SPACE WIRE
Second solar eruption stirs up magnetic storm
WASHINGTON (AFP) Oct 31, 2003
The effects of a second powerful solar flare in just three days hit the Earth Thursday, even as the planet was recovering from a similar, earlier geomagnetic storm that snarled telecommunications and sparked a burst of the Northern Lights.

The second eruption was observed Wednesday at 2048 GMT, and the geomagnetic storm it created hit the earth around 1500 GMT Thursday, according to the US National Oceanic and Atmospheric Administration's Space Environment Center.

"It's like the Earth is looking right down the barrel of a giant gun pointed at us by the Sun -- and it's taken two big shots at us," said John Kohl, a solar astrophysicist at the Harvard-Smithsonian Center for Astrophysics.

"The timing of two very large X-class flares aimed directly at the Earth, occurring one right after another, is unprecedented," said Kohl, who is also the principal investigator for the Ultraviolet Coronagraph Spectrometer on board NASA's Solar and Heliospheric Observatory (SOHO) spacecraft.

"I have not seen anything like it in my entire career as a solar physicist. The probability of this happening is so low that it is a statistical anomaly," he added.

The Japanese space agency reported losing communication with one of its satellites, Kodama, on Wednesday at the beginning of the magnetic storm, the biggest in some 30 years.

The storms created some interference with the North American power grid, though utility companies took precautions to minimize power surges.

The X-rays interfered with radio transmissions in certain frequency bands, in particular those used for communication by airplanes travelling at a high altitude close to the Earth's poles, officials said.

Kohl however said the combined effects of both geomagnetic storms could not be predicted.

"This second blast is moving like a fast freight train that very soon will plow into the back of the slower moving freight train in front of it just as it pulls into the station," he said.

"The station, in this case, happens to be the planet Earth."

The first storm erupted from the surface of the sun around 1100 GMT Tuesday, firing a giant cloud of charged ions straight towards the Earth. It was the third most powerful solar eruption ever observed.

The effects of that storm hit the Earth at 1600 GMT Wednesday, just 19 hours after the flare was observed and considerably sooner than scientists had expected.

The solar winds' speed was about five times greater than normal, said Bernhard Fleck, a scientist working with the SOHO spacecraft.

NOAA space weather officials classified the geomagnetic storm as a G-5 or "extreme" on a scale that runs 1 to 5. In terms of frequency, this level of storm occurs only once, if at all, during the 11-year solar activity cycle, officials said.

NOAA reported Wednesday that aurora borealis -- northern lights caused by the charged particles from the Sun -- have been seen in the United States as far south as El Paso, Texas.

As a precaution, the two crew members of the International Space Station have been ordered to spend periods of time sheltered in the Zvezda service module, which offers them higher protection from increased radiation levels.

A solar flare is a magnetic storm on the sun that appears as a very bright spot, and sends gas from the sun's surface into space.

The solar eruption will continue to affect the Earth's magnetic field for the next two weeks, experts say.

The sun's most powerful explosion of flares and gases into space occurred in April 2000, but that burst was directed away from the Earth.

Magnetic storms do not present a danger to personal health because the ionized particles are absorbed or deflected by the Earth's atmosphere.

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