An Evolving View of Saturn’s Dynamic Rings
Clark, R. N.; Nicholson, P. D.; Kempf, S.; Srama, R.; Hedman, M. M.; Burns, J. A.; Showalter, M. R.; French, R. G.; Spilker, L. J.; Schmidt, J.; Charnoz, S.; Sremčević, M.; Porco, C. C.; Spitale, J. N.; Murray, C. D.; Colwell, J. E.; Esposito, L. W.; Filacchione, G.; Dones, L.; Cuzzi, J. N.; Tiscareno, M. S.; Marouf, E. A.; Weiss, J.
United States, France, Italy, Germany, United Kingdom
Abstract
We review our understanding of Saturn’s rings after nearly 6 years of observations by the Cassini spacecraft. Saturn’s rings are composed mostly of water ice but also contain an undetermined reddish contaminant. The rings exhibit a range of structure across many spatial scales; some of this involves the interplay of the fluid nature and the self-gravity of innumerable orbiting centimeter- to meter-sized particles, and the effects of several peripheral and embedded moonlets, but much remains unexplained. A few aspects of ring structure change on time scales as short as days. It remains unclear whether the vigorous evolutionary processes to which the rings are subject imply a much younger age than that of the solar system. Processes on view at Saturn have parallels in circumstellar disks.