Dynamo-hum: Building a miniature earth
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Doofus
Doofus writes "An interesting story on NPR this morning, about a geophysicist who has constructed a miniature earth to model the earth's dyanmo effects.
Dan Lathrop, a geophysicist at the University of Maryland, has constructed a 10-foot diameter stainless steel sphere. He intends to fill the sphere with molten sodium, and spin the sphere to examine the propensity for the system to generate its own magnetic field.
Dan Lathrop, a geophysicist at the University of Maryland, has constructed a 10-foot diameter stainless steel sphere. He intends to fill the sphere with molten sodium, and spin the sphere to examine the propensity for the system to generate its own magnetic field.
The article includes both video, in which Lathrop spins the sphere up, and audio, including the conversion of magnetic wave functions in prior experiments into audible sound: literally the music of the spheres."Scientists believe the Earth's field comes from molten metal churning deep inside its core. If you could dig a deep hole, about 2,000 miles down, you would hit the outer core, which is probably made of liquid iron. That iron can conduct electricity. And if it flows in the right way, it can turn the Earth into what scientists call a dynamo, generating a self-sustaining magnetic field — in Earth's case, producing one pole up in Canada and another down in Antarctica.
Iron only melts at high temperatures, though, so Lathrop's team will fill his sphere with a different metal — sodium. Sodium becomes liquid at stovetop temperatures and conducts electricity well, but it's flammable. A sodium fire can't just be put out with water. Water can actually make things worse — Lathrop's team has disabled the sprinkler system.
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Dynamo-hum: Building a miniature earth