Spot the sun's next attack

摘要

JUST before noon on 1 September 1859, an English solar astronomer named Richard Carrington witnessed the biggest solar flare ever recorded. About 18 hours later, an intense magnetic storm hit Earth. Currents induced in telegraph wires in Europe and North America sparked fires. If the 1859 event were to occur today, it could devastate our modern technological infrastructure. So researchers are now turning to automated image-processing and artificial intelligence to better forecast the sun's behaviour and give us time to prepare for a solar onslaught. Over the past two decades, several solar flares and magnetic storms of varying intensity have hit Earth. Solar flares are surges of X-rays, gamma rays and extreme ultraviolet radiation, and they can damage electric grids, fry satellite electronics and endanger astronauts in space. Even passengers and pilots on aircraft flying over the poles are at risk. Coronal mass ejections (CMEs), which cause magnetic storms, can strike even closer to home (see "Shock wave blackout", below).