Jupiter's Cloud Bands Driven by Thunderstorms, Study Suggests

The jet streams that give Jupiter its colorful cloud bands may extend thousands of miles into the planet's interior, according to a new study.

The jets are driven by sunlight, turbulence and thunderstorm activity, the thinking goes.

Jet streams on Earth flow eastward at mid-latitudes. Airliners fly faster with them and slower when heading West. They control much of the Northern Hemisphere's weather.

Similar jet streams race around Jupiter, Saturn, Uranus, and Neptune. On Jupiter, they blow at up to 400 mph. Since detailed images were returned by the Pioneer and Voyager spacecraft in the 1970s, scientists have pondered the exact mechanism that drives them.

With new computer simulations, scientists found that temperature contrasts fueled by sunlight or thunderstorm activity produce multiple jet streams, just as those seen at Jupiter.

And they may run much deeper than thought.

"Most planetary scientists have assumed that jets pumped near the top of the atmosphere will remain confined to those shallow layers, and we've shown that this is not a valid assumption," said study leader Adam Showman of the University of Arizona in Tucson.

Previous measurements found strong winds nearly 100 miles (150 kilometers) below the cloud tops. Many scientists had thought this meant the jets are driven from deep inside Jupiter's interior.

The new study challenges that interpretation.

"We still don't know whether the jets on the giant planets are driven from the top or within the deep interior," Showman said. "But our study shows that the deep winds measured by the Galileo probe could just as easily result from shallow cloud-layer turbulence as from turbulence deep inside Jupiter's interior."

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