What is weakening Earth's invisible shield?

Magnets have the power to attract and repel--sometimes on a massive scale. The Earth's molten core--a violent mix of searing heat, crushing pressure, and a billion trillion tons of liquid iron--creates an invisible shield that surrounds the globe, guarding against a constant barrage of deadly radiation from space. But over the last few decades, the Earth's 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 Earth's 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 earth's inner turmoil? And if the magnetic field were to vanish altogether, would Earth become as lifeless as Mars?

Travel from Hawaii's molten lava flows to the mountains of Oregon and into the far reaches of outer space for a charged look at Earth's magnetic history and potentially deadly future.

Special DVD features include: materials and activities for educators; a link to the NOVA Web site; closed captions; and video descriptions.

On one DVD5 disc. Region coding: All regions. Audio: Dolby stereo. Screen format:Letter boxed.

Series: NOVA
Grade level: Grade 7+
Closed captioned: Yes
60 min on 1 DVD

UPC # 783421 37 0098
ISBN # 1-59375-107-9
2003

Box Size: 7.50in (19.05cm) x 5.25in (13.34cm) x 0.50in (1.27cm)

Recommended for ages 13 and older.

Weight: 0 lb 4 oz ( 0.11 kg )