November 10, 2003

NOVA program features UCSC Earth scientists

By Tim Stephens

Two UCSC researchers are featured in an upcoming NOVA television program about the Earth's magnetic field. Gary Glatzmaier and Robert Coe, both professors of Earth sciences, provided their expertise on and off camera for the program "Magnetic Storm," which airs on PBS stations on November 18 at 8 p.m.

The program's "hook" is the idea that the Earth's magnetic field, which protects the planet from harmful solar radiation, is weakening and may be starting to undergo a dramatic reversal, when the north and south magnetic poles would trade places. This happens on average every 250,000 years, but it has been more than 700,000 years since the last reversal.

In the program, Glatzmaier explains the workings of the "geodynamo," the flow of molten iron in the Earth's core that generates the magnetic field.

Glatzmaier and his collaborators have been able to simulate the behavior of the geodynamo using powerful computers. A movie of Glatzmaier's computer simulation is featured on the program's companion web site.

Coe took the program's producers into the field to show them the geologic evidence of magnetic field reversals in Earth's distant past.

Rocks that formed at different times have preserved a record of how the magnetic field has varied over geologic time. Coe uses this paleomagnetic record to investigate the movement of tectonic plates as well as the behavior of the geodynamo.

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