This “Three Meter Geodynamo” project conducted at the University of Maryland was built to study how planets generate magnetic fields. The rotating sphere attempts to generate a magnetic field from spinning liquid sodium metal. Very impressive project and be sure to check out the construction details at the link below.
12 thoughts on “Spinning sphere emulates planet’s magnetic fields”
Sodium is easy to melt, but unlike planet cores it is not ferromagnetic (the cores of telluric planets are thought to be made primarily of iron and nickel). Isn’t it an essential property regarding how they generate magnetic fields ?
As far as we know, the molten iron core of the earth is not ferromagnetic. It’s too hot; very probably above the Curie temperature.
It’s possible that there’s an exotic state of iron or nickel that’s ferromagnetic at those pressures and temperatures, but as far as I know, it’s thought that the Earth’s core is merely an electrical conductor.
The better the electrical conductivity, the easier it is to get a magnetic field for a given size and input power, so we use Sodium, which is the best electrically conducting fluid out there.
It’s also cheap and doesn’t weigh much compared to other liquid metals.
Then somebody sneezes into the sodium and blows up the entire state of Maryland.
Did you get Jodie Foster to ride in it, trying to get to Vega?
Not yet ;-)
I didn’t think about the Curie point. Thanks for the answer :-)
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