CICLOPS: Cassini Imaging Central Laboratory for OPerationS
Bent Spoke

A bright spoke extends across the unilluminated side of Saturn's B ring about the same distance as that from London to Cairo. The background ring material displays some azimuthal (i.e., left to right) asymmetry.

The radial (outward from Saturn) direction is up in this view. A noticeable kink in the spoke occurs very close to the radius where ring particles orbit the planet at the speed of Saturn's magnetic field. Such a connection is most intriguing to scientists studying these ghostly ring phenomena.

If gravity alone were affecting the spoke material, there would be no kink and the entire spoke would be angled toward right, like the bottom portion. That it bends to the left above the kink indicates that some other force, possibly related to the magnetic field, is acting on the spoke material. The shape might also indicate that the spoke did not form in a radial orientation, thus challenging scientists' assumptions about these features.

This view looks toward the unlit side of the rings from about 58 degrees above the ringplane.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Jan. 23, 2007 at a distance of approximately 1.6 million kilometers (1 million miles) from Saturn. Image scale is 10 kilometers (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 Cassini-Huygens mission for NASA's Science Mission Directorate, Washington, D.C. The imaging team consists of scientists from the US, England, France, and Germany. The imaging operations center and team lead (Dr. C. Porco) are based at the Space Science Institute in Boulder, Colo.

For more information about the Cassini-Huygens mission, visit and the Cassini imaging team home page,

Credit: NASA/JPL/Space Science Institute
Released: March 7, 2007 (PIA 08891)
Image/Caption Information
  Bent Spoke
PIA 08891

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Alliance Member Comments
djbarney (Mar 7, 2007 at 7:49 PM):
I can never get the title sequences of ST:Voyager out of my mind when viewing these kind of images. I wonder how easy these rings would actually be to navigate ? With navigation hazards and the mag field. An astronomy student told me that Cassini sometimes has to cope with a charge building up from the planet...but it was'nt very much.....I forget the exact figure.

Ed Rolko (Mar 7, 2007 at 2:04 PM):
I often wonder if the alternating heating and cooling of the ring particles as they transition the sunlight and shade causes a type of "rogue wave" effect in the rings. Or, if Saturns magnetic field is slightly "off axis", I'm thinking along the line of like Earth having "north" and "magnetic north", and also I wish I knew if the magnetic field ever "flips". Could any of these be possible contributing factors to the formation of spokes? I sure do wish I knew!!!