Click on image for larger annotated version
This false-color image of Saturn's main rings was made by combining data
from multiple star occultations using the Cassini ultraviolet imaging
spectrograph.
During occultations, scientists observe the brightness of a star as the
rings pass in front of the star. This provides a measurement of the amount
of ring material between the spacecraft and the star.
Cassini has given scientists the most detailed view yet of Saturn's
densely packed B ring. Cassini found that this part of the rings is
densely packed with clumps, called self-gravity wakes, separated by nearly
empty gaps. These clumps in Saturn's B ring are neatly organized and
constantly colliding, which surprised scientists.
The clumps in Saturn's B ring, 30 to 50 meters (100 to 160 feet) across,
are too small to be seen directly. However, scientists can map the
distribution, shape and orientation of the clumps. Colors in this image
indicate the orientation of clumps, and brightness indicates the density
of ring particles. The formation of wakes is strongest in the bluer
regions, where ring particles clump together in tilted wakes. Particles in
the central yellow regions are too densely packed for any starlight to
pass through.
The ultraviolet imaging spectrograph measured the flickering of the star
Alpha Arae as it passed by the rings Nov. 9 and 10, 2006.
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 was designed, developed and assembled
at JPL. The ultraviolet imaging spectrograph was designed and built at,
and the team is based at the University of Colorado, Boulder.
For more information about the Cassini-Huygens mission visit
http://saturn.jpl.nasa.gov/home/index.cfm. The ultraviolet imaging
spectrograph team home page is at http://lasp.colorado.edu/cassini.
