Angry sun. Analysis of solar data may help astronomers predict solar flare activity.

Forecasting the Weather ... in Space

Carolyn is a staff writer for Science and is the editor of the In Brief section.

Scientists may soon be able to predict brief "all-clear" periods with no severe space weather on the horizon, giving sensitive satellite systems a breather and astronauts time to spacewalk, a consortium of space weather researchers announced today.

Solar flares are explosions of electromagnetic rays and energetic particles from the Sun. Intense flares can wreak havoc on sensitive space- and ground-based technology and endanger astronauts and sometimes even airplane passengers with harmful radiation. They can release as much energy as 10 million 1-megaton nuclear bombs, most of which is deflected by Earth's magnetic field. Because they travel at the speed of light, getting advanced warning of flares has proven difficult.

That may be about to change, according to researchers from NASA, the National Oceanic and Atmospheric Administration, and the Lockheed Martin Advanced Technology Center's Solar and Astrophysics Laboratory. Analysis of continuous solar data from NASA's TRACE satellite and NASA and the European Space Agency's SOHO satellite has provided a way to give at least a few hours' notice of safe skies, the team says.

Using the satellite datasets, the researchers observed the evolution of the Sun's coronal and underlying magnetic fields over several days. Electrical currents, though not directly visible, could be inferred by comparing model calculations of the Sun's field with actual measured fields. In the presence of those currents, the magnetic field lines became warped and distorted. The team found a high correlation between solar flares and highly warped fields. Using the shape of those magnetic field lines, scientists can predict with 90% accuracy whether a solar flare is likely to occur.

"What we can say is that it's going to be all-clear for a certain period of time," adds Richard Fisher, Director of NASA's Sun-Solar System Connection Division. "That's quite useful for space flight operations and flight planning." Predicting the magnitude of a solar flare is farther in the future, the researchers said. "We have established that there are these electrical currents, but future research is needed to know the magnitude of these currents," said Karel Schrijver, a physicist at Lockheed Martin.

Though current predictions might give astronauts a few hours of clear weather, new research on the Sun's seismology could help extend that forecast to at least a day, Schrijver said.

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