It's my favourite topic. Magnetism comes from the Aether.
The aether is everywhere at all times. It is pure potential, or energy at rest. Fields are modalities of the aether, just like liquid, ice and steam are modalities of water, mediated through pressure and temperature.
The fundamental modalities of the aether are:
1. Dielectricity
2. Magnetism
3. Electricity
4. 'gravity', which is an effect of electricity, or an antifield.
Dielectricity is the engine of magnetism, where you have magnetism, you will always have the dielectric field powering it. Dielectricity manifests as hyperboloid (hourglass shape) geometry, and magnetism is always toroidal geometry. They are the inverse of eachother, imagine a donut (magnetism) with an hourglass (dielectricity) in the middle of it.
Dielectricity and magnetism coupled with movement through space results in electricity. Magnets accelerate towards eachother because of nature's tendency towards favouring a state of rest, i.e. there is no such thing as magnetic attraction, rather, it is dielectric acceleration towards rest or counterspace.
We have never dug deeper than ~8 miles. There is no molten core or whatever they made up, there is no evidence for the claim and no possible way they could know what's beyond that depth.