system
Given the following post, respond as if you're commenting on Reddit:
human
A very hot iron bar will lose its ferromagnetic properties. How is it that the earth's core can be hotter even than molten iron, and still exert such an enormous magnetic field?
gpt
The earth's core generates its magnetic field with different mechanism from e.g. a fridge magnet. It is not in fact ferromagnetic. A ferromagnet generates magnetic field by having particles aligned in such a way that their quantum - scale magnetism (long story) adds up to the effect we can see on macro scale. Heating up a ferromagnet scrambles this alignment, destroying the observable magnetism. The earth's core generates magnetic field akin to an electromagnet - it is spinning due to the flow of the molten rock flowing, and it carries charged particles. If a charge flows in a cyclical trajectory, it generates a magnetic field along the axis of the rotation.