Newswise — Look closely at a giant planet like Jupiter and you can actually see a powerful system of winds at work right on the surface. University of Alberta physicist Dr. Moritz Heimpel and his research team have created a new three-dimensional computer model to describe how the winds that form the distinctive bands on that planet's surface are powered by forces from within the planet.

The research is published in the current issue of "Nature."

Heimpel has always been interested in planetary dynamics, especially in the core of the earth, and how it generates a magnetic field. We cannot directly see what is going on in the earth's core, but with the big planets like Jupiter and Saturn, fluid dynamics can be seen right on the surface. "We have images from space missions that show fluid motion in incredible detail," said Heimpel. "The giant planets provide a natural laboratory for the fluid dynamics of other planetary bodies."

The model is the first to show that high latitude jet streams come from deep convection. The issue of how deep these fast winds penetrate—their speeds reach upwards of 340 miles per hour, twice as rapid as hurricane-force winds--has always been an unresolved question. Some groups have argued that the winds are shallow and powered by the sun, and others have maintained that the winds are deep and powered by the internal heat of Jupiter itself. Heimpel's model gives strong evidence of a deep origin of Jupiter's winds.

On a small scale, an example of fluid dynamics takes place in a creek with little whirls of current. The research team—made up of Johannes Wicht from the Max Planck Institute for Solar System Research in Germany and Jonathan Aurnou at the University of California, Los Angeles—had to scale that small example up to planetary size. The key, said Heimpel, was using a good computer system and a better code as well as a scaling theory for planetary turbulence.

The research may provide answers about the flow in the liquid outer core of the earth, and for zonal--longitudinally-directed--currents in the Earth's oceans.

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Nature (Nov-2005)