Washington: Astronomers have recently observed extreme storms on Uranus, with enormous cloud systems so bright that the details in the planet's hazy blue-green atmosphere can clearly be seen.

Imke de Pater, professor and chair of astronomy at the University of California, Heidi Hammel of the Association of Universities for Research in Astronomy and their team detected eight large storms on Uranus's northern hemisphere when observing the planet with the Keck Observatory on August 5 and 6.

One was the brightest storm ever seen on Uranus at 2.2 microns, a wavelength that senses clouds just below the tropopause, where the pressure ranges from about 300 to 500 mbar, or half the pressure at Earth's surface. The storm accounted for 30 percent of all light reflected by the rest of the planet at this wavelength.

Larry Sromovsky, a planetary scientist at the University of Wisconsin, said that the colors and morphology of this cloud complex suggested that the storm might be tied to a vortex in the deeper atmosphere similar to two large cloud complexes seen during the equinox.

An expanded team of astronomers led by Kunio M. Sayanagi, an Assistant Professor at Hampton University in Virginia, leveraged the amateur observations to activate a "Target of Opportunity" proposal on the Hubble Space Telescope, which imaged the entire planet on Oct. 14. Observing at a variety of wavelengths, HST revealed multiple storm components extending over a distance of more than 9,000 kilometers (5,760 miles) and cloud s at a variety of altitudes.