Science + Technology

Jupiter’s Massive Winds Likely Generated From Deep Inside Its Interior, Scientists Report


A new computermodel indicates Jupiter's massive winds are generated from deep within thegiant planet's interior, a UCLA scientist and international colleagues reporttoday in the journal Nature.

Jupiter'spowerful winds are very different from those on Earth. They continually circlethe planet, and have changed very little in the 300 years that scientists havestudied them. Massive east-west winds in Jupiter's equatorial region reachapproximately 340 miles per hour — twice as rapid as winds generated by stronghurricanes on Earth. At higher latitudes, the wind pattern switches toalternating jets that race around the planet.

No one has beenable to explain why the winds are so constant or what generates them — but thatmay change.

"Our model suggests convectiondriven by deep internal heat sources power Jupiter's surface winds," saidJonathan Aurnou, UCLA assistant professor ofplanetary physics. "The model provides a possible answer to why the winds areso stable for centuries. Jupiter's surface is the tail; the dog is the hotinterior of the planet.

"On Earth," Aurnou said, "weget strong changes in wind patterns every season. On Jupiter, there is almostno variation. There are changing cloudstructures, but the large-scale winds remain essentially constant."

The researchersidentified key ingredients that explain Jupiter's "super winds" and factoredthose into their model. Aurnou's colleagues are Moritz Heimpel,assistant professor of physics at the University of Alberta in Edmonton, andJohannes Wicht at the Max Planck Institute for SolarSystem Research in Germany.

Aurnou, Heimpel and Wichtcreated the firstthree-dimensional computermodel that generates both a large eastward equatorial jet and smalleralternating jets at higher latitudes. In a rapidly rotating shell of fluid,they modeled thermally driven convection, which is what drives motion in a boiling pot.

"Three critical ingredientsare the correct geometry, turbulent convection and rapid rotation, and ourmodel contains all three elements," said Aurnou, afaculty member in UCLA's Department of Earth and Space Sciences. "When youinclude all those, that gives us the right recipe. In the future, we'll refine our model by adding even more ingredients."

Jupiter's radiusis more than 11 times the radius of Earth. A tremendous amount of heat comesfrom the interior.

"The heat fromJupiter's interior is comparable to the heat the planet receives from the sun,"Aurnou said.

The modelsuggests three-dimensional convection in Jupiter's deep atmosphere is likelydriving the zonal flows, Aurnou said.

Jupiter'sinterior is made primarily of compressed hydrogen and helium, and a giantplasma.

Aurnou will continue to study Jupiter's strong winds, as well as thoseon Saturn, Uranus and Neptune.



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