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"It is the fastest riser on record," says Ron Moore, an astronomer at NASA's Marshall Space Flight Center in Huntsville, Ala. So fast, in fact, that astronomers are betting on 1990 or perhaps even later this year, instead of 1991, as the beginning of the maximum. And what a maximum it could be. Despite the ferocity of the March flares, Moore warns, "this cycle is still in its early phase. It's got quite a way to go." Solar buffs are speculating it might approach the violence reached by the 1957-58 maximum, which touched off five disruptive geomagnetic superstorms and vivid auroral displays. Says astronomer Donald Neidig at the National Solar Observatory outpost on Sacramento Peak, near Sunspot, N. Mex.: "We can't rule out a record breaker."
In anticipation of the fireworks, astronomers scheduled a two-week, worldwide solar-observation period during the second half of June. The project was timed to benefit from the observations of the Solar Maximum Mission satellite (nicknamed Solar Max) before it plunges to its death. Lofted into earth orbit in 1980 to monitor the sun's activity, the satellite is gradually descending and will probably re-enter the earth's atmosphere in November and be incinerated. Solar Max's readings of the sun's activity were coordinated with observations made all over the world by ground-based telescopes and instruments mounted on high-flying rockets. A hundred solar centers around the globe were linked by an electronic-mail network designed to provide the latest data on the sun's behavior.
A major goal of the project was to catch a flare in the act, mapping all the solar high jinks associated with it from beginning to end. The sun's timing could not have been better. During the first week of observations, it set off several large flares and ejected billions of tons of matter in a prominence that extended more than 200,000 miles into space.
The intense solar observations should provide clues to many of the still unanswered or only partly resolved questions about the sun: Does the solar cycle affect terrestrial weather? What internal mechanisms control the cycle? Is the sun growing cooler? Hotter? Is there a basic flaw in the current theory about the fusion process that powers the solar furnace?
While the recent flares did not measure up to the March conflagration, astronomers were jubilant. "We have been exceptionally lucky," says Alan Kiplinger, a solar physicist at the University of Colorado. "It's unusual to have the sun cooperate."
Fortunately for earth dwellers, the March flare occurred on the easternmost edge of the sun and thus aimed its full force away from the earth. But on March 10, when the sun's stately rotation brought the turbulent group of sunspots to a position more directly facing the earth, a second, only slightly less powerful flare erupted in the region. Eight minutes later, traveling at the speed of light, a blast of X ray and ultraviolet radiation seared the earth's upper atmosphere. Within an hour, high-energy protons began to arrive, followed in three days by a massive bombardment of lower-energy protons and electrons.