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Looks like Sol is back on the radar screen again. Seems it's three weeks later and our nearby star hasn't calmed down. The Thursday they're talking about here is Thanksgiving Day:
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As the sun acts up, experts see trouble
Anahad O'Connor NYT
Tuesday, November 25, 2003

Flares pose threats close to Earth

BOULDER, Colorado Snapping like rubber bands pulled too tight, tangled magnetic fields on the surface of the sun have been spewing waves of radiation and superheated particles at Earth.

So far, the damage has been relatively minor compared with the significant communications disruptions that occurred three years ago. The culprits this year are three volatile sunspots that began erupting last month. They have set off blackouts in Sweden, damaged satellites and forced some airlines to divert flights away from polar routes to escape extra radiation.

And now, after a three-week lull while the sun's rotation spun them out of view, the sunspots are back within striking distance. The one with the potential to produce the most fireworks, Region 507, is expected to fix its sights squarely on Earth on Thursday. While all three sunspots have decayed a bit, 507 is still roughly eight times as large as Earth.

Predicting the level of havoc that can be brought on by 507 or any other exploding sunspot is a minute-to-minute science. The erratic nature of exploding sunspots leaves researchers with as little as 30 minutes to warn of radiation storms or as much as 17 hours to prepare for speeding clouds of plasma.

And nowhere perhaps is the pressure greater to assess the magnitude of these blasts than within the walls of the Space Environment Center here, home of what could be called the solar storm trackers.

Vivid, up-to-date images of the sun captured by satellites millions of miles away constantly blare across an elevated, oversize television screen demanding the team's attention.

To the forecasters here, every sunspot has its own personality and can be dangerously unruly or quickly fizzle into obscurity.

For the last month, the rotating team of several space weather forecasters at the National Oceanic and Atmospheric Administration has focused on nothing else, their eyes darting from computer images of the sun flares to e-mail messages and phone calls in an effort to warn thousands of businesses and agencies like utilities, NASA, the military and the airlines of the newest storm ratings.

They also respond to queries and comments from the public that range from the humorous (one woman blamed a flare for a speed-trap radar reading of 90 miles, or 145 kilometers, per hour) to the tragic (some feared that pacemakers would fail in such events). Or those who complain the hair on their arms stands on end. Or that a homing pigeon loses its internal compass in a geomagnetic storm.

Last Thursday, when the sunspots reappeared with a new round of storms, the space forecasters fell back into formation. A locustlike cloud of charged particles shot out of the sun at over 2 million miles per hour, swarming Earth just after midnight.

Standing beside a fortress of computers, William Murtagh, one of the forecasters, described the storm as relatively slow-moving. Still, he brimmed with the satisfaction of knowing that at least for the day, he had tried to mitigate the sun's devastating fury.

"This one we predicted would arrive in 50 hours, and it actually reached us in 46 - so I'd say that's a pretty good job," he noted with a smile. "We expected major to severe geomagnetic storm levels, and that's exactly what we're getting now - right on target."

Those predictions have far-reaching effect.

The storm trackers' alerts prompted power companies throughout North America to switch into "safe mode," to protect any grids from collapse with the heightened currents of a solar storm. All it took to plunge six million people in Quebec into darkness during a storm in March 1989, Murtagh says, was one transformer that overheated and shut down.

The frenetic activity in the forecast center Thursday was only a glimpse of what could come this week, when Regions 507 and 508 stare at Earth. As 508 was rotating away from Earth on Nov. 4, it unleashed a flare that some scientists said was the biggest explosion ever recorded in the solar system.

"It was like being in Miami and seeing a giant hurricane coming toward you that eventually veers off to sea," said Devrie Intrilligator, director of the space plasma laboratory at the Carmel Research Center in Santa Monica, California. "We really lucked out because the full force of it didn't head toward Earth."

When it was tucked away on the backside of the sun, 508 ejected clouds of plasma so enormous that scientists could see them dwarfing the sun in size as they roared off into space. Now it is Region 507 that Murtagh and his team are bracing for. Rivaling Jupiter in size, it has the potential to bathe Earth once again with intense storms that could expose airplane passengers flying around the Thanksgiving holiday to abnormal amounts of radiation.

The last time that happened, in late October, the Federal Aviation Authority warned passengers on aircraft over 25,000 feet, or 7,620 meters, at some latitudes that they would accumulate about two millirems of radiation per hour, or two days' worth of radiation on the ground.

The forecasters can be on 24-hour call at particularly volatile times like these. Murtagh recalled talking to an airline from bed at 11 p.m. one day as the company tried to decide whether to proceed with a flight from Newark, New Jersey, to Beijing the next day.

Now and then, even the forecasters are dumbfounded by the connections people draw between the force of the solar storms and everyday life.

Murtagh said he was reluctant to rule anything out. But, he added, "If someone did a study showing geomagnetic storms affect radar guns, you can be sure the legal system would be flooded with millions of people fighting traffic tickets."

The New York Times

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