Cloudy puzzle on Uranus

Shrouded in darkness for 20 years, the northern hemisphere of Uranus is slowly emerging from the shadows. With sunlight once again illuminating the planet’s northern face, astronomers are taking their first peek at a region on Uranus that they have never before seen with modern detectors.

Observers have been astonished to find that the planet’s atmosphere, thought to be bland and nearly featureless, contains several enormous bands of bright clouds (SN: 11/29/97, p.