirls and eddies from the different kinds of objects moving through and around it.
Saturn's rings are comprised primarily of water ice. The chunks of ice that make up the main rings spread out 85,000 miles (140,000 kilometers) from the center of Saturn. Scientists believe the rings' average thickness is approximately 30 feet (10 meters).
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