December 2001

Here Comes the Sun

Space

By Kevin Hogan

You might be worried about blizzards this winter, but what about coronal mass ejections? These giant blasts of electrified particles from the sun, along with solar winds and other space weather, frequently cause disturbances on earth, disrupting radio communications and inducing surges in power lines. But space weather forecasters could soon predict such events with better precision, thanks to a new imaging tool in use by the National Oceanic and Atmospheric Administration.

Strapped to a weather satellite, the new technology can detect solar flares, geomagnetic storms and other space weather events with far greater accuracy than present ground-based systems. The instrument consists of a telescope that captures x-rays emanating from the sun and a detector that converts the x-rays to visible light so images can be beamed to ground stations for analysis. Forecasters then get out the word via e-mail, fax and phone that, for example, a cloud of electrically charged gas is on its way to earth-a journey that can take anywhere from minutes to 36 hours. The alert can detail both where and when the space weather will arrive.

"We'll certainly see some things we haven't seen before," says Chris Balch of the Space Environment Center in Boulder, CO. That could help forecasters warn electric companies, say, that a surge was about to hit their power lines, in time for them to decrease output so the lines wouldn't be overloaded. NASA might even decide to change spacecraft orbits when a blast of radiation is predicted-helping astronauts stay safe from space storms.