Venus South Pole Roils With Fickle Storm

Scientists aren't sure what is causing the phenomenon. Colin Wilson, with the University of Oxford, theorizes that atmospheric gases are being heated by the sun at Venus' equator rise and shift toward the poles, where they then regroup and sink back down again.

"As the gases moves toward the poles, they are deflected sideways because of the planet's rotation," Wilson said.

Viewed in the infrared -- Venus' atmosphere is too dense for imaging details in visible light -- the core of the vortex appears very bright, indicating a region hotter than its surrounding environment.

The downward shift of gases would create a depression at the cloud tops, making the region hotter, scientists said.

"The vortex is similar to what you might see in your bathtub once you have pulled out the plug," said Giuseppe Piccioni, a lead scientist on the Venus Express program.

The spacecraft already has surpassed its design life of 500 Earth days, or two Venus years, with studies continuing. Scientists are trying to figure out why Venus, Earth and Mars, which are about the same size and composition, evolved into such different worlds and whether life ever took hold anyplace else besides Earth.

Related Links:

Irene Klotz's blog: Free Space

ESA's Venus Express

How Stuff Works: Venus