The Uranian Rings

Updated May 8, 2019 | Infoplease Staff

Voyager 2 also expanded the body of information pertaining to the rings and moons of Uranus. Voyager's cameras obtained the first images of 9 previously known narrow rings and discovered at least 2 new rings, one narrow and one broadly diffused, bringing the total known rings to 11. It was found that a highly structured distribution of fine dust exists throughout the ring system.

The outermost (epsilon) ring contains nothing smaller than fist-sized particles. It is flanked by two small moons discovered interior to the orbit of the Uranian moon Miranda. The moons exert a shepherding influence on the epsilon ring and on the outer edges of the gamma and delta rings.

All of the rings lie within one planetary radius¹ of Uranus's cloud tops. Most of Uranus's rings are narrow, ranging in width from 0.6 to 58 mi (1 to 93 km), and are only a few kilometers thick. The Uranian rings are colorless and extremely dark. The dark material may be either irradiated methane ice or organic-rich minerals mixed with water-impregnated, silicon-based compounds. There is evidence that incomplete rings, or “ring arcs,” exist at Uranus.