It's this dimming signature in the Sun's corona that tells us a magnetic storm is on the way. All of the causes of magnetic storms originate at the Sun, researchers reported at the weeklong conference, co-sponsored by the American Geophysical Union and the National Science Foundation. The particle storms begin when large amounts of coronal mass break away from the Sun and travel rapidly toward Earth. If we can predict that these storms will occur, certainly we will be able to reduce the cost of damage on Earth. New observations at latitudes above and below the Sun's equator point to that possibility.
Magnetic clouds take two to three days to arrive at Earth.
Major disturbances from the Sun erupt about every three to four years, resulting in widespread power blackouts. The most severe in recent years struck in 1989, when an outage in the Quebec province almost shut down the entire northeastern U.S. grid as well, said John Kappenman, an engineer at Minnesota Power. Sometimes the collisions produce auroras, shimmering curtains of light in the northern and southern hemispheres. Other times they create large fluctuating currents that wreck havoc with technologies on the ground. Kappenman said that with a few days advance notice, power and utility companies could mitigate damage by shutting down transformers or redirecting power through alternate grids.