Magnetic-Shield Cracks Found; Big Solar Storms Expected
Victoria Jaggard in San Francisco
National Geographic News
December 17, 2008
An unexpected, thick layer of solar particles inside Earth's magnetic field suggests there are huge breaches in our planet's solar defenses, scientists said.

These breaches indicate that during the next period of high solar activity, due to start in 2012, Earth will experience some of the worst solar storms seen in decades.


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Earth's Atmosphere: Facts, Photos, More
Solar winds—charged particles from the sun—help create auroras, the brightly colored lights that sometimes appear above the Earth's poles.

But the winds also trigger storms that can interfere with satellites' power sources, endanger spacewalkers, and even knock out power grids on Earth.

"The sequence we're expecting … is just right to put particles in and energize them to create the biggest geomagnetic storms, the brightest auroras, the biggest disturbances in Earth's radiation belts," said David Sibeck, a space-weather expert at NASA's Goddard Space Flight Center in Maryland.

"So if all of this is true, it should be that we're in for a tough time in the next 11 years."

(Into the Breach

Data from NASA's THEMIS satellite showed that a 4,000-mile-thick (6,437-kilometer-thick) layer of solar particles has gathered and is rapidly growing within the outermost part of the magnetosphere, a protective bubble created by Earth's magnetic field.

Normally the magnetosphere blocks most of the solar wind, flowing outward from the sun at about a million miles (1.6 million kilometers) an hour.

"The solar wind is constantly changing, and the Earth's magnetic field is buffeted like a wind sock in gale-force winds, fluttering back and forth in response to the solar wind," Sibeck said this week during a meeting of the American Geophysical Union in San Francisco.