Discoveries in Saturn's Dark
October 12, 2006
by David Tytell
In this unique view, the Cassini orbiter observed Saturn while its cameras were hidden in the planet's shadow.
NASA/JPL/Space Science Institute
It's amazing what a change of perspective can do. Just ask astronomers working with NASA's Cassini spacecraft. On September 15th, the Saturn orbiter found itself in a rare position — deep within a Saturnian eclipse. For about 12 hours the craft observed the ringed world from within the planet's shadow. In the unique image at right, the Sun is directly behind Saturn and the rings shine in scattered, rather than reflected, light. From this point of view small particles in the rings appear especially bright, much the way that cobwebs look brighter when lit from behind.
Such a perspective reveals many new things. First off, the team uncovered two new rings made of tiny dust particles, and they confirmed the existence of a couple others. Second, rings and moons are intertwined. "When you see a ring, there is likely to be a satellite," says Joe Burns (Cornell University). Sure enough, one of the finds is associated with the moonlets Janus and Epimetheus, and a second overlies the orbit of a tiny moon called Pallene.