If the earth's core was to abruptly turn solid

[Mr.CROWLER]

How long before our magnetic field disappeared and how long after that would we be dead due to radiation?

 

[mfb]

The core is solid, at least the inner part. If the outer part and the mantle would become solid, there wouldn't be anything keeping a magnetic field up (apart from slight magnetizations of the materials).

Our main shielding against radiation is the atmosphere, and the magnetic field frequently (on geological timescales) reverses its orientation, with phases of very weak fields in between. As you can see, those phases are not dangerous. They might be problematic for power grids and some electronics, but that's something we can handle.

 

[Mr.CROWLER]

Thanks for taking the time to reply, but I'm pretty sure the core is molten.

 

[mfb]

The inner part is solid, the outer part is liquid, I made my post clearer in that aspect.

 

[Hornbein]

How long before our magnetic field disappeared and how long after that would we be dead due to radiation?

I have read that if the Earth ceased to generate its magnetic field it would take 20,000 years for it to disappear completely. I don't know if that is really true, though.

 

[mfb]

What does "ceased to generate" mean then? The magnetic field is nothing that can sustain itself, without a current flow or permanent magnetization is does not exist.

 

[DrStupid]

As the question for the magnetic field is answered we could turn to the thermal effects. How long would it take for the released melting heat to reach the surface?

 

[mfb]

Do you have a scenario where melting heat gets released (so the material gets hotter) and the whole Earth gets solid at the same time?

 

[DrStupid]

Do you have a scenario where melting heat gets released (so the material gets hotter) and the whole Earth gets solid at the same time?

This thread is about a sudden phase transition of the Earth's core. A scenario where the whole Earth gets solid would be another topic.

 

[davenn]

This thread is about a sudden phase transition of the Earth's core. A scenario where the whole Earth gets solid would be another topic.

no, its the point of this topic

the magnetic field won't suddenly/permanently collapse unless the core suddenly/permanently stops rotating and that won't happen unless the outer liquid core suddenly/permanently becomes solid

Its the interaction between the solid inner core and the liquid outer core that generates the magnetic field
its a MHD generatorDave

 

[phinds]

no, its the point of this topic

the magnetic field won't suddenly/permanently collapse unless the core suddenly/permanently stops rotating and that won't happen unless the outer liquid core suddenly/permanently becomes solid

No, you have equated the whole Earth turning solid (which is NOT the topic of this thread) to the inner and outer core turning solid (which IS the topic of this thread). I'm assuming of course that you realize that the inner and outer core do not make up the entire earth. I am agreeing w/ DrStupid and I suspect that you actually agree w/ him as well, but had some misunderstanding about his post.

 

[davenn]

No, you have equated the whole Earth turning solid (which is NOT the topic of this thread) to the inner and outer core turning solid (which IS the topic of this thread). I'm assuming of course that you realize that the inner and outer core do not make up the entire earth. I am agreeing w/ DrStupid and I suspect that you actually agree w/ him as well, but had some misunderstanding about his post.

No I haven't, the rest of the Earth is already basically solid ... its only the outer core that's liquid. Then transitioning into a plastic mantle
If the outer core solidified, then the inner core cannot rotate within it and the generator will stop and the magnetic field will collapse

The don't call it solid Earth geophysics for nothing

Dave

 

[davenn]

... So does anybody know how long we would have our magnetic field after the core becomes completely solid? Would it disappear instantly?

mfb gave you that answer in post #6

 

[phinds]

No I haven't, the rest of the Earth is already basically solid ... its only the outer core that's liquid.

You're right, obviously. I was equating the core turning sold with it being a separate ball inside a thick shell, and moving independently, where as I was equating a "solid earth" as being the whole thing one solid ball. That's why I was seeing it differently.

 

[berkeman]

Thread closed temporarily for Moderation...

Thread re-opened.

 

[DrStupid]

the rest of the Earth is already basically solid

The mantle convections show that the rest is not solid and even if it would be solid now it would melt if the outer core abruptly turns solid. My question is, how long it would take for the resulting superplumes to reach the surface.