Spiral density waves in Saturn's A ring reveal the gravitational
signatures of distant moons as they subtly tug on the countless particles
orbiting in the ring plane.
Resulting from a process called orbital resonance, a spiral density wave
is a spiral-shaped massing of particles that tightly winds many times
around the planet. Thus, the wave patterns seen here represent successive
windings of each wave, like a close-up view of a watch spring.
Ring scientists can read these patterns, learning from them how quickly
the rings are spreading and the amount of mass contained in a region.
This view looks toward the sunlit side of the rings from about 42 degrees
below the ringplane. The image was taken in visible light with the Cassini
spacecraft narrow-angle camera on April 1, 2008. The view was obtained at
a distance of approximately 268,000 kilometers (167,000 miles) from
Saturn. Image scale is 1 kilometer (0.6 miles) per pixel.
The Cassini-Huygens mission is a cooperative project of NASA, the European
Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory,
a division of the California Institute of Technology in Pasadena, manages
the mission for NASA's Science Mission Directorate, Washington, D.C. The
Cassini orbiter and its two onboard cameras were designed, developed and
assembled at JPL. The imaging operations center is based at the Space
Science Institute in Boulder, Colo.
For more information about the Cassini-Huygens mission visit
http://saturn.jpl.nasa.gov/. The Cassini imaging team
homepage is at http://ciclops.org.