Frozen earth

[devrimci_kürt]

What would happen to the magnetic field of Earth if the planet suddenly freezes?

[DrP]

I shouldn't think anything would happen to it all. Is there some function equating magnetic field strength to temperature then? I can't remember it if there is one - except that at 'high' temperatures you can loose ferromagnetism (currie point?? ).

 

Also the more I think about it there more I wonder what you mean. Do you mean that the surface freeses (as in zero degrees all over). Or the whole earth, magma and all solidifying to the core? Either way I still think the magnetic field would remain intact.

[Mr Skeptic]

Without the molten core, our magnetic field would be extremely weak and (I think) eventually disappear. However, the surface of the earth, the part you care about, could freeze so cold that the atmosphere is frozen and so long as the core is still molten it would have little effect on the magnetic field.

 

The magnetic field is generated by convection currents of molten metal from the core upward, which due to conservation of angular momentum spin slower than the earth's surface. Since conductor is moving through a magnetic field, this generates an electric current, and the electric current generates the magnetic field. Since the magnetic field is partly caused by the magnetic field, this setup is rather unstable and can (and has) reverse direction.

[NowThatWeKnow]

Wouldn't that be like freezing a beam of light? It may take absolute 0 -1

[scrappy]

What would happen to the magnetic field of Earth if the planet suddenly freezes?

I wouldn’t know why a frozen Earth should affect its magnetic field. There is, of course, the Snowball Earth theory that alleges a entirely frozen planet about 600-700 million years ago. That theoretical episode of freezing and thawing preceded the Cambrian Explosion, which is alleged to have taken place about 550 million years ago. The connection between the two events is speculative, but, if proven correct, a frozen Earth could do a lot more than alter its magnetic polarity. It may have even stressed the biosphere enough to sort out animal body plans and establish durable phylogenies.