Earth's magnetic field not about to flip

[RichardR]

I think my headline more accurately reflects the story than the CNN one: (http://www.cnn.com/2003/TECH/science/12/12/magnetic.poles.ap/index.html)

SAN FRANCISCO (AP) -- The strength of the Earth's magnetic field has decreased 10 percent over the past 150 years, raising the remote possibility that it may collapse and later reverse, flipping the planet's poles for the first time in nearly a million years, scientists said.

At that rate of decline, the field could vanish altogether in 1,500 to 2,000 years, said Jeremy Bloxham of Harvard University.

Hundreds of years could pass before a flip-flopped field returned to where it was 780,000 years ago. But scientists at a meeting of the American Geophysical Union cautioned that scenario is an unlikely one.

"The chances are it will not," Bloxham said Thursday. "Reversals are a rare event."
Don't tell Gregg Braden!

[Andonyx]

I'm not conversant enough with geology or other relevant disciplines ot make an educated asessment, but I have seen other articles in equally reliable publications in which scientists have remarked surprise that it hasn't flipped already...

I saw that article earlier and I thought it curious because I've seen stuff rcently, (Popsci? Maybe? I'll dig around.) That says essentially no one can predict right now because it's fairly erratic, but wouldn't surprise anyone if it happened soon (on a geological scale, obviously, not a human scale.)

[hgc]

Quick, Luci! Predict it! You'll score a hit!

[andre]

So what's new? The Earth magnetic field has not been so strong ever before in the past several million years. Just like global warming. It was bound to decrease. There is no way to predict what's happening next and when, just a stabilisation, a magnetic excursion or a flip.

[athon]

Whew. That's good, because I've seen what removing it can do. 'The Core' displayed in a very visual way what the radiation in space is capable of doing, and I for one do not want even the smallest gap to appear in the magnetic field. It would be like having a flamethrower move its way across the surface of the planet!

Athon

[andre]

Hey Athon, Films and not documentaries and no science. Films are to be sensational. The only thruth in "the core" is that the Earth core turns a bit independent of the rest. It spins slightly faster nowadays, than the rest of the Earth, to complete an orbit extra orbit, every 400 years.

That has probably been the basic idea for the film but the rest of the film is a contempt of physical laws. Forget it.

[RichardR]

Originally posted by andre
Hey Athon, Films and not documentaries and no science. Films are to be sensational. The only thruth in "the core" is that the Earth core turns a bit independent of the rest. It spins slightly faster nowadays, than the rest of the Earth, to complete an orbit extra orbit, every 400 years.

That has probably been the basic idea for the film but the rest of the film is a contempt of physical laws. Forget it. Your new word for today (http://dictionary.reference.com/search?q=irony) ;)

[athon]

Originally posted by andre
Hey Athon, Films and not documentaries and no science. Films are to be sensational. The only thruth in "the core" is that the Earth core turns a bit independent of the rest. It spins slightly faster nowadays, than the rest of the Earth, to complete an orbit extra orbit, every 400 years.

That has probably been the basic idea for the film but the rest of the film is a contempt of physical laws. Forget it.

Haha, thanks Andre. I should have put something in to suggest I was being sarcastic.

Athon

[T'ai Chi]

If it flipped (and I'm not exactly sure what that means), what would happen?

[Small Town Jesus]

Originally posted by T'ai Chi
If it flipped (and I'm not exactly sure what that means), what would happen?

There's a good thread about this here. (http://www.randi.org/vbulletin/showthread.php?s=&threadid=30902)

STJ

[andre]

Athon Richard, got me. it worked :D

T'ai Chi
What would happen during a flip? Well there are no records of geologic or biologic reactions. Certainly no catastroph or extinction. But it would be interesting to see pigeons navigate.

The variation in the magnetic field is probably slow enough for life to adapt if animals really use the magnetic field.

Again. Earth magnetic field is very strong at the moment and it is bound to decease as you can see here:

Global Changes in Intensity of the Earth's magnetic fied during the past 800 kyr, Guyodo & Valet (http://www.geo.uu.nl/~forth/publications/Related_pubs/Guyodo99.pdf)

http://home.wanadoo.nl/bijkerk/Gubbins.jpg

Notice the field reversal or flip at 780,000 years ago, a.k.a. as the Brunhes-Matuyama boundary.

[Darwin'sGoat]

I recently caught a Nova episode about this.

http://www.pbs.org/wgbh/nova/transcripts/3016_magnetic.html

They were talking about how scientists track flips through samplings of solidified magma flows. The one bit that really caught my attention was how one flip (which normally take place slowly over many hundreds and thousands of years) jumped over the course of about 10 days and can be seen all within one lava flow.

[andre]

Well, I'm not sure what you mean about that flip in ten days. Glatzmaier talks about steps of ten days between calculations in his computer model.

There used to be a sharp double flip, however, where the poles seemed to switch out and back in a few years. The "Gothenburg" flip.

The Gothenburg "Flip"
In the case of the Gothenburg "flip," which Hancock (1995) misidentified as a "magnetic reversal, FOG again provided a poorly researched analysis. The still unproved Gothenburg "flip," if real, was a rapid and brief change of magnetic field that occurred about 12,350 BP. It was not a real magnetic reversal. The last true magnetic reversal occurred 730,000 years in the change from the reverse polarity of the Matuyama Magnetic Epoch to the normal polarity of the Brunhes Magnetic Epoch. The Gothenburg "flip," as proposed by Morner (1971) and reported by Anonymous (1972), is more properly called a "magnetic excursion" because the Earth magnetic field did not reverse itself permanently but briefly changed without complete reversal over the period of a few years.

http://www.intersurf.com/~chalcedony/FOG10b.html

It has dissapeared totally, apparantly a fake, those things happen when the sediment cores that are drilled break up and are put back reverse. The debunking was never publiced.

[Darwin'sGoat]

Sorry I was misremembering it. It wasn't a complete flip, it was a chaotic period mid-flip where a single flow recorded a 60 degree change over a period of aproximately 10 days.

NARRATOR: The field started out pointing south, but as it weakened the direction of the field began to change erratically. After 300 years, it had swung a full 180 degrees to point north, and the field strength started to recover.

ROB COE: But it couldn't hold that polarity, and it fell back to...reversed and the intensity crashed again.

NARRATOR: Once more the Earth's magnetic shield practically disappeared, this time for 3,000 years. What was left was changing so fast that Rob found a flow that captured these wild gyrations even as the lava cooled.

ROB COE: And what we found was even harder to believe. The quickly chilled margins in the bottom and the top had one direction, like that of the underlying flow, and the middle portion had a direction that was sixty degrees farther away. It was just as though, while the flow cooled, the field had moved sixty degrees, which if you calculate it out, that comes to about six degrees of movement per day. If we were observing this with a compass, you would be able almost to see the motion with your eye. It was truly astonishing and extraordinary.

[Prester John]

I think you'll find they match perfectly with the appearances of planet X

[andre]

match perfectly with the appearances of planet X

Got it now, learned a new word, the correct answer is: no, it was Venus doing triple somersaults, while being chased by Immanuel Veliskovsky.

Yes DG those rapid magnetic changes are the Paleo Magnetic Excursions, they are assumed to originate from chaotic turbulence in the fluid outer core that seems to be captured in Glatzmaiers model.
http://www.es.ucsc.edu/~glatz/geodynamo.html

[TillEulenspiegel]

Earth's magnetic field not about to flip

? taht yas uoy s'ekam tahW

[Phaycops]

I like this representation of pole reversals better. I feel it gives a better picture of the complete lack of any kind of pattern to them. Plus, it's the one I'm used to seeing :P Check it out:

http://gemoc.anu.edu.au/course/geol3017/figs_jpg/fig46.jpg

[Eos of the Eons]

Well that's no fun. I was looking forward to all the compasses in the world being all @ssbackwards.

[Daffy Duck]

I think Darwin's Goat is referring to the Pringle Falls (Oregon, USA) excursion:


http://www.blackwell-synergy.com/links/doi/10.1046/j.1365-246X.1998.00680.x/abs/

Andre, we've previously discussed this and Glatzmaier's comments about it, but I can't find that link...

Though this is stating 1200 years, not "10 days."

[andre]

Hi Daffy,

I guess you're right about that. There was also a reference to a remarkable uniform duration of an excursion of about 6000 years.

On the other hand, the Mono Lake excursion that Langereis rejected as not being a global event showed up also in famous high resolution ODP core 983 (California) and was rather short (27.0 - 25.5 Ky)

http://www.blackwell-synergy.com/links/doi/10.1046/j.1365-246x.2000.00001.x/abs/

Still not nearly enough for six degrees per day.

[NileQueen]

The difference between an excursion and a reversal:


http://www.blackwell-synergy.com/servlet/useragent?func=synergy&synergyAction=showAbstract&doi=10.1046/j.1365-246x.1999.00810.x&area=production&prevSearch=keywordsfield%3A%28%22excursion%22%29

Geophysical Journal International
Volume 137 Issue 1 Page F1 - April 1999
doi:10.1046/j.1365-246x.1999.00810.x


The distinction between geomagnetic excursions and reversals
David Gubbins
Summary

Two recent studies of the geomagnetic field in the last 1 Myr have found 14 excursions, large changes in direction lasting 5-10 kyr each, six of which are established as global phenomena by correlation between different sites. The older picture of the geomagnetic field enjoying long periods of stable polarity may not therefore be correct; instead, the field appears to suffer many dramatic changes in direction and concomitant reduction in intensity for 10-20 per cent of the time. During excursions the field may reverse in the liquid outer core, which has timescales of 500 yr or less, but not in the solid inner core, where the field must change by diffusion with a timescale of 3 kyr. This timescale is consistent with the remarkably uniform duration of well-dated excursions. The disparity of dynamical timescales between the inner and outer cores, a factor of 10, is consistent with the 10 excursions between full reversals.