I'm sure most of you heard about this story. Tampa, FL airport runways needed repainting to align with the shifting pole. I knew the poles moved, but 40 miles a year is surprising. There's an interesting science friday interview on NPR about it.

I would surmise the poles are shifting based on "wobbulation" of the Earth about its axis. Some call it precession if I remember right.

It's more proof of global warming, O ye doubters!

Seriously though, I don't think they know why the magnetic pole shifts around much less why the polarity would suddenly reverse as apparently it has done several times over history.

HJ

HJ,

In fact we know quite a bit about polar wandering and polar shift. MoBOB was somewhat correct, precession does have something to do with earth movement, but that movement is much slower than the wobble introduced by the fact that the earth is a slow gyroscope (think of a top as it slows down). The convection cells in the outer core (where the magnetic field is produced) are also wobbling, not necessarily in the same sense. The motion of the two of them together might be in sync (slow polar wandering) or out of sync (fast).

As for the reversals, they are probably not sudden - at least in human terms - but take several thousand years (if some modelers are correct, we might be in the beginning of one) and once again are introduced by changes in the circulation of the outer core.

Respectfully,

Jerry

Hmmm. Well, OK, kind of.

We do know quite a bit about the axial tilt of the earth and the wobble thereof.

What I don't think we know well is the relationship between the wobble of the geographic pole and the changing position of the magnetic pole. The two probably do have a relationship, but I have yet to see a well articulated explanation of exactly how they are related.

I think we are more reactive than predictive with respect to the changing position of the magnetic pole. We can observe and correct, we can establish general easterly and westerly trends, but we can't always predict where the magnetic pole will be with the kind of precision we can with, say, the positions of the planets or other heavenly objects. My understanding is that we can't even begin to predict the movements of the magnetic pole with anything approaching that level of precision.

Hope that clarifies what I meant in my previous post.

HJ

HJ,

My description may be a little short, for a better introduction and some good links, please see:

http://www.nasa.gov/vision/earth/lookingatearth/29dec_magneticfield.html

Gary Glatzmer and Paul Roberts (UC Santa Cruz) are among the leaders in this area.

Respectfully,

Jerry

Good Info, thanks for sharing.

Ah, thank you. The science has progressed further than I knew.

They still can't predict with precision, but at least they have a general model for what's going on.

Did you guys catch that diagram with multiple north poles and multiple south poles? That might make land nav just a little more complicated.

HJ

And in only a few centuries it COULD happen!! Stand by for further information (but don't hold your breath ;-).

The best,

Jerry

I read some interesting information about the magnetic pole shift here Planet Shifting.