This image of the lit face of Saturn's outer, or A, ring was taken by the
Cassini spacecraft shortly after crossing the ring plane after its orbit
insertion burn. The image was taken with the narrow angle camera on July
1, 2004. The rings in the middle of the image are approximately 134,000
kilometers (83,200 miles) from the center of Saturn.
The bright wave pattern near the center of the image is caused by the
overlap between spiral waves of varying particle density generated by
Saturn's moons Janus and Epimetheus, which share an orbit. These two moon
orbital periods are very close to each other and, at this location, affect
ring particle orbits.
Cleaner spiral patterns caused by single satellites can be seen in other
images; some of the weaker wave patterns in this image are also spiral
patterns generated by smaller moons outside the main rings. All these
spiral waves are of the same nature as the arms of spiral galaxies. The
finest features which can be discerned (inwards, or to the left, of the
bright wave feature in the center) are less than one mile across. Their
cause is not currently known.
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 Cassini-Huygens mission for NASA's Office of Space
Science, Washington, D.C. The Cassini orbiter and its two onboard cameras,
were designed, developed and assembled at JPL.
For more information, about the Cassini-Huygens mission visit,
http://saturn.jpl.nasa.gov.
