If you heat up a magnet it stops being a magnet. So why is the molten metal in the earths core a magnet if it’s so hot?Also if you had a pure iron asteroid that was going to miss the earth but go really close nearby would the magnetic field have any pull on it not caused by gravity?
In: Planetary Science
A solid permanent magnet basically comes from the iron (or other magnetic material) basically being lined up in a particular direction. Since when it melts, this is no longer the case, it isn’t a magnet anymore. In the Earth, the core is partly molten, and is spinning. The spinning iron causes a dynamo effect, which is what causes the magnetic field.
As for the asteroid, yes it could be affected, but the effect would be extremely tiny. The magnetic field is not particularly strong, and the strength drops off quickly the farther away you are. Something like a compass needle is affected only when there’s very little friction and if it has very little inertia (aka mass). Your heavy asteroid won’t be affected much at all
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