Understanding Earth's Magnetic Field

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<b>Understanding Earth's Magnetic Field</b><br /><br />LINK<br /><br />In an underground bunker that brushes up against a barnyard on one side and a cornfield on the other, scientists from the University of Wisconsin, Madison, are trying to solve an enduring cosmic mystery: how does the Earth generate its magnetic field--the vast, invisible web that shapes the aurora, makes compass needles point north, and shields us from solar storms? And how do similar fields get generated in almost every other planet in our solar system, as well as in the Sun, other stars, and even entire galaxies? <br />Their tool is the Madison Dynamo Experiment, a newly operational laboratory model of the Earth's molten core. Five years in the making, with support provided jointly by the National Science Foundation (NSF) and the Department of Energy, the experiment is the largest of half a dozen such efforts worldwide. And like all the others, says UW physicist Cary Forest, principal investigator on the project, it is designed to fill in some gaping holes in our understanding. <br /><br />Theory has it that magnetic fields tend to arise spontaneously in any rotating, electrically conducting fluid, explains Forest, whether that fluid is the molten iron in the Earth's deep interior or the multi-million-degree plasma at the center of the Sun. But empirical evidence is much harder to come by, given that no one has yet figured out how to stick a probe into the core of the Earth, or into the heart of a star. <br /><br />Thus the gaps. Says Forest, "How fast do the naturally occurring magnetic fields grow? When do they stop growing? What causes them to stop growing? That's the big one. These are really, really fundamental questions that theory doesn't address." <br /><br />And thus the Madison Dynamo Experiment. At its heart is a one-meter-wide, stainless steel sphere that contains about a ton of sodium metal, which ser

 

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More About The Madison Dynamo Experiment

 

[zavvy]

<font color="yellow">I hope we can learn lots from it. </font><br /><br />Me too.. <img src="/images/icons/smile.gif" /><br /><br />I found the PBS programme on the subject of Earth's diminishing magnetic field fascinating. Here's the link for anyone who's interested..