DescriptionSaturn ring spokes PIA11144 300px secs15.5to23 20080926.ogv
Dark spokes dance around Saturn's B ring in this series of movies comprised of images taken with Cassini's wide-angle camera.
This animation is from the sequence taken on 26 September 2008: 15.5 to 23 seconds extracted from a concatenation of spoke movies acquired by NASA's Cassini spacecraft.
As Saturn nears equinox in August 2009 and the sun angle on the ring plane decreases, spokes become common sights in Cassini images, just as they were in Voyager images. The planet's orbital period is 29.5 years, so Saturn has nearly made one complete trip around the sun since the flybys of the two Voyager spacecraft in 1980 and 1981, allowing Cassini to closely match Voyager's viewing geometry.
This movie shows the sunlit side of the rings at low solar phase, or spacecraft-rings-sun, angles. The spokes appear dark against Saturn's B ring at low phase angles because the particles within them scatter light more efficiently in the forward direction (away from Cassini) than the surrounding larger ring particles. In the opposite viewing geometry, at high phase angles, spokes appear bright relative to surrounding ring particles.
The NASA website hosts a large number of images from the Soviet/Russian space agency, and other non-American space agencies. These are not necessarily in the public domain.
The SOHO (ESA & NASA) joint project implies that all materials created by its probe are copyrighted and require permission for commercial non-educational use. [2]
{{Information |Description=Dark spokes dance around Saturn's B ring in this series of movies comprised of images taken with Cassini's wide-angle camera. This animation is from the sequence taken on
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