Talk:Geomagnetic reversal

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[edit] Request

Could anyone put in some information about the effects a polar reversal would have on humanity?

I agree - info in Magnetic polarity reversal should be merged into this article. -Vsmith 02:52, 16 August 2005 (UTC)

Agree Stevelinton 22:02, 26 August 2005 (UTC)

I am also wondering about the affect of such an event on computer storage - sureley a entire REVERSAL would cause every bit of data in the world to be corrupted? Thoughts? Any experts out there! Sounds like we are due for one :|

The Earth's magnetic field is very weak: around 30 to 70 microteslas at the surface. Compare this range of values to strengths of other types of magnets to get an idea (Tesla). Thus, a polarity reversal would have no tangible effect on magnetic storage media. Furthermore, the current decrease in the strenght of the Earth's field is not likely to be a precursor to a reversal. It is most likely natural variability. For further information: Constable, C. and M. Korte, 2006. Is Earth's magnetic field reversing? Phys. Earth Planet. Inter. 246, 1-16. --Octupole 01:33, 3 July 2006 (UTC)

[edit] Typo

Changed "casual mechanisms" to "causal mechanisms"

[edit] About "Future of the present field"

This section contains an error. It says in the first sentence: "...cause the field to disappear, albeit temporarily...". This is not true. The geomagnetic field does not disappear during a reversal; not even temporarily. The strength of the field does, however, drop down to 10-20 per cent of the value it has during a period of stable polarity. More specifically, the geomagnetic field has dipole and anomaly parts. The dipole part does, indeed, reverse by going through zero (no dipolar field) but the anomaly part (the field of higher multipoles) does not disappear.--Octupole 22:40, 16 December 2005 (UTC)

Thank you for your suggestion! When you feel an article needs improvement, please feel free to make whatever changes you feel are needed. Wikipedia is a wiki, so anyone can edit almost any article by simply following the Edit this page link at the top. You don't even need to log in! (Although there are some reasons why you might like to…) The Wikipedia community encourages you to be bold. Don't worry too much about making honest mistakes—they're likely to be found and corrected quickly. If you're not sure how editing works, check out how to edit a page, or use the sandbox to try out your editing skills. New contributors are always welcome.—WAvegetarian•CONTRIBUTIONSTALK• EMAIL•15:14, 14 February 2006 (UTC)

[edit] Recent PBS documentary

Last night a PBS documentary aired on television that proposed that the Earth's magnetic field is decreasing at a much faster rate than what we currently suspect. (It predicts the field could collapse by the end of this century.) Is there any new evidence to substantiate this claim? Spectheintro 14:40, 25 October 2006 (UTC)spectheintro

That NOVA first aired in 2003. You can look for new evidence by finding research by the people named in the documentary, then looking for references to that research. Google Scholar may find something recent. (SEWilco 18:14, 27 October 2006 (UTC))
It's not so much of a reversal as an excursion or nonexistence. Information about this seems more suited to the pages on geomagnetic excursion or Earth's magnetic field. Hyacinth 09:21, 13 January 2007 (UTC)

[edit] Query

I looked on http://www.newton.dep.anl.gov/askasci/env99/env034.htm and it says that the magnetic field does not protect the earth from solar flares. Apparently it just guides the ions of the solar wind to the north and south pole, where they produce the Northern and Southern Lights. Am I missing something?

The earth's field does let some particles through to the poles, but protects us from the brunt of the solar wind. Most of the solar wind (energetic particles from the sun) is guided around the planet by the earth's field. What reaches the poles is a small flux of particles resulting from magnetic reconnection events in a very small area of the earth's magnetic tail. In addition, the inner parts of the earth's field confine these particles fairly well so they "leak" onto the poles at a slow rate and at low energy. The field certainly provides a large measure of protection. —The preceding unsigned comment was added by 198.125.178.250 (talk) 22:41, August 22, 2007 (UTC)

[edit] Movement of magnetic pole

I have a question regarding the present field. If the magnetic north and south pole are moving at a rate of 40km a year and in a few thousand years, they will have switched completely; In half that amount of time, will the equator run through what is now the arctic and antarctic? And will this effect temperatures there? (Aindriú Conroy 12:30, 09 January 2007

The location of the magnetic poles is not known to be connected to the poles which are the axis of rotation of the Earth. If the poles moved to the equator yesterday, the planet would still be spinning the same way. The north pole of rotation would still be in the Arctic Ocean and the south pole of rotation would still be in the Antarctic. (SEWilco 02:53, 10 January 2007 (UTC))
Actually, I believe the dipole moment of the earth's field (the primary component) is connected through internal processes to the earth's rotation. The rotation axis and magnetic axis are therefore usually roughly aligned (or anti-aligned). Also, the present geographic movement of the magnetic axis constitutes a precession around the axis of rotation (eg, its latitude is not changing much). It is not moving towards the equator.

[edit] Effects of geomagnetic reversal

What are the effects, rather than causes, of geomagnetic reversal? Hyacinth 09:24, 13 January 2007 (UTC)

The effects are poorly known. Perhaps someone else can cite studies, but for sure we know that, for example, mass extinctions do not coincide with reversals (not even minor spikes in extinctions, as far as I know). Of course, complex modern human brains have not been present for a reversal in the past, nor have the complex electromagnetic gadgets our modern society depends on. Good question. Geologyguy 15:58, 13 January 2007 (UTC)

How would atomic warfare influence this process? Can regional conflicts damage the magnetic system sufficiently to speed the reversal up? Would the geomagnetic reversal be the least of our concerns in that case, or could it be the most relevant unexpected side effect? Should a link between the two articles exist if there is one scientifically? --lynX

Earth's magnetic field does a reliable job of withstanding the energy of solar events. I doubt any of our weaponry - even weapons built solely to release electromagnetic energy - carries enough energy to alter the magnetic field. In fact, until we know more about the process that creates Earth's magnetic field, I'm not certain that ANY plausible amount of external energy could alter the magnetic field. If the field is caused by the motion of fluid, then you'd need enough energy to change the momentum of something like one billion trillion tons of liquid rock. 205.175.225.22 (talk) 17:40, 11 December 2007 (UTC)
First someone has to find and write about such information. Then we can consider whether it should be in this article. -- SEWilco (talk) 18:22, 11 December 2007 (UTC)

[edit] Image

Hi. What happened to the image showing a map, arrows, and flows of magnetism? I think it was on this article, but I'm not sure. If it still exsists, can you link to it? Why was it removed? Was it because there were to many images? Thanks. AstroHurricane001(Talk+Contribs+Ubx) 22:33, 8 February 2007 (UTC)

[edit] No sources?

Shouldn't there be enough quotes and sources in the PBS NOVA episode to lead to further resources?


Causes --- Scientific opinion is divided on what causes geomagnetic reversals. Many scientists believe that reversals are an inherent aspect of the dynamo theory of how the geomagnetic field is generated.  !!In computer simulations, it is observed that magnetic field lines can sometimes become tangled and disorganized through the chaotic motions of liquid metal in the Earth's core. !! needs a reference. —Preceding unsigned comment added by Reidbold (talk • contribs) 22:05, 12 November 2007 (UTC)

[edit] Things to implement in the article

McDonald and Gunst in 1968 showed that the current decay of the dipole field is not a decay of the total field, but rather a transfer of energy from the dipole field to the quadrupole and higher fields. There is thus no indication that there will be a reveral any time in the foreseeable future. There may be one, but there is no indication of it.

McElhinny and Senanayake in 1982 showed that the dipole moment fluctuates over periods of a few thousand years, and that decreases in intensity are typically followed by increases. Their data show that the dipole field, compared to present, was circa 20% weaker 6500 years ago and then circa 45% stronger 3000 years ago. There is thus little or no correlation between the dipole trend and an imminent geomagnetic reversal. I think a large portion of the article may have to be rewritten, as it seems to imply otherwise.

--76.224.92.141 17:51, 26 August 2007 (UTC)

[edit] History of the idea

Could we have some information on the genesis of the idea, and the evidence that lead to its acceptance? PoochieR (talk) 09:26, 24 January 2008 (UTC)

I think I just picked up some papers on that. -- SEWilco (talk) 15:53, 24 January 2008 (UTC)
The History section has a lot more now. Any more details needed? -- SEWilco (talk) 01:35, 22 February 2008 (UTC)