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Saturday, October 25, 2003



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NASA SOHO SATELLITE PHOTO VIA ASSOCIATED PRESS
A geomagnetic storm spawned by a giant eruption of gas on the sun barreled toward Earth yesterday at 2 million mph.


Geomagnetic storm
hurtling toward Earth

UH solar astronomers are baffled
by unusual activity on the sun


University of Hawaii solar astronomers are observing unusual activity on the sun such as two giant spots, explosive flares and a strong geomagnetic storm.

"It's out of phase; the sun is not doing what we expected it to do," said Jeffrey Kuhn, associate director of the Institute for Astronomy's solar program on Haleakala, Maui.

University of Hawaii He said two major sunspots are covering almost one-third of 1 percent of the sun, which is 10 times more than expected for this time of the year. The area covered by the sunspots also appears to be increasing, he said.

This is unexpected because the sun's 11-year cycle of activity -- the solar maximum -- is in a declining phase, Kuhn noted. It peaked around 2000 and is headed for minimum activity roughly in 2005, he said, "so it's quite unusual that the activity should be like what it is in the solar maximum."

Solar astronomer Don Mickey said a cluster of sunspots appeared earlier this week "without anybody really expecting it to show up.

"A week ago," he said, "nothing was there."

The two groups are called 484, near the center of the sun, and 486, to the southeast.

Mickey said the largest single spot in group 484 is larger than Earth, and the cluster covers an area about four times Earth's diameter.

During the past two days, it covered 0.17 percent of the visible disk, he said.

"It doesn't sound like much but it is huge."

SpaceWeather.com said astronomers cannot remember the last time two "Jupiter-sized" sunspots crossed the sun's face at the same time.

The spots are large enough to see with the unaided eye, but it is not safe to look directly at the sun, the astronomers warned. Viewers should use smoked or welder's glass or a Mylar filter if the sun is low on the horizon.

Mickey said the 484 group is complex because the sunspots have opposite (north and south) polarities close to each other, and they are "almost intermixed."

"When you get a complex configuration like that, where magnetic fields are mixed up and spots are moving around and rubbing on each other, is when you expect larger solar flares."

A typical solar flare, the largest explosion in the solar system, can release energy equivalent to millions of 100-megaton hydrogen bombs.

The flares can disrupt or wipe out electronic and satellite communications, affecting radio signals, portable phones and pagers.

Four major flares occurred in 24 hours, which was the kind of activity seen during the peak in 1999 and 2000, he said.

The result is "lots and lots of space weather," such as geomagnetic storms, Kuhn said.

A giant eruption of gas on the sun triggered a geomagnetic storm directed at Earth yesterday.

High-frequency airline and radio communications for teams on Mount Everest were affected, but no major problems occurred, federal officials said.

The storm, a "coronal mass ejection," whirled toward Earth at 2 million mph, officials said. It was expected to be the strongest yesterday, but the warning extended until today, Kuhn said.

Another coronal mass ejection was predicted to reach Earth last night or today and cause a new round of storms.

Kuhn said the storm can be detected by holding a compass.

"A very sensitive needle would wobble. It wouldn't point directly at the north because of magnetic energy from the sun interacting with the earth's magnetic field and causing it to wave."

UH astronomers are monitoring the solar activity from the Mees Solar Observatory on Haleakala.

"It's surprising to see this quite as active as it is; it's not something we understand," Kuhn said. "This is one of the research areas to try to understand why the sun is variable the way it is."

"It's kind of like a snowstorm in June in Colorado," said Larry Combs, space weather forecaster with the National Oceanic and Atmospheric Administration's Space Environment Center in Boulder.

Power companies were notified and taking precautions to avoid voltage problems and blackouts, Combs said.

Satellites are at risk but built to withstand such events, he said. If problems occur, satellites can be put into a "stow position" until the storm passes, he said.

Cell phones are not likely to be affected unless they depend upon satellites, Combs said.

Residents of Arizona, Wisconsin and other areas have reported seeing northern lights sparked by the magnetic storm.


The Associated Press contributed to this report.


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