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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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