Dark straw-like patterns dot the bright outer B ring just left of the Huygens Gap in the center of this image from the Cassini spacecraft.
Cassini scientists speculate that these features are likely the result of transient gravitational clumping.
The outer edge of the B ring is anchored and sculpted by a powerful gravitational resonance with the moon Mimas (396 kilometers, or 246 miles across). The mutual gravity between particles may pull them into clumps as they are periodically forced closely together by the action of Mimas. (see Inspecting the Edge for a closer view).
The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Dec. 8, 2008. This view looks toward the unilluminated side of the rings from about 61 degrees above the ringplane. Cassini captured this view at a distance of approximately 710,000 kilometers (440,000 miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 65 degrees. Image scale is 4 kilometers (2 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.
Credit: NASA/JPL/Space Science Institute