04. A Dynamic Place
Joseph Burns
Joseph A. Burns, Theoretical and Applied Mechanics/Astronomy, and fellow researchers caught new views of Saturn and its rings as NASA’s Cassini spacecraft passed behind Saturn’s shadow in September 2006. This is the first time that scientists have seen the entire ring system. The images reveal faint new rings in the system, including two orbiting with their small parent moons outside the main ring system and two within the Cassini Division, the largest gap in the main ring system, named after its seventeenth-century discoverer Giovanni Cassini. The spacecraft also photographed a dynamic rippled pattern in the system’s innermost D ring. The new images show how Saturn’s ring system is changing over time. A new ring in the Cassini Division, which is not visible in images from NASA’s 1980s Voyager mission, has emerged. Another example is the outer part of the D ring, a series of closely spaced ringlets. While investigating whether the D ring is vertically warped, researchers compared Cassini’s images with Hubble Space Telescope images from 1995 and discovered a change. The research on Saturn’s moons and their interactions with the rings will help scientists understand how the moons formed—and might reveal how the Saturn system formed.