By Ron Cowen
Even at its quietest, the sun about once a week belches out a billion-ton cloud of charged particles and magnetic fields. When those eruptions are directed toward Earth, they can irradiate astronauts, disable satellites, and knock out power grids on the planet.
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This week, scientists announced that they have developed a new computer model for forecasting the frequency and strength of these solar storms, which tend to follow an 11-year cycle. The sun is currently near the low point of its activity. The model predicts that solar activity won’t begin rising until late 2008—as much as a year later than the sun’s standard cycle would forecast. Furthermore, the next entire cycle of solar activity will be 30 to 50 percent stronger than the current one, according to the new model.