This high-resolution view shows incredible detail within a spiral density
wave within Saturn's A ring.
A spiral density wave is a spiral-shaped massing of particles that tightly
winds many times around the planet. These waves decrease in wavelength
with increasing distance from the planet.
The wave that covers a broad strip across the center of the image is
created by a gravitational resonance with the moon Janus. For every sixth
orbit of the ring particles at this radius from Saturn, Janus makes five
orbits, meaning that the moon is continually providing a gravitational
kick to particles in this region of the rings.
A couple of the peaks in the broad Janus-created wave appear bunched
together, possibly owing to Janus' orbit being changed when it swaps
places with its co-orbital moon Epimetheus (see PIA08170).
This view looks toward the sunlit side of the rings from about 34 degrees
below the ringplane.
The image was taken in visible light with the Cassini spacecraft
narrow-angle camera on July 21, 2008. The view was acquired at a distance
of approximately 170,000 kilometers (106,000 miles) from Saturn. Image
scale is 669 meters (2,194 feet) 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.