CICLOPS: Cassini Imaging Central Laboratory for OPerationS

Spokes at Sunrise
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Spokes at Sunrise
PIA 11470

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  Bright spokes emerge from behind the shadow of the planet and into sunlight in this view from cassini.

Saturn's long shadow covers the left side of the image. This view looks toward the sunlit side of the rings from about 22 degrees below the ringplane.

The image was taken in visible light with the Cassini spacecraft wide-angle camera on Feb. 26, 2009. The view was acquired at a distance of approximately 821,000 kilometers (510,000 miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 150 degrees. Image scale is 46 kilometers (28 miles) per pixel.

The Cassini Equinox Mission is a joint United States and European endeavor. 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 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 Equinox Mission visit, and

Credit: NASA/JPL/Space Science Institute
Released: April 14, 2009 (PIA 11470)
Image/Caption Information

Alliance Member Comments
colin (CICLOPS) (Apr 17, 2009 at 10:37 AM):
From their light scattering properties, we know that the spokes are made up of very small particles, about a micron (one millionth of a meter) in diameter. Spokes seem to form when these particles get dispersed above the ring by a process that is not well understood at this time, but is an active area of research.
mipsandbips (Apr 14, 2009 at 9:21 PM):
Interesting question, are the bright spokes reflections
or are they dispersions of the bright ring matter onto the other ring bands?
The matter composition of the outer bright ring must be different then if the spokes are dispersions since there is no visible bright spoke in that outer ring!

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