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Solar Flare May Spawn Disruptive Magnetic Storm

October 29, 2003|Usha Lee McFarling | Times Staff Writer

One of the most powerful solar flares in nearly 30 years erupted from the sun's surface early Tuesday morning, ejecting a titanic blast of gas, radiation and matter toward Earth.

Space weather forecasters said the event could lead to a geomagnetic storm today and Thursday that could disrupt power lines and impair satellite and radio communications, although the power of the storm remained uncertain.

"This one is aimed right at Earth and it's the largest Earth-directed event we've ever seen," said John Kohl, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics in Cambridge. "This is the real thing."

Solar storms occur when the protective magnetic bubble surrounding the Earth is buffeted by huge magnetic fields and streams of high-energy particles torn from the surface of the sun. Such solar explosions are almost unimaginably violent: They can carry the power of 40 billion atom bombs, spew billions of tons of material and travel through space at speeds of 3 million mph.

Tuesday's solar flare was the third-largest recorded since 1976, Kohl said. The two largest flares occurred in 1989 and 2001, but caused few problems because they were pointed away from Earth.

The new flare appears to be on a collision course with our planet. "We're going to get the full brunt of this one," said Joe Kunches, chief of the Space Weather Operations Center at the National Oceanic and Atmospheric Administration's Space Environment Center in Boulder, Colo.

Kunches predicted a severe geomagnetic storm rated G4 using NOAA's space storm scale, which ranges from mild (G1) to extreme (G5). He said periods of G5 storming were possible.

G5 storms can render satellites useless and disrupt communications and navigation systems. Storms in the last 15 years have disabled satellites, leaving pagers, automatic teller machines and some airline communications crippled.

The flare is 100 times stronger than the solar flare that reached Earth last week and did little damage. A solar storm in March 1989 that knocked out power throughout the province of Quebec was a result of the fourth most powerful flare recorded.

The impact of the storm could be less serious than expected because forecasters cannot determine the size of the magnetic field heading toward Earth or its orientation -- two factors that influence the destructive power of a storm, Kunches said.

In addition, those who manage power grids, maintain satellites and route aircraft can take steps to reduce risks during extreme events, he said.

The astronauts aboard the international space station, for example, have moved into the most shielded portion and will remain there until all radiation threats have passed.

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