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Severe solar storm sparks an alert

By Robert Roy Britt and Jim Banke SPACE.COM

Nov. 9 B A severe space weather storm began pounding Earth late Wednesday and is expected to threaten communications, satellite operations and possibly astronauts and airline passengers B especially pregnant women B through Sunday.

THE EVENT began Wednesday at 6:50 p.m. ET, when a large solar flare welled up from deep within the sun. This energy interacted with the solar atmosphere, sending a stream of charged particles called protons heading toward Earth. BThe protons measured near Earth increased 10,000 times in the matter of a few minutes,B said Joseph Kunches, lead forecaster at the National Oceanic and Atmospheric AdministrationBs Space Environment Center. Forecasters labeled the event an S4. The most severe would be an S5. The event was different from other recent solar storms B less likely to generate an increase in the northern lights, forecasters said. But at the same time itBs potentially more dangerous to humans. The protons buffeting Earth are a form of radiation that, with extended exposure, is thought to damage DNA and contribute to cancer. While cosmic radiation from distant sources constantly bombards Earth, the amount increases during a severe solar storm. People on the ground are not at risk, as EarthBs magnetic field and atmosphere provide a blanket of protection. NOAA says an airline passenger could experience as much radiation as 10 chest X-rays, though this figure is debated. Experts do agree, however, that anyone on a high-altitude jet or in space is exposed to more radiation than someone on the ground. MOST NEEDNBT CHANGE PLANS Wallace Friedberg, who studies the threat for the Federal Aviation Administration, said that the NOAA estimates are the best available. He said most people planning a flight during the storm should not necessarily change their plans, adding that the radiation measurements he has seen indicate that this event is not the worst possible. BIf it was my daughter, and if she was pregnant, IBd tell her she might want to wait,B said Friedberg, who heads the radiobiology research team at the FAA Civil Aeromedical Institute. BIf sheBs not pregnant, I wouldnBt be that concerned.B Friedberg has a short flight scheduled himself this weekend. BIf I was going today, I would go,B he said. BBut IBm not pregnant.B Advertisement

High-frequency radio communications will also be strongly affected through Sunday, when the proton stream is expected to die down. The proton stream would be strong enough to be dangerous to astronauts if they are on spacewalks. There are three people B one American and two Russians, living aboard the international Space Station Alpha. BNASA is acutely aware of the fact that there is some hazard to them based on the radiation environment,B said NOAABs Kunches. BAnd today is one of those days that they need to worry.B NASA says the three crew members aboard Alpha are in no danger from the event. However, flight controllers near Moscow have asked station commander Bill Shepherd and cosmonauts Yuri Gidzenko and Sergei Krikalev to set up a radiation-monitoring device inside the Russian-built modules as a precaution. The portable device, similar to those used during each space shuttle mission, will sound an alarm if it senses radiation that reaches a preset level, said NASA spokesman Rob Navias. If that should happen, the three crew members will move to the end of the Zvezda service module, where the Soyuz spacecraft is docked, and remain there until the radiation level subsides. This part of Space Station Alpha offers the most protection from the hazard, Navias said. In any case there is no need for Shepherd, Gidzenko and Krikalev to move into the Soyuz for protection, nor are there any plans for the crew to evacuate the station and return to Earth.

-- Rachel Gibson (, November 10, 2000

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