Ringing the Changes

摘要

It all seemed so simple for a while. As far as we knew, Jupiter, Saturn, Uranus, and Neptune each had a ring system, a suite of small moons orbiting just beyond or close to the rings, followed by an impressive set of large moons and finally an irregular collection of outer moons in eccentric, inclined orbits. But now Uranus has yielded a few more secrets in the form of new moons and new rings. The moons may be tiny and the rings faint, but the research reported by Showalter and Lissauer on page 973 of this issue reveals a complicated, evolving system that provides a fascinating insight into how rings and small moons are inextricably linked.