http://www.thunderbolts.info/tpod/00current.htmStrange vertical structures in Saturn's B ring. Credit: NASA/JPL/Space Science Institute
Where the Long Shadows Fall
Apr 27, 2011
Wall-like formations in Saturn's rings could be due to electromagnetic effects.
A recent press release argues that Saturn's rings could behave like spiral galaxies. The same forces that create galactic "arms" might be responsible for the unusual features that have been seen rising vertically from the gas giant's ring plane, as well as for the oscillations in the B ring.
According to Carolyn Porco of NASA's Cassini-Equinox mission team: "We have found what we hoped we'd find when we set out on this journey with Cassini nearly 13 years ago: visibility into the mechanisms that have sculpted not only Saturn's rings, but celestial disks of a far grander scale, from solar systems, like our own, all the way to the giant spiral galaxies."
Cassini has been in orbit around Saturn since July 1, 2004. On August 11, 2009 the spacecraft was in position to observe the giant planet's equinox, when its rings turned edge-on to the Sun, something that happens every 15 years. During that phase, several complex configurations were seen within the rings: so-called "propellors," ridges, and waves rising up as high as four kilometers. Since the rings had been long thought to be about twenty meters thick, anomalous meta-stable shapes of such dimension were a complete surprise to mission specialists.
How do clumps, undulations, and ridges form? Researchers suggest collisions and shock waves initiate the resonant vibrations. Gravitational attraction from so-called "shepherd moons" is said to be an additional source of influence. Small moons, such as Daphnis, do move up and down through the ring plane, affecting the motion of ring particles.