Charlotte Observer
Posted at 4:57 p.m. EST Thursday, March 29, 2001
Sunspot could disrupt weekend
communications
By SETH BORENSTEIN KNIGHT RIDDER NEWSPAPERS
WASHINGTON -- The biggest sunspot in a decade could disrupt satellite
communication and power grids this weekend, but if the weather is clear
northern U.S. communities also will enjoy a spectacular northern lights
display.
The huge dark spot on the sun's surface -- 13 times Earth's diameter -- is
caused by a surge in magnetic activity this week in the sun's atmosphere. A
storm of magnetic particles from the surge is due to reach Earth this
weekend.
Satellites orbiting Earth will be the first things affected. Some are likely to
shut off, as they would in response to a surge in electrical power. That
could disrupt communications, including network television broadcasts that
involve satellites.
Next to be hit will be power plants, transformers and power lines. They,
too, will respond as if to a power surge, and may shut down. That
happened in Quebec in 1989 during a powerful magnetic storm.
Since then, power companies have responded by reducing power slightly
before a magnetic storm to absorb surges. Still, it might be a good weekend
to hit the computer's save button more often and be sure it's turned off
when not in use.
Norman Cohen, a space weather forecaster at the federal Space
Environment Center in Boulder, Colo., said in a telephone interview that he
expects "a medium grade storm" Friday, Saturday and Sunday.
The northern lights, or aurora borealis, a colorful sparkling event usually
seen only in Alaska and northern Canada, will move further south as a
consequence. Weather permitting, people in Michigan, Minnesota, North
Dakota, Wisconsin, Washington state, Idaho, Montana, New York and
New England may get a good view this weekend, Cohen said.
The storms could continue into next week because the part of the sun
where the spot is -- just a bit above and to the right of the center --doesn't
turn away from Earth until April 5, Cohen said.
The sunspot is so large that if someone had proper eye protection -- such
as specially made glasses approved for use during a solar eclipse -- it could
be seen with the naked eye. But don't try it without such protection, Cohen
advised.
(e-mail: sborenstein@krwashington.com)
For more information, check out the following Web sites:
The Space Environment Center: www.sec.noaa.god
SpaceWeather.com: www.spaceweather.com
03-29-01
fg-jw-ba
AP-DATAPORT-NY-03-29-01 1625EST
-- Anonymous, March 30, 2001
BBC - Friday, 30 March, 2001, 14:04 GMT 15:04 UK
Giant sunspot erupts
Noaa 9393: Fourteen Earths would fit inside the group
Art Whipple
By BBC News Online science editor Dr
David Whitehouse
Two major flares have erupted on the surface
of the Sun in the region of the giant sunspot
group designated Noaa 9393.
The group is the
biggest seen on the
surface of our star for
more than a decade.
One of the flares
(explosions in the Sun's
atmosphere) was so
energetic that it
ejected a cloud of
superhot gas into
space.
Solar observers say
that the cloud, called a
coronal mass ejection
(CME), is heading towards the Earth and will
reach us within the next 24 to 36 hours.
Scientists are predicting a "geomagnetic storm"
when it reaches us. There may be radio and
communications interference, and possibly a
fine display of the Northern, and Southern,
Lights, visible from lower latitudes than is
usually possible.
Very excited
Geoff Elston, director of the solar section of
the British Astronomical Association (BAA), has
been studying the monster sunspot, Noaa
9393, for several days.
"It is definitely the
largest we have seen
for a long time,
probably for many
decades," he told BBC
News Online. "It has
overtaken the size of
the most recent large
one that occurred in
March 1989."
Elston said observers
did not think the spot
would get any bigger.
"Over the past day or so, it has shrunk a little
and this trend is likely to continue. It's
probably past its best."
Noaa 9393 has provided astronomers with an
insight into the complicated way magnetic
fields behave on the Sun's surface.
Record holder
Researchers were able to observe the dynamic
interface between two regions of the sunspot
that had opposite polarity.
It was along the dividing line between the
spot's north-pole and south-pole regions that
the flare took place. Magnetic energy was
released along the interface and turned into
heat. This caused the explosion and the CME.
Although very large by normal standards, Noaa
9393 is way short of the all-time record holder.
That title is held by a spot group which
appeared in 1947. It was three times larger
than Noaa 9393.
Sunspots are magnetic regions on the Sun's
surface. More of them appear on the Sun
during the time of solar maximum, which
happens every 11 years. Astronomers believe
that 2000-1 is the time of the current
maximum.
-- Anonymous, March 30, 2001
