Giant Solar Eruption Predicted To Cause Major Geomagnetic Storm

http://cfa-www.harvard.edu/press/pr0322.html

Harvard-Smithsonian Center for Astrophysics
Release No.: 03-22
For Release: 12:20 p.m. EST, October 28, 2003

Wildfires On The Sun: Giant Solar Eruption Predicted To Cause Major
Geomagnetic Storm

Cambridge, MA--At approximately 5:54 a.m. EST this morning, a gigantic
solar flare erupted from sunspot 10486 on the surface of the Sun. That
explosion blasted tremendous amounts of energy and matter into space,
sending a coronal mass ejection (CME) directly toward the Earth. That CME
is predicted to create a major geomagnetic storm when it reaches our
planet on Thursday.

"This is the real thing," says John Kohl, a solar astrophysicist at the
Harvard-Smithsonian Center for Astrophysics (CfA) and principal
investigator for the Ultraviolet Coronagraph Spectrometer on board NASA's
Solar and Heliospheric Observatory (SOHO) spacecraft. "The eruption was
positioned perfectly. It's headed straight for us like a freight train, so
a major geomagnetic storm is bound to happen when it reaches us on October
29th or 30th."

"Last week's CME hit the Earth with only a glancing blow," says Kohl,
although it was sufficient to disrupt airline communications. "Today's
eruption was pointed directly at us, and is expected to have major
effects."

"This is the strongest flare we've seen in the past 30 years," says Leon
Golub, CfA astrophysicist and author of "Nearest Star: The Surprising
Science Of Our Sun." Today's solar flare was classified as an X18-category
explosion, meaning that it can trigger planet-wide radio blackouts and
long-lasting radiation storms.

"We are waiting for the prediction of the geomagnetic storm level from
NOAA (the National Oceanic and Atmospheric Administration)," says Kohl.
"What we know at this point is that the flare was nearly perfectly
positioned near the center of the Sun, and that a halo coronal mass
ejection has left the Sun and is heading toward the Earth. The geomagnetic
storm is likely to be a strong one, and will last about 24 hours."

NOAA classifies geomagnetic storms on a scale from 1 to 5. Initial
indications show that this has the potential to be a G5 storm - the top of
the scale. The most benign effect of such a storm would be bright auroras
visible from more southern latitudes than usual. However, the geomagnetic
storm triggered by the CME also could interfere with satellite
communications; disrupt power grids (as occurred in the 1989 Quebec
blackout); even short out orbiting satellites, rendering them permanently
inoperable.

"We've already had to shut down our SOHO instrument for safety reasons.
It's getting blasted by high-energy particles from this solar flare," says
Kohl. "Of more concern, geosynchronous communications satellites are
likely to be affected." In California, where raging wildfires have damaged
many microwave communication antennas on the ground, satellite
communications have been crucial to emergency efforts. Emergency personnel
should be prepared for potential disruptions and communication
interference.

"There's no direct danger to people on the ground," Kohl adds, "and I'm
sure that NASA is monitoring the situation for any potential effects on
the space station crew, and that they are taking appropriate precautions."

According to NOAA, a G5-class geomagnetic storm can have the following
effects:

* Power systems: Widespread voltage control problems and protective
system problems can occur, some grid systems may experience complete
collapse or blackouts. Transformers may experience damage.
* Spacecraft operations: May experience extensive surface charging,
problems with orientation, uplink/downlink and tracking satellites.
* Other systems: Pipeline currents can reach hundreds of amps, HF (high
frequency) radio propagation may be impossible in many areas for one
to two days, satellite navigation may be degraded for days,
low-frequency radio navigation can be out for hours, and aurora has
been seen as low as Florida and southern Texas (typically 40°
geomagnetic lat.).

Solar astronomers say to stay tuned. This eruption is coming our way!

Images and animation associated with this release are available at:
http://cfa-www.harvard.edu/press/pr0322image.html

Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center for
Astrophysics is a joint collaboration between the Smithsonian
Astrophysical Observatory and the Harvard College Observatory. CfA
scientists, organized into six research divisions, study the origin,
evolution and ultimate fate of the universe.

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