September 11, 2012
Cassini Reveals Clumping In Saturn’s B-ring
April Flowers for redOrbit.com - Your Universe Online
The European Space Agency (ESA) released an image of Saturn's rings on Monday provided by NASA's Cassini spacecraft. Clumpy particles in the B-ring are in stark contrast to the delicately ordered ringlets of the rest of Saturn's rings.
The moon, Mimas, which orbits Saturn once during every two rotations of the icy ring particles, influences the ring's outer edge. These periodic gravity disturbances are thought to compress the ring particles into clumps, while maintaining the ring's well-defined outer edge.
William Herschel discovered Mimas in 1789. It is the twentieth-largest moon in the Solar System, with a diameter of 396 kilometers and is the smallest astronomical body that is known to be rounded due to self-gravitation.
The Huygens gap, the widest dark void visible in this image, lie beyond the B-ring and is punctuated by the bright Huygens ringlet. The 4800 kilometer wide Cassini Division separates the B-ring from the outermost A-ring, but is itself marked out with faint, concentric strands of ring material.
From Earth, the delicate structures of the Cassini Division cannot be seen, but close-up views from spacecraft reveal them in fine detail.
This image was taken in visible light with the Cassini spacecraft narrow-angle camera on 10 July 2009 from a distance of 320 000 km from Saturn.
Cassini is a joint mission between ESA, NASA and the Italian Space Agency and has been in orbit around Saturn since 2004. It is now in its second extended mission phase, the Cassini Solstice Mission, which will continue until 2017.