Today's Forecas

Science  15 Jan 1999:
Vol. 283, Issue 5400, pp. 295a
DOI: 10.1126/science.283.5400.295a

“The apparent void between sun and Earth is actually a maelstrom of wind and storm, with interludes of calm,” reads a blurb on the Space Environment Center's site. Run by the National Oceanic and Atmospheric Administration, this colorful site provides a lively overview of how the sun's fickle outbursts can affect Earth—from lacy auroras to satellite blackouts and radiation risks for astronauts.

The site, which bills itself as “the nation's official source of space weather alerts,” attracts some 500,000 hits per week, says Web master Barbara Poppe. Images of the sun and graphs of x-ray fluxes near Earth are updated minute by minute, giving quick warnings to those who need to safeguard delicate electronic systems. Not surprisingly, satellite operators, navigators, and power companies are among the heaviest users, says Poppe. But teachers also tap into the site's rich tutorials: One can learn, for example, how solar flares and vast blobs of hot gas called coronal mass ejections contort Earth's magnetic field and make space a hazardous place to work.

A similar site run by NASA offers daily probabilities of flares, audio clips of eerie radio “sounds” made by charged particles racing through the upper atmosphere, and movies of the latest sunspot activity. Both sites can expect heavy traffic as the sun nears the peak of its 11-year cycle of activity, expected in early 2001.

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