Predicting Space Weather Becomes More Precise

Predicting space weather is getting more precise. Twice in the past week, forecasters have warned us about two solar storms with the potential for creating havoc among Earth's electrical systems and orbiting satellites. The world is much better prepared to deal with ferocious solar activity than it used to be. At one time, scientists thought the space between Earth and Sun was a vacuum. But we now know that the sun fills it with gusts of hot, electrically charged atomic particles called the solar wind. Sometimes this wind blows very hard, as it has with the two most recent solar flares. When the sun's outer layer, the corona, is very active, it hurls nearly one-third of its gaseous matter outward at supersonic speeds. A heavy blast can produce a shock wave that compresses our planet's magnetic field. The U.S. government's oceans and atmosphere agency NOAA has a Space Environment Center that monitors these discharges. Center director Ernest Hildner says intense solar emissions are not dangerous to people on the ground, but can shut down satellites, power networks, communications, and other technical systems. The intensity of these solar blasts varies over an 11-year cycle as the sun's magnetic field grows stronger, then weaker. The peak of the most recent 11-year solar cycle came in 2000, but is still a few years from the bottom.