At 2.2 microns, methane and hydrogen in Uranus' atmosphere absorb most of the sunlight falling on the planet, so little is reflected back into space. Imaging at this wavelength results in a dark Uranus, making the faint ring system clearly visible. A sheet of material interior to rings 4, 5, and 6 is a broad, dusty ring seen for the first time since the 1986 Voyager encounter. This near-infrared image was taken with adaptive optics on Keck II in July 2004.
Imke de Pater, Seran Gibbard, and Heidi Hammel