Previous explanation of the Earths Compass-Active electro-magnetic field appearing in texts books were that the core of the planet is molten Iron that behave like a large Copper coil.
Seriously? magnetizing molten iron would be very difficult because the atoms move around. Regular Iron only becomes a magnet when a magnetic field is being applied. Solid steal can become permanently magnetized because the Iron atoms don't bounce around and are aligned muscularly plus to minus.
In previous posts I discussed Time-Dilation on various sized planets and concluded that the formulae available wouldn't even apply to gas giants like Uranus because it's so massive that the core is neutronic and the planet is heavier than what you would expect from it's radius with the scwartzchild radius being bigger.
The intensity of such planets electro-magnetic fields would likewise be greater than expected.
The causes of intense electro-magnetic fields in planets that are reputed to consist mostly of CH4 NH3 CO2 H20 would make conventional explanations contradictory to their chemical composition.
Who's to say that even with planets like the Earth that there isn't a core within a molten core that is neutronic nuclear thermopile with intense gravitational fields producing an simmering thermopile activity whilst at the same time containing the chain-reacting neutrons to within a precise radius. There would be an imbalance of protons in the core surrounds that would produce the complimentary compass-active electromagnetic field and Earthing effects of Thunder bolts.
This My theory could predict that large-enough distant planets are on the surface warmer than absolute zero in-spite of being to distant to obtain enough sunlight to explain the effect.