A panel of solar experts announced today that the sun should be taking it easier on humans and their myriad electronic devices than some scientists had warned. Rather than soaring toward record levels, sunspots--and by inference their accompanying disruptive solar storms--will most likely increase to near-average peak levels by 2012. But in a sign of continuing scientific uncertainty, panel members could not agree on whether sunspots would be somewhat above or below average.
Sunspots are areas of intense magnetic activity on the solar surface. When debris from associated energetic eruptions reach Earth, they can fry orbiting electronics as well as disrupt systems on the ground. In 1996, an expert panel sponsored by NASA and the National Oceanic and Atmospheric Administration (NOAA) predicted that maximum sunspot activity for the year 2000 would reach a lofty 160 events. It turned out to be a near-average 120.
This time around, the 12 panel members had results from sophisticated computer models simulating how the sun generates sunspots. In the models, at least, the powerful magnetic fields that shape sunspots are recycled deep into the interior before being reintensified to give rise 20 to 30 years later to another sunspot maximum. One of these models drew considerable attention last year (ScienceNOW, 6 March 2006) when its operators predicted an ominous peak of 155 to 180 events.
But the activity is not likely to be that dramatic, according to this year's panel, which had to issue two solar max predictions. "The panel is split down the middle on whether it will be bigger than average [sunspot number of 140] or smaller than average ," said panel chair Douglas Biesecker of the Space Environment Center in Boulder, Colorado. On the positive side, the peak "will not be at one of the extremes," added space physicist Daniel Baker of the University of Colorado, Boulder. That means operators of systems susceptible to solar disruption--from power grids to the Global Positioning System--can now ignore "a lot of the noise coming from scientists," who have been predicting everything from a real snoozer of a solar maximum to a catastrophic peak, says panel member Joseph Kunches of NOAA's Space Environment Center.
The panel expects to home in on a single number within the next year or so, but this latest effort could eventually yield a scientific bonus: a firmer grasp of the inner workings of the sun.