"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 degrees geomagnetic lat.).

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

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.

For more information, contact:

David Aguilar
617-495-7462
daguilar@cfa.harvard.edu

Christine Lafon
617-495-7463
clafon@cfa.harvard.edu