WASHINGTON,
Nov 25 (AFP) - Across the United States this weekend, fire alarms
and anti-theft devices may be triggered for no reason, pictures
on television screens may flicker and fade to black, and entire
communities could be plunged into sudden darkness.
Such unusual
goings-on things could result from what scientists describe as
a wave of major geomagnetic storms expected to strike beginning
late Saturday and last for several days.
In an alert
issued Friday, the US government's Space Environment Center said
"a major solar flare from a large, active sunspot group"
was observed on the Sun from Boulder, Colorado, last Thursday,
at 8:13 am local time (1513 GMT), likely producing "additional
major events."
The solar
radiation storms and strong geomagnetic storms categorized by
the center as "G3", officials said.
Under such
storms "power system voltage corrections may be required,
false alarms triggered on some protection devices, surface charging
may occur on satellite components, drag may increase on low-Earth-orbit
satellites, and corrections may be needed for orientation problems,"
the center pointed out.
The list of possible calamities doesn't end there, however.
The storm
wave could cause interruptions in navigation satellite communications
and become a real headache for high-frequency ham radio operators,
according to the center.
"In the
worst case scenario, power can be lost," Norman Cohen, a
space environment forecaster with the National Oceanic and Atmospheric
Administration, told AFP.
He said failures
of power grids were more likely to occur "at higher latitudes
in both hemispheres," but the geomagnetic storms -- to continue
for at least several days -- would affect the whole planet.
"It will
be global event. And we won't know the magnitude until it actually
starts," Cohen stressed.
He said the flare observed on the surface of the Sun on Thursday
has spawned a large cloud of plasma, which is heading towards
the Earth.
"From
its appearance, we have been able to determine that it was Earth-directed,"
Cohen explained. "It will be a major event."
The magnitude
of the storms was expected to reach six or seven on a scale of
nine, according to the forecaster.
As a result,
orbiting satellites may experience "some orientation problems"
and "will need correction from ground control," Cohen
said.
That may affect
some communications, but television networks and cellular phones
should be working normally, said the forecaster. If interruptions
were to occur, they should be brief.
Power grids,
however, may be worst-equipped to withstand the geomagnetic onslaught
from space.
In 1989, most of the power grid in the Canadian province of Quebec
went down for an expended period of time due to such a storm,
Cohen reminded.
On the bright
side, night-time skywatchers in areas far beyond the Arctic could
be treated to a spectacle they have never seen before.
Aurora Borealis,
otherwise known as Northern Lights, could be seen in North America
as far south as the US states of Oregon and Illinois, the center
said.
"Most
of Europe will be able to see it too," added Cohen.
He said in
Illinois and Oregon, the aurora will probably be visible starting
at around midnight Saturday. In Europe, it is most likely to be
detected on Sunday and following days after dark.
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