Storms on Uranus are building, and beginning to encircle the world, baffling boffins who wonder how these systems can form on such a frigid world. The region where the storms are seen is currently experiencing winter conditions, adding to the mystery.
Imke de Pater, chair of the astronomy department at the University of California, Berkeley, led a group of astronomers at the Keck Observatory in Hawaii who made the discovery. His team recorded eight large storms in the northern hemisphere of the gas giant in infrared light.
"This type of activity would have been expected in 2007, when Uranus's once-every-42-year equinox occurred and the sun shined directly on the equator. But we predicted that such activity would have died down by now. Why we see these incredible storms now is beyond anybody's guess," Heidi Hammel from the Association of Universities for Research in Astronomy, said.
One of the storms was one of the most powerful ever witnessed on the planet, as seen at a wavelength of 2.2 microns. The tempest reflected almost a third of the light at this wavelength as the entire rest of the planet. This frequency of light allows astronomers to view formations in the lower stratosphere of Uranus. At this altitude, the atmospheric pressure is roughly half that on Earth, at sea level.
Amateur astronomers in France and elsewhere were able to record the images, using techniques and equipment not available even a few years ago.
"I was thrilled to see such activity on Uranus. Getting details on Mars, Jupiter or Saturn is now routine, but seeing details on Uranus and Neptune are the new frontiers for us amateurs and I did not want to miss that," Marc Delcroix, a French amateur astronomer who recorded images of the storm, said.
The storms seen on Uranus may extend deep into the atmosphere, similar to massive whirlpools seen on Jupiter, including the Great Red Spot.
The Hubble Space Telescope was utilized to take images of the planet, over a wide range of wavelengths, on October 14. The space observatory revealed powerful storms spread over the alien world, at a multitude of depths.
Uranus has a diameter of roughly 31,500 miles, roughly four times that of Earth, and the third-largest in the Solar System. orbiting around the Sun at a distance of 1.8 billion miles, the planet was discovered by astronomer William Herschel in 1781.
Massive storms on Uranus and study of the features on that distant world was detailed in a talk delivered at a meeting of the American Astronomical Society's Division of Planetary Sciences on November 12.