EYES ON THE STORM-TOSSED SUN

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If you think hurricanes and tornadoes are powerful, take a look at the sun's periodic storms. Kicking up twisting arcs of fiery gases, solar eruptions from that great thermonuclear reactor in the sky can stretch as far as the distance from Earth to the moon. The most intense outbursts explode a billion tons of material off the sun's searing (11,000[degrees]F) surface at speeds of millions of miles an hour. If these electrically charged particles happen to slam against Earth's atmosphere, they can imperil astronauts, push satellites out of orbit or fry their circuitry. If they hit the ground, they can turn compass needles topsy-turvy, knock out electrical-power systems and possibly change the planetary climate. No wonder scientists dream of one day being able to predict storms on the sun with all the accuracy of terrestrial weather forecasts.

Last week they seemed a little closer to getting their wish. At a meeting of the International Astronomical Union in Kyoto, Japan, and at a special NASA briefing in Washington, solar physicists ecstatically reported results from a new generation of solar observatories--a NASA-European Space Agency satellite known as soho (for Solar and Heliospheric Observatory), which has been circling the sun since December 1995, and the National Science Foundation's global network of ground-based solar stations. By keeping a day-to-day eye on solar weather features such as the sun's "trade winds" and "jet streams," these new high-tech observatories are creating what the assembled researchers hailed as a revolution in their field. An exultant John Leibacher, director of the NSF solar program, said, "I have been [observing the sun] for 40 years, and I never had any hope that we would be able to see these things."

What they saw included an astonishing doughnut-shaped jet stream of hot gases circling the sun's "Arctic" region, like Earth's own circumpolar winds. The scientists were so taken aback by the fast-moving river of plasma, they said, that they dared not reveal their findings until they had rechecked their data several times. The scientists also got a close-up look at the sun's lower-latitude trade winds, whose existence they had hitherto only suspected. The new probes not only confirmed these suspicions but also showed that the winds--actually, great bands of plasma slightly warmer than neighboring solar gases--dive deep into the solar interior, itself a mass of gases, then flow back toward the equator, creating a circular gyre reminiscent of Earth's great ocean currents, such as those that sweep the Atlantic and Pacific. "We used to think the inside of the sun was fairly simple," says John Harvey, an astronomer at the Kitt Peak National Observatory near Tuscon, Ariz. "But that was before we had the capability to see into it."