Cosmic quiver: Saturn's vibrations create spirals in rings

Astronomers know that gravity from Saturn's various moons tug at the planet's rings and make spirals in them. But the catalyst for certain spiral patterns has been difficult to pin down. Now, two Cornell astronomers have determined the source: Saturn itself. The entire planet can vibrate like a bell within periods of a few hours, and these oscillations cause gravitational tugs that, in turn, create the spiral patterns in the rings. The cause of the vibrations remains unknown. "The locations and properties of these ring disturbances tell us how and with what periods the planet oscillates," said senior research associate Matthew Hedman, whose new research was published June 11 in The Astronomical Journal. He also presented the research May 9 at the meeting of the American Astronomical Society's Division for Dynamical Astronomy in Paraty, Brazil.