Eli5 The earth has a magnetic field, including because of the metal core, but magnets are demagnetized at high temperature. How is this possible
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Oh this is a super cool question! You are indeed correct, bar magnets and those like it can not do hot temps, they fail. But that’s not how the Earth’s magnetic sphere operates. Here on the surface we often use stable magnets to generate electricity. This works on a principle that moving magnetic fields through each other creates electric current. But this is also true in reverse. Moving electric fields can cause magnetic fields.
So the Earth’s core is iron nickle… stuff, we’re not 100% but it’s metal and it’s solid and it’s hot AF. This basically only operates as an antenna. The outer core, however, is liquid and it moves, a lot, moving differently charged metals next to each other causes electricity to generate. And a side effect of generating electrical charge is you also create magnetic fields. This is then focused to the poles because of the axis of rotation and the rotation itself. The sciency name for this is called the “Dynamo Effect” which sounds like a stupid made up sci-fi hand wave, but that’s the name, they didn’t consult me when they named it.
But that’s the gist. The earth is basically accidentally a magnet, it’s a side effect of a geological process of having a liquid metal outer core that’s just hot enough and under just enough pressure for this to work.
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