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Building a Miniature Magnetic Earth

Posted by CmdrTaco on from the don't-bring-your-laptop-near-there dept.

Doofus writes "There was an interesting story on NPR this morning about a geophysicist who has constructed a miniature earth to model the earth's dynamo 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. The article includes both video, in which Lathrop spins up the sphere, and audio, including the conversion of magnetic wave functions in prior experiments into audible sound: literally the music of the spheres."

5 of 150 comments (clear)

  1. any chance by Trailer+Trash · · Score: 4, Interesting

    we can throw it in a lake when he's finished? That's a *lot* of sodium.

    --
    Do you have ESP?
  2. Re:thats a lot of sodium... by hkfczrqj · · Score: 4, Interesting

    Just FYI, one of the technicians working in this experiment used to work in a nuclear submarine, I presume taking care of the cooling of a reactor. I don't know what kind of reactors they use in the Navy, but Dr. Lathrop told me that this guy knows how to handle liquid sodium. (Disclaimer: I'm in a collaboration with Lathrop's lab, though in another experiment.)

  3. Why sodium? by Fallen+Andy · · Score: 3, Interesting
    Anyone out there can explain to me why he wouldn't use e.g. Gallium ? Sodium sure isn't the safest stuff to have around molten.

    Andy

  4. Re:solid core? by DerekLyons · · Score: 4, Interesting

    Don't you need the solid iron core, so that you have the 2 iron pieces separated by the liquid (sodium) mantle ?

    Not to study the gross effects of turbulent conductive metal. Simple experiments first, complex experiments later.
  5. Re:Major flaw in design... by n3umh · · Score: 3, Interesting

    "I'm no geophysicist, but I have a hunch gravity has a huge impact on the equation when it comes to the generation of the Earth's magnetic field."

    Only in that the earth's core's flow is driven by convection (both/either thermal and compositional)

    The static pressure field in a fluid cancels out gravitational effects, so in our experiment (I'm one of the graduate students who's been building the thing) there's just a slight increase in pressure as you go deeper in the sodium that doesn't change its electrical or hydrodynamic properties at all.

    In the earth, buoyancy forces are important to stir up the core. In our experiment, we use differential rotation between a pair of spheres to drive the flow. That aspect is not particularly earthlike, but easier to put a lot of energy in.