Nova: Magnetic Storm
What is weakening Earthís invisible shield?Magnets have the power to attract and repelósometimes on a massive scale. The Earthís molten coreóa violent mix of searing heat, crushing pressure, and a billion trillion tons of liquid ironócreates an invisible shield that surrounds the globe, guarding against a constant barrage of deadly radiation from space. But over the last few decades, the Earthís magnetic field has weakened dramatically, intriguing scientists across the globe.The power generated 2000 miles beneath our feet protects us every day, but the loss of Earthís magnetic field is a brewing storm that affects us all. While experts research and debate, persistent questions remain. Is a rare geomagnetic reversal the cause of earthís inner turmoil? And if the magnetic field were to vanish altogether, would Earth become as lifeless as Mars? Travel from Hawaiiís molten lava flows to the mountains of Oregon and into the far reaches of outer space for a charged look at Earthís magnetic history and potentially deadly future. Special DVD features include: materials and activities for educators; a link to the NOVA Web site; scene selections; closed captions;  and described video for the visually impaired.     On one DVD5 disc.  Region coding: All regions.  Audio: Dolby stereo.  Screen format: Letterboxed.