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