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Name: Sashank
Status: student
Grade: 9-12
Country: India
Date: Spring 2013

Often, the answer about Earth's magnetism is that it is due to the moving iron core. But Earth's moving core is more than 6000 degrees Celsius. How can it behave as a magnet at that 'Very High' temperature (higher than the Curie Point) where even Iron melts?

Hi Sashank,

You are correct that Earth's core exceeds the Curie temperature of its component materials. The cause of Earth's magnetic field is the dynamo action of charged particles in the outer, fluid core of the planet.

Deborah Glosser Geology and Planetary Science

Above the Curie temperature, a permanent magnet changes to a paramagnet (meaning it loses its intrinsic magnetic field, but still can have an induced magnetic field). For the Earth, the magnetic field is not due to intrinsic magnetism of its solid iron core, it is due to an induced magnetic field owing to convection of the liquid iron shell around the solid core. Thus, the liquid shell of iron is the source -- not a barrier -- to the magnet field.

Hope this helps, Burr Zimmerman

Earth?s magnetic field is not well understood. It appears to be created by electric currents in the conductive metallic core. So in essence it is an electromagnet, not an iron ferromagnet.

Richard E. Barrans Jr., Ph.D., M.Ed. Department of Physics and Astronomy University of Wyoming

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