BERKELEY, Calif., Nov. 13 (UPI) -- Normally, the smooth blue surface of Uranus denotes a soothing, deep-space serenity. Being the seventh planet from the sun, its temperatures are cool -- it's a so-called ice giant -- and its main chemical components (hydrogen, helium, water, ammonia and methane) all play nicely with each other.

But recently, astronomers have noticed several high-powered storms swirling across the planet's surface, befuddling onlookers accustomed to an uninterrupted sphere of pale, greenish-blue. According to imagery collected by Hawaii's Keck Observatory, as well as the Hubble Telescope, Uranus currently features eight distinct storms. One of them is the largest astronomers have ever seen on the planet.


"The weather on Uranus is incredibly active," Imke de Pater, an astronomer at the University of California, Berkeley, who led the recent research, said in a press release.

"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," added co-investigator Heidi Hammel, a scientist at the Association of Universities for Research in Astronomy. "But we predicted that such activity would have died down by now. Why we see these incredible storms now is beyond anybody's guess."

Because there's no internal heat source inside Uranus, scientists have assumed its storms are driven solely by the warming of the sun. But with Uranus's northern hemisphere now facing away from the sun, the effects of solar heating should have faded. Instead, Uranus -- which lies some 1.78 billion miles from the sun -- continues to boast extreme storms.

"Predictions said they should fade away but they didn't," de Pater told attendees at the American Astronomical Society's Division for Planetary Sciences in Tucson, Arizona, this week. "And we hope theorists will now take this mystery on and help explain what exactly is going on."