Sunspots Can Now Be Predicted Days in Advance
Sunspots are regions on the sun's surface that are cooler than the surrounding areas and so appear darker. (See sunspot pictures: "Sharpest View Yet in Visible Light." ) The spots form due to intense magnetic activity, and other magnetically driven solar events—such as flares and coronal mass ejections (CMEs)—tend to erupt from areas where sunspots appear. When solar flares and CMEs are aimed at Earth, they send clouds of charged particles from the sun racing toward our planet. As these particles interact with our magnetic field, they create geomagnetic storms that can pose hazards to astronauts and spacecraft in orbit as well as to power grids and telecommunications equipment on the ground. (See "As Sun Storms Ramp Up, Electric Grid Braces for Impact.") Knowing when and where sunspots—and any associated flares and CMEs—will form may therefore be key to predicting solar storms. "With our technique, we can detect sunspot regions 60,000 kilom...