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The Resurgent Sun
Evidence Is
Mounting That Some |
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Every 11 years solar activity reaches a fever pitch: Solar flares erupt near sunspots on a daily basis. Coronal mass ejections, billion-ton clouds of magnetized gas, fly away from the Sun and buffet the planets. Even the Sun’s awesome magnetic field —as large as the solar system itself — grows unstable and flips. It’s a turbulent time called Solar Max. The most recent (and ongoing) Solar Max crested in mid-2000. Sunspot counts were higher than they had been in 10 years, and solar activity was intense. One remarkable eruption on July 14, 2000 — the so-called “Bastille Day Event” — sparked brilliant auroras as far south as Texas, caused electrical brownouts, and temporarily disabled some satellites. After that, sunspot counts slowly declined and the Sun was relatively quiet for month-long stretches. Solar Max was subsiding. But as we’re now halfway into 2002, it’s back. The Sun is again peppered with spots, and eruptions are frequent. Says David Hathaway, a solar physicist at the NASA Marshall Space Flight Center, “The current solar cycle appears to be double-peaked,” and the second peak arrived earlier this year. |
Sunspot counts for the current solar cycle peaked in mid-2000 and again late last year. (Image courtesy David Hathaway, NASA/MSFC.) |
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International sunspot counts between 1975 and 1995 show that the last two sunspot cycles also had double-featured maxima. |
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