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I am trying to construct a terrestrial planet that is almost entirely made of silicates but with a core that's able to generate a magnetic field. I really don't want to use iron, nickel, or cobalt, and was wondering if I could use a non-ferromagnetic metal. I was thinking maybe titanium (aparently its weakly magnetic🤔). Would this be possible? Or would the magnetic field be too weak? I know that Jupiter has a field from metallic hydrogen so I don't know what is and isnt possible at this point.

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  • $\begingroup$ I don't think it’s possible. If you have particular aversions to iron, nickel and cobalt, how about gadolinium or dysprosium? Both are ferromagnetic. $\endgroup$ – Slarty Oct 19 at 20:45
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    $\begingroup$ Iron is not ferromagnetic in the conditions prevalent at the Earth's core, so the answer is trivial: yes, it is possible, because we have the example of Earth, which has a magnetic field and its magnetic field is not generated by ferromagnetic materials. (Hint: the Curie temperature of iron is about 800 degrees Celsius.) $\endgroup$ – AlexP Oct 20 at 3:19
  • $\begingroup$ Where in that star system did the heavier elements go? $\endgroup$ – RonJohn Oct 20 at 20:34
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Yes. The fact that the Earth's core is made of materials that are ferromagnetic at standard temperature and pressure is completely coincidental--it has no bearing on the generation of the geomagnetic field. In the regions where the field is generated, iron and nickel are in fact not ferromagnetic.

All that's necessary is that you have an electrically conductive fluid. Experimental simulations of the geodynamo make use of rotating spheres of molten sodium. Molten titanium should work just fine.

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To generate a planetary magnetic field you just need a liquid metal where electrons can float freely.

There are several options for this, these are a few examples which come to mind:

  • Iron and Nickel

This is the Earth setup, but I thought I'd mention it. Wikipedia explains pretty well how it is generated.

  • Metallic Hydrogen

This is the Jovian setup and shows that one doesn't even need a true metal.

  • Magnesium Oxide

Some recent reasearch suggests that magnesium oxide turns into a conductive liquid at pressures one might expect in super-earths. This is the most realistic bet in my opinion.

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