[KarlInOhio]

The article mentions gravitational effects, but doesn't touch the fact that Ganymede is inside Jupiter's magnetic field. Does Ganymede require a liquid core to have a magnetic field, or would it be like rubbing a magnet on a needle to give the needle a magnetic field? Also, could the coupling of Jupiter's magnetic field keep Ganymede's core heated by magnetic coupling rather than the gravitational coupling the article suggests and then dismisses?

[count-your-change]

Another question might be whether the magnetic field poles are close to Ganymede’s rotational poles.

And does Ganymede have sufficient radioactive material to keep the iron core molten?