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Sun Flare Causes Strong Geomagnetic Storm, Few Problems

The most powerful such event since 1989 disrupts airline communications in north, but little else.

October 30, 2003|From Times Staff and Wire Reports

DENVER — A powerful geomagnetic storm walloped the Earth early Wednesday, knocking out some airline communications but apparently causing no large power outages or other major problems.

The storm, the most disruptive to hit Earth since 1989, was unleashed by the fourth-most powerful solar flare ever recorded, NASA scientists said.

The gigantic cloud of highly charged particles hurled from the sun posed a threat to electric utilities, high-frequency radio communications, satellite navigation systems and television broadcasts.

Solar astronomers said Wednesday that a second major solar flare had exploded and was also heading directly toward Earth. It was expected to cause additional days of geomagnetic storming.

"It's like looking right down a gun barrel," said John Kohl, a solar astrophysicist at the Harvard-Smithsonian Center for Astrophysics.

Kohl said that fast-moving material from the second flare could hit the Earth's magnetic field while slow-moving material from the first flare was still arriving, compounding potential problems. He said the odds of two solar flares hitting the Earth at one time were so low that astronomers had not even bothered to calculate them.

The biggest effect Wednesday was the blackout of high-frequency voice-radio communications for planes flying far northern routes.

But airliners in an emergency could still communicate through VHF contact with another aircraft or military monitoring station, said Louis Garneau, a spokesman for the company that handles Canada's civil aviation navigation service.

British controllers were keeping transatlantic jets on more southerly routes than usual to avoid the problem.

The particle storm was rated a G5, the highest intensity on scientists' scale of space weather. Space observers have measured G5 storms five times in the last 15 years, but few, if any, have hit Earth so directly.

It whipped through the solar system at about 5 million mph, taking just 19 hours to travel the 93 million miles from the sun to envelop the planet. Federal scientists said it collided with Earth's magnetic field at 1:13 a.m. EST on Wednesday, about 12 hours earlier than predicted.

Last week, a weaker solar flare erupted on the sun's surface, but scientists said the particle cloud from that event largely spared the planet.

Such storms pose no direct threat to people on the ground because the Earth's thick atmosphere deflects and absorbs incoming charged particles. But the storm may produce colorful auroras in the northern night sky visible as far south as El Paso, beginning late Wednesday.

The last time a G5 storm hit Earth was in 1989. It damaged the power grid and caused electrical blackouts in the Canadian province of Quebec.

"It is extremely rare to get this level of geomagnetic storming," said Larry Combs, space weather forecaster at the National Oceanic and Atmospheric Administration.

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