Earth's magnetic field collapsing!

[CerberusIV]

Originally posted by Ned
But, Mr. where it's at, since the Earth's core rotates only in one direction, why does the magnetic field flip if it is the rotation of the electrons that cause the field.

Not that simple. There are convection cells in the liquid core so material moves between different depths and the overall field is the result of many different fields from the different movements in the core.

[Ned]

CyberusIV, wouldn't the core also rotate the same as our atmosphere - with the flow nearer the poles being opposite that near the equator?

[-Jrabbit]

Originally posted by MWIA
Some solid Earth scientists are starting to believe in just such a dual-layer outer core model, but again, this is all just guesswork with computer simulations thrown in.

All I know is, that dual-layer outer core model produces one helluva golf ball!
God bless those solid Earth scientists! Fore!!

[Sarxis]

Originally posted by Ned


Actually, if we do not have data prior to 1845, we may not know what the maximum field is. We might be far below the 90% of maximum that the story suggested.

They actually can tell what the magnetic field was like from samples dug out of the earth (fossils and geologic specimen). The magnetic field of the time polarizes elements in the sample, showing direction and magnitude. They use volcanic remains a lot because of its high metal content and nature to cool rapidly, conserving the polarization.

During 'flipping', some samples showed substantial field shift within 24 hour spans, when the field is in major flux globally.

[st_swithin]

Platinum jewelry is outselling gold jewelry these days. How much of a margin of conductivity does Pt have over Au? I wonder if there's a connection...

[Q Classic]

silver's still the best conductor.

[st_swithin]

Yeah, but it's brittle. Copper's good too, but it oxidises too readily. Pt is brittle too. I just know that Pt is a little more conductive than Au. And silver apparently doesn't convey the 'bling' quite as well as Pt.

[Q Classic]

silver is shiny. what more bling could you want?

[st_swithin]

Hey man, I don't create the trends, I just observe them. If it were up to me, we'd all be wearing head-to-toe neon day-glo a'la 1980's new wave - bada bling!

[Q Classic]

i'm glad you're not in charge.

[st_swithin]

Oh, you should be. You should be.

[Zero]

I wish I was in Chi...
:9

[CerberusIV]

Originally posted by Ned
CyberusIV, wouldn't the core also rotate the same as our atmosphere - with the flow nearer the poles being opposite that near the equator?

I don't remember all the details, it is a few years since I studied this, but the outer core behaves as a liquid and the flow pattern is complex. Also it is affected by whether there is continental or oceanic crust at the surface as continental crust is thicker and insulates the heat flow better so it is slightly hotter under the continents. The hotter is it the more easily it flows and so that affects field strength. Things like plumes causing hot spots like Hawaii complicate things further.

Apologies for a less than full explanation, it is a developing area of science involving a lot of research and the way it is understood is changing fairly rapidly.

[Ramo]

I recently read some stuff about mantle convection. Apparantly, it has a whole lot to do with the Earth's magnetic field. However it's a ***** to understand since Navier-Stokes governs it (and apparantly an inviscid flow is somehow a good approximation hmmm: - gotta love fluid dynamics).

[Dauphin]

Originally posted by Anun Ik Oba

During 'flipping', some samples showed substantial field shift within 24 hour spans, when the field is in major flux globally.

I have a hard time believing a science that deals in aging rocks and fossils to within thousands of years can measure the change in global flux to within a day.