Talk:Geomagnetic reversal/Archive 1

Archive 1

Request

Why is there no mention of the coupled disk dynamo hypothesis? E.g., http://eprints.lse.ac.uk/22242/. It is a simple model with chaotic behavior. —Preceding unsigned comment added by 75.165.85.58 (talk) 06:48, 15 June 2009 (UTC)

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)

Current magnetic media has become more and more stable over the years. Small fluctuations which would have been disasterous twenty or thirty years ago are now insignificant. One should also consider that the preliminary research in this area was the discovery of reveresed polarities in magnetic rock. This suggests that current polarities will remain but that NEW materials will have to be adjusted. The question may be moot anyway as we become increasingly dependant upon optical media which is not affected by electromagnetic fields.

Such fields are very important in navagation and the system of TVMDC for working compass readings to and from True readings is an important example. The difference between True and Magnetic is Variance and this represents the constant 'wandering' of the magnetic poles. Since they are moving all of the time anyway and are not 'fixed' I expect that any problems we would expect with pole reversal would already have been observed during major variations of the magnetosphere.—Preceding unsigned comment added by 24.235.213.213 (talk • contribs) 23:21, 4 January 2009

The Earth's magnetic field is rather irrelevant to a computer's environment. Walk around an office with a compass and you'll find much stronger magnetic fields in steel furniture and the building's structure. -- SEWilco (talk) 06:12, 5 January 2009 (UTC)

Typo

Changed "casual mechanisms" to "causal mechanisms"

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)

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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)

On reading all the various articles on polar shifting, would gravity change any. On free fall one accelerates at 9.81 feet per second squared untill the resistance of the object {jump suit} refraction and friction of the air becomes a sate of equilibriam around 120mph unless you are shaped like a dart, would that change any. Will we fly out to space with zero gravity. Craig 9 th grade aug 2009. —Preceding unsigned comment added by 66.91.180.152 (talk) 03:03, 26 August 2009 (UTC)

Craig, no, the magnetic field is a separate phenomenon from gravity. The acceleration we experience due to Earth's gravity (9.81 meters/second^2 ~32.2 feet/second^2) originates from the earth's mass, not its magnetic field.BlearySpecs (talk) 00:38, 24 September 2009 (UTC)

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)

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.

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)

Actually the magnetic field is generated not only through our molten mass but the magnetic minarets that is contained in it, i.e., Iron. If you have ever made a magnet all you require is a magnetic source and an abundance of electrical protons and neutrons. this is what our core is made off, now our planets core is spinning that is a big part of gravity, but the mass will not stop spinning, the energy to drop that is too vast, the world would slow down and start tilting until the new magnetic field was aligned then the world would continue on it's orbit around the sun. There may be a few days where one part of the world is in darkness, but in a hole humanity should recover. —Preceding unsigned comment added by 66.91.180.152 (talk) 03:28, 26 August 2009 (UTC)

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)

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)

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)

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)

Effect of solar storms on geomagnetic reversals

A recent Scientific American article discusses the effect of solar superstorms on the earths magnetic field. could a solar storm be large enough to reverse the earth's magnetic field? Frazer Smith (talk) 23:44, 29 July 2008 (UTC)

Earth's rotation affected?

Is it true that Earth's rotation is reversed when geomagnetic reversal occurs? —Preceding unsigned comment added by 96.32.75.226 (talk) 18:21, 18 October 2008 (UTC)

No. thx1138 (talk) 23:25, 25 November 2008 (UTC)

Pole Reversal does NOT affect polarity of electronic components

There is an urban legend propagated mostly by scientifically uneducated members of what is more commonly known as the "New Age" community, that when the earth undergoes a pole reversal in 2012, the polarity in all electronic circuits on earth will change as well, thus permanently disabling them. This idea is pseudo-science, as the polarity of the magnetic field of earth has no bearing on the direction of the flow of current in an electronic circuit.

Not all newagers believe this mistaken idea, but it is a tempting since it supports their wishful thinking that the old paternal materialistic western system of spiritual ignorance will collapse and give way to a maternal, metaphysical, eastern system of spiritual enlightenment--i.e., "the Age of Aquarius".

Thus, I made the April 15, 2009 deletion of the sentence in the article that conveyed this scientifically unfounded idea. Please do not revert it back to the former content that requested a citation was needed, as a citation for this idea will never be found in any legitimate scientific book or article.72.84.75.117 (talk) 17:03, 15 April 2009 (UTC)

Archive 1

Are geomagnetic field reversals analogous to the sunspot cycle?

Sunspots apparently work on a 22.1-year cycle. Each cycle contains two maxima during which sunspots are most prominent and magnetic field flux tubes form prominences on the surface of the Sun; these are the times when the major component of the stellar magnetic field reverses. Interestingly the cycle may be driven by the 22.34-year periodic relationship between the average positions of Venus, Earth, and Jupiter.[1]

• Is the analogy between this and geomagnetic field reversal accurate?
• During the period of weakest magnetic field, will there be pairs of "earthspots" (local N and S poles) on which aurorae might focus?
• Could the geomagnetic field reversals also be affected by planetary conjunctions (or perhaps, changes in the Earth's orbit?)?

Just curious... Wnt (talk) 04:57, 3 March 2010 (UTC)

On Radiation Shielding

The part on radiation appears to be original research (already marked for citation and as original research). It is contrary to this article. Proceeding to delete. Geeteshgadkari (talk) 13:50, 26 April 2010 (UTC)

Diagram of full history

{{reqdiagram}} It would be interesting to have at least a link to a diagram showing the full known history of magnetic polarity, beyond the nice existing graph going back to 5 million years ago. -- Beland (talk) 15:47, 10 June 2010 (UTC)

I remembered seeing one the last time I wandered onto this topic. As far as I can tell, we had File:Lowrie.gif which was deleted in favor of a Commons version in August 2008, and then the Commons version was deleted in November 2009. You could take it to WP:DRV and try to get it undeleted, or if you can find raw data it would be relatively easy to find someone to recreate the diagram from scratch. Anomie⚔ 02:24, 25 July 2010 (UTC)

I finally managed to find the data in a few papers, and have created the requested diagram. Anomie⚔ 16:45, 2 September 2010 (UTC)

Richard Muller's hypothesis

I don't think the origin of reversals is controversial. No paleomagnetist has cited Muller's paper, and I have yet to hear anyone even mention it at geophysics meetings. The hypothesis is presented in two paragraphs and the evidence is very skimpy (a major counter-example, the K-T boundary, has to be explained away). As for the computer models, although they necessarily make approximations, they make a convincing case that reversals can occur as a natural part of the dynamo action. I would say that Muller deserves no more than a footnote. RockMagnetist (talk) 15:51, 3 September 2010 (UTC)

Science News resource

Pole flips tied to plate tectonics "Lopsided arrangement of continents could lead to reversals in Earth's magnetic field" by Alexandra Witze November 19th, 2011; Vol.180 #11 (p. 9) 97.87.29.188 (talk) 22:29, 25 November 2011 (UTC)

Thank you for the link. RockMagnetist (talk) 01:48, 26 November 2011 (UTC)

You are welcome. (",) Thank you for your politeness. 97.87.29.188 (talk) 00:51, 29 November 2011 (UTC)

Will this really happen

I know people are saying that this is going end the world and mass chaos will strike Earth with giant tsunamis and large earthquakes, in the winter of this year, but I've also heard that the poles will shift in 5,000 years or more because people can't predict the poles shifting because it's not like an alarm clock: you can't set it off at any time. If anybody has the answer it'd be happy to hear that. Thanks -User:Kyleronco Not logged in — Preceding unsigned comment added by 68.37.239.161 (talk) 14:00, 24 June 2012 (UTC)

As you might note in the article, it's not like flipping a switch; there's nothing sudden or even really noticeable about the reversals on a human scale. They occur over the course of thousands of years. It's a very gradual process that we'd have ample time to work out how to adapt any instruments dependent on a more consistent geomagnetic polarity. And I don't see why it would cause tsunamis or earthquakes. There was not apparently any associated increase in volcanic or tectonic activity with previous reversals. Saerain (talk) 11:17, 14 August 2012 (UTC)

Figures in lead not in article

I see I erred in my reading of the sentence when I put my summary in when tagging but the figures are still not in the article. If 0.1 million years isn't in article one would think 100,000 years would be (0.1 of 1 million) but it's not either. This needs fixing.--Daffydavid (talk) 01:18, 22 September 2012 (UTC)

Just a word of congratulations to the editors

From an anonymous user. This is one fiiine article, guys. Learned a lot. Thanks. — Preceding unsigned comment added by 24.201.192.48 (talk) 05:28, 8 December 2012 (UTC)

Thank you for letting us know! RockMagnetist (talk) 16:53, 10 January 2013 (UTC)

Compasses

Wouldn't compasses become useless while a reversal was occurring? Tad Lincoln (talk) 21:16, 21 December 2012 (UTC)

No. The direction of magnetic north already varies from place to place, and maps need to include the local declination. The declination would simply change more rapidly with location. Reversals probably happen slowly enough that we could easily keep the maps up to date. RockMagnetist (talk) 16:49, 10 January 2013 (UTC)

A what now?

A caption contains the text: "The tubes represent magnetic field lines". What exactly is a "magnetic field line"? Are these lines of equal potential? Concentrated flux? What? It's all photons at the bottom, and they're points, not lines. Maury Markowitz (talk) 13:55, 10 January 2013 (UTC)

See Magnetic field#Magnetic field lines. Vsmith (talk) 14:02, 10 January 2013 (UTC)

A rambling discussion that does not apply to this specific case. Once again, what exactly are the "tubes" in the diagram illustrating? I guarantee it's not representing the self-organization of iron filings into clumps along arbitrary boundaries. I suspect it illustrates directional vectors, but the density and selection is not stated. I'm sure the program has some basis for placing the "tubes" in specific locations and not others... what is it? Maury Markowitz (talk) 15:21, 10 January 2013 (UTC)

On the contrary, Magnetic field#Magnetic field lines applies very well to this figure - particularly the first two paragraphs. The only thing I would add is that, in a small region, the strength of the field is proportional to the density of field lines. RockMagnetist (talk) 16:41, 10 January 2013 (UTC)

Human Society?

The section titled "Effects on biosphere and human society" does not have any clear reference to effects on Human Society. Perhaps this section should merely by titled "Effects on the biosphere". — Preceding unsigned comment added by 64.111.157.72 (talk) 07:27, 2 May 2014 (UTC)

I agree, and I have modified the heading. RockMagnetist (talk) 14:14, 2 May 2014 (UTC)

Intro seems self contradictory

The intro has the following section:

Most reversals are estimated to take between 1,000 and 10,000 years. The latest one, the Brunhes–Matuyama reversal, occurred 780,000 years ago. A brief complete reversal, known as the Laschamp event, occurred only 41,000 years ago during the last glacial period. That reversal lasted only about 440 years with the actual change of polarity lasting around 250 years.

This seems like a contradiction. We say that the latest "one" occurred 780 millennia ago, but then talk about a brief "complete reversal" just 41 millennia ago. What does the "one" pronoun refer to? A brief complete reversal is still a reversal. Either "one" refers to something other than a reversal or the sentence is incorrect. --Bertrc (talk) 00:13, 5 May 2014 (UTC)

I came here just now to say exactly this. I would make a change, but I'm a total random reader on this topic. This article got me interested to learn more, but this intro is pretty confusing.--Jimbo Wales (talk) 23:45, 9 January 2019 (UTC)

@Bertrc and Jimbo Wales: The short answer is that the Laschamp event is usually called an "excursion". The main distinction between excursion and reversal is that the latter lasts longer, although the cutoff is somewhat arbitrary (about 10,000 years according to one source). It happens that I have been thinking of raising this article to GA or FA level, so you may see a better discussion soon. RockMagnetist(talk) 16:19, 10 January 2019 (UTC)

This should really be clarified in the introduction then. Right now, it contradicts itself rather than clarifying things. Even in the second paragraph, the statement "with some periods lasting as little as 200 years" doesn't reconcile with the later statements and the third paragraph uses an entirely different definition of excursion. StuartH (talk) 05:31, 19 January 2019 (UTC)

events ... classified as excursions rather than full geomagnetic reversals

I don't see the full statistical evidence and justification of that. If the earth's magnetic field reverses twice (or an even number of times) in succession, then it is in the same position as it was where it started. If it reverses once (or three or any odd number of times), then it is opposite from where it started, however long it remains in the new orientation.

It seems very simple: over time, the earth's magnetic poles tend to line up with the earth's axis of rotation, one way or the other, with only two possible orientations.

The magnetic remanance of the solid inner core as well as the crust of the earth may be overestimated along with the distinction between temporary and permanent changes.

Other powerful effects seem to actively prevent the earth from remaining in one of two possible stable or metastable magnetic orientations for too long a geologic time span. 74.124.124.30 (talk) 21:31, 19 December 2019 (UTC)