A magnetic reversal in progress?
The South Atlantic Anomaly (SAA) is known to be growing in extent and spreading westwards from South Africa, as the Earth’s internal magnetic field rapidly weakens in this region. This may be early evidence of a forthcoming reversal in the direction of the Earth’s internal magnetic field. We do not know in detail precisely what occurs during such reversals, including the changes observed in the magnetic field and the time a reversal takes to complete. However these factors are important in knowing where the radiation risk may be increased and how the atmosphere might respond.
Earth’s magnetic field has had many highs, lows and reversals in its past. The last reversal was around 800,000 years ago. So the Earth is known to be able to re-generate its field and has done so during human pre-history. Understanding the development of the SAA may therefore be significant in understanding the reversal process and its impact on life and the natural environment.
Serendipity said:In second one he is demonstrating that sun is setting about 40 degrees away from magnetic west.
Laura said:The movement of the magnetic pole has nothing to do with axial orientation. The magnetic pole moves all over the place all the time. The pole could even reverse entirely and not have any effect on the axial orientation.
So, while this is interesting, it's probably not significant in the way the guy is suggesting.
Martina said:hello! what is suppose to happen when/if the poles reverse ? is this worse then comets and floods, pest...
sorry, I'm a bit slow :)
October 31, 2001
Q: (L) Now according to these guys who are writing this web page about pole shift, they say it can be predicted where the poles will shift to. Is this in fact the case?
Q: (L) Why can't pole shifts be predicted? Can't we know where the new pole will end up?
A: Chaotic function here.
Q: (L) Okay, in a pole shift does the lithosphere of the planet slide on the core? (A) No. We have to be very precise. There are three possible things that would come under the name pole shift. Only one of them may come, or two, or three, okay? And these are the following -1) the axis of rotation with respect to stars is changing, straightening out for instance; this is one thing; while all the rest goes with the axis, the lithosphere and the magnetic field. 2) Second, the axis stays where it is, maybe it shifts a little bit; the lithosphere stays where it is - maybe it wobbles - but the magnetic field changes: for instance reverses. 3) Third, axis stays, magnetic field stays, but the lithosphere is moving. So that's three ways a pole shift can happen. And of course there are things that come together. The most dramatic one which is seen from outside is when the axis of rotation changes. The next dramatic one is probably when the lithosphere changes. And the third of unknown consequences is when the magnetic pole changes, okay? So, we want to have an understanding what will be the main change. (L) Well I guess we ought to ask an even more basic question: are we looking at a pole shift happening? That's starting at the beginning. (A) Alright. (L) In the next ten years. Is a pole shift possible in the next ten years?
Q: (L) Is a pole shift of the axis...(A) Honey, you ask if the pole shift is possible, of course it's possible. But suppose it's almost zero probability? 'Is it possible' is not the right question. 'Is it going to happen?' That's a question. (L) Okay you ask, carry on. (A) Are we looking at a pole shift during the next ten or so years with a high degree of probability?
Q: (A) In this concept of pole shift, what would be the main feature of this pole shift, of all those which we were discussing?
A: New axial orientation, and magnetic reversal.
Q: (L) That's fairly dramatic. (A) Alright, now, change of axis or orientation of axis of rotation: can we say we would straighten up, getting almost perpendicular to the ecliptic? Or the other possibility is that it will fall down being almost parallel to the ecliptic. The third is that we'll flip completely by 180 degrees. We know it's highly unpredictable, but can we have a clue from which one is, so to say, dominate?
A: Perpendicularity will be restored.
Q: (A) We know the axis will change dramatically and magnetic reversal will happen. You didn't mention a change or shift of the lithosphere alone. Can we...
A: Lithospheric shift will feature to some extent.
Q: (A) But, that means eventually that the equator will almost not change because...
Q: (A) So it will just shift a little bit, but its not going to go to Hawaii? (L) Oh rats! That was my theory! Well, it was a good idea. (A) What about changes in the lithosphere: can we predict a little bit of change in geography, coming from motions in lithosphere and changes in water level?
A: Chaotic features predominate but in general it will be safer inland and in mountainous areas since less folding occurs in such locations.
Q: (A) Now, the major, the change of the orientation of the axis, what would be the main trigger, force, or activity, or what kind of event will trigger this change of the axis?
A: Cometary bodies.