Stormy Weather Brewing on the Sun

By Maia Weinstock|Sunday, September 01, 2002
Temperatures hover between 10,000 and 300,000 degrees Fahrenheit, and the "air" is mostly ionized hydrogen, but the billowing outer layers of the sun have weather patterns strangely reminiscent of those on Earth. Using data from the SOHO spacecraft, Deborah Haber and Brad Hindman of the University of Colorado have discovered gentle winds, jet streams, and vast hurricanes whose raging may eventually make itself felt here, 93 million miles away.

A map of subsurface flows on the sun (blue arrows) shows the equivalent of trade winds and hurricanes.
Photograph courtesy of NASA/ESA/SOHO/University of Colorado, Boulder

Drawing on the relatively new science of helioseismology— the study of acoustic oscillations that make the sun ring like a bell— researchers recently presented the first proof of subsurface solar winds, ranging from 45-mile-an-hour breezes to 100-mile-an-hour swirling storms. Haber and Hindman even detected a major shift of the wind in the sun's northern hemisphere, reminiscent of the El Niño weather pattern on Earth. "Our technique sees these large flows moving up, cooling, and moving back down again at all different scales. We really don't know what's causing them," Haber says.

Six years of SOHO measurements, which record the velocity and direction of solar acoustic waves, allowed Haber and Hindman to reconstruct large-scale gas flows from the sun's surface down to 9,000 miles beneath it. The scientists then used this information to create three-dimensional maps of these weather systems. The motions in this denser part of the sun may trigger large-scale space-weather events up above. These powerful outbursts fling clouds of charged particles into space, pummeling Earth's magnetic field and sometimes causing damage to Earth-orbiting satellites. Haber and Hindman's findings dovetail with the near-simultaneous, independent discovery of weather patterns on brown dwarfs, or failed stars. Together the evidence suggests that weather is ubiquitous on planets, stars, and everything in between.

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