Editor's Summary

13 December 2007

Saturn's other ring

The idea that there is a ring current of trapped particles encircling the Earth at high altitudes first emerged in the early part of the twentieth century. The idea proved right, and measurements of the current's extent and composition were made in 1957. Ring currents of a different nature were later observed at Jupiter and inferred at Saturn. The magnetospheric imaging instrument on the Cassini probe has now obtained images of the ring current at Saturn. The current is highly variable, with strong longitudinal asymmetries that corotate nearly rigidly with the planet. This contrasts with Earth's ring current, where there is no rotational modulation and initial asymmetries depend on local effects.

Letter: A dynamic, rotating ring current around Saturn

S. M. Krimigis, N. Sergis, D. G. Mitchell, D. C. Hamilton & N. Krupp

doi:10.1038/nature06425

First paragraph | Full Text | PDF (1,931K) | Supplementary information