13-12-2003 23:41									#61
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quote: All the cool kids will die off of skin cancer

quote: Then the chicks will be ours!!!!!!!!

Except that the chicks will also die off of skin cancer. So I think you better start considering homosexualism.

	14-12-2003 00:01									#62
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We can KIDNAP the chicks and make them stay indoors

	14-12-2003 02:30									#63
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quote: Originally posted by MrWhereItsAt Heh. If it was on the Discovery channel then I saw the same programme. But I can claim to have some more knowledge from a few Honours level Physics papers in Geomagnetism. This change is NEVER instantaneous, unless you count a few hundred - thousand years as immediate. At the current rate we have several tens of thousands of years before there is any real risk of extra cosmic radiation at ground level. And we are 'overdue' by several hundred thousand years (the average time between reversals has been 200,000 years, we have gone 700,000 since the last one) for a reversal in the same way Wellington is 'overdue' for a magnitude 8.0 earthquake. * MrWhereItsAt wishes he knew what actually gave rise to the 'secular' variations in magnetic fielde strength...

What causes it? Solar Flares?

	14-12-2003 03:02									#64
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maybe this has something to do with the 'rise' in temperatures. ie, another possible explanation for 'global warming'

	14-12-2003 03:51									#65
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The Andy Man, I find it more than interesting that the reduction in the magnetic field coincides with end of mini ice age.

During the recent spate of solar flares, news reports showed just how those flares impacted the Earth's magnetic field. The flares would counteract the field, reducing it. This has got to act as a drag on our core's rotation in some fashion.

However, a reduction in the field does not explain why the magnetic field flips. It would be interesting to see what the causation theories are rather than just note that the flips occur. For example, can the effect be reproduced in computer models?

It just seems to me that the cause of the flip must be some force acting on the core external to the earth. It also seems to me that the most likely candidate for the source of the influence is the sun.

	14-12-2003 04:27									#66
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so... when do I get my super-powers?

	14-12-2003 04:38									#67
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quote: Originally posted by Smiley So is it this decrease in magfield strength that explains the rise in cancer rates, or is that smog really that bad?

I thought it was all the nuclear testing.

	14-12-2003 05:51									#68
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What causes it? Solar Flares? [/QUOTE]

What causes what? If you mean the cosmic radiation, then that is from the flares from the sun, yes.

	14-12-2003 05:53									#69
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Frozzy, no, what causes he reduction in magnetic field strength?

	14-12-2003 05:56									#70
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The liquid core changes the direction of the electric current, so instead of going north to south, it goes south to north. This takes a very very long time. It has to weaken the strength of current before it can change the direction.

	14-12-2003 06:29									#71
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Frozzy, is this phenomenon entirely self-contained or is it influenced or induced externally to the Earth?

	14-12-2003 06:31									#72
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Just as an example of what I mean, the Earth's axis of rotation itself rotates 360 degrees as we traverse around the galaxy. This implies a conservation of momentum on a galatic scale. Could something similar be happening to the Earth's core in response to solar or galatic fields?

	14-12-2003 06:37									#73
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quote: The Andy Man, I find it more than interesting that the reduction in the magnetic field coincides with end of mini ice age.

Didn't someone already point out that this was mere coincidence, as it wasn't until that point that we started measuring the phenomenon in the first place?

	14-12-2003 07:22									#74
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Skywalker, oh. We have no magnetic field data prior to 1845?

	14-12-2003 08:14									#75
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We do, actually.

Take ancient pots or Hawaiian lava for example. When rock cool quickly, they are magnatised according to the status of the magnetic field. Samples of lava in Hawaii from ~ 750,000 years ago have an alignment of anywhere between south, east, north east, north west. Those of ~1,000,000 years ago are south aligned.

	14-12-2003 09:08									#76
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I saw a special on this, and during the reversal there isn't that much increase in radiation according to it (slight increase in cancer rates, for example).

But there will be Aurora in areas outside of the poles, like over London, etc.

	14-12-2003 09:14									#77
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Between this and the sun blowing up, how am I supposed to get any sleep?

	14-12-2003 09:14									#78
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quote: Originally posted by Ned Skywalker, oh. We have no magnetic field data prior to 1845?

I don't know. I just mentioned that another poster said we didn't

	14-12-2003 09:21									#79
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Yes, all data goes back only to 1845 when the Hall of Magnetic Field Data was mysteriously incinerated from above somehow.

	14-12-2003 13:28									#80
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quote: Originally posted by November Adam Maybe we'll go back to sleep?

Back?

	14-12-2003 13:33									#81
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Perhaps it is weakening because we are using too many magnets in everything. Time for a Kyoto Magnet Treaty.

	14-12-2003 13:54									#82
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quote: Originally posted by skywalker I don't know. I just mentioned that another poster said we didn't

Actually, if we do not have data prior to 1845, we may not know what the maximum field is. We might be far below the 90% of maximum that the story suggested.

	14-12-2003 15:15									#83
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quote: Originally posted by Ned Frozzy, is this phenomenon entirely self-contained or is it influenced or induced externally to the Earth?

Depends on what exactly causes the geomagnetic fiedl in the first place. Keep in mind that is is pure supposition that rotation of magnetic liquids inside the Earth is the cause of geomagnetism. There has been a model or two made using computers that shows reversals in magnetic polarity, but there is no way we can really do any experimental tests on something around 2500km deep.

The way the models show reversals is because of a complex rearrangement of circulation fields within the molten outer core. You couldn't just say for instance that the outer core slows and reverses flow direction. It may do, but this would be no easy process! Perhaps there are multiple layers with differing flow strengths and directions, and the interaction between these two (which gets increasingly more complex to model) leads to the flux of the geomagnetic field. Some solid Earth scientists are starting to believe in just such a dual-layer outer core model, but again, this is all just guesswork with computer simulations thrown in.

	15-12-2003 00:15									#84
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quote: Originally posted by MrWhereItsAt Depends on what exactly causes the geomagnetic fiedl in the first place. Keep in mind that is is pure supposition that rotation of magnetic liquids inside the Earth is the cause of geomagnetism. There has been a model or two made using computers that shows reversals in magnetic polarity, but there is no way we can really do any experimental tests on something around 2500km deep. The way the models show reversals is because of a complex rearrangement of circulation fields within the molten outer core. You couldn't just say for instance that the outer core slows and reverses flow direction. It may do, but this would be no easy process! Perhaps there are multiple layers with differing flow strengths and directions, and the interaction between these two (which gets increasingly more complex to model) leads to the flux of the geomagnetic field. Some solid Earth scientists are starting to believe in just such a dual-layer outer core model, but again, this is all just guesswork with computer simulations thrown in.

Could this be a conservation of momentum issue? The magnetic field is a byproduct of currents of molten iron whose flow may be precessing to conserve momentum in some sort of environment. Since the period seems to be in the 100s of thousand of years, this suggests that the momentum that is being balanced is the solar system, does it not?

	15-12-2003 02:37									#85
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MOFG WE ARE ALL GONA DIE, WE MUST VGIVE MORE TAX CUTS AND PASS THE MAGNETIC PROTECTION PATRIOT ACT GIVING BUSH THE POWER TO HAVE SWEX WITH ALL NEWLY WED WOMENA!

	15-12-2003 03:34									#86
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my this is bad news.

I dunno about you guys, but i plan to live for quite a long time.... Im very concerned now...


I dont wanna die young!

	15-12-2003 03:37									#87
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quote: Originally posted by Sava PASS THE MAGNETIC PROTECTION PATRIOT ACT GIVING BUSH THE POWER TO HAVE SWEX WITH ALL NEWLY WED WOMENA!

is this because bush has a gene to survive all the radiation and therby allowing the future generation of humanity to inherit this magnificent ability!????

brilliant!

	15-12-2003 03:51									#88
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quote: Originally posted by MrWhereItsAt Depends on what exactly causes the geomagnetic fiedl in the first place. Keep in mind that is is pure supposition that rotation of magnetic liquids inside the Earth is the cause of geomagnetism. There has been a model or two made using computers that shows reversals in magnetic polarity, but there is no way we can really do any experimental tests on something around 2500km deep. The way the models show reversals is because of a complex rearrangement of circulation fields within the molten outer core. You couldn't just say for instance that the outer core slows and reverses flow direction. It may do, but this would be no easy process! Perhaps there are multiple layers with differing flow strengths and directions, and the interaction between these two (which gets increasingly more complex to model) leads to the flux of the geomagnetic field. Some solid Earth scientists are starting to believe in just such a dual-layer outer core model, but again, this is all just guesswork with computer simulations thrown in.

I remember several Discover articles about a theory that it the core wasn't, in fact, nickel-iron. Rather, the guy thought it was uranium and the field was caused by its radioactive decay. The article said this accounted for the reversals too (I'm not sure how).

	15-12-2003 07:07									#89
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Hmm, magnetic field starting to collapse around 1840's.
Marx and Engels start to develop what would later be known as socialism/communism around the 1840's.
Conclusion: Commies cause Magnetic problems.
Solution: Throw all commies out of helicopters, no more magnetic problems.
Benefits: No more magnetic declenation

	15-12-2003 07:25									#90
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quote: Originally posted by Ned Could this be a conservation of momentum issue? The magnetic field is a byproduct of currents of molten iron whose flow may be precessing to conserve momentum in some sort of environment. Since the period seems to be in the 100s of thousand of years, this suggests that the momentum that is being balanced is the solar system, does it not?

I don't know how the Earth's magnetic field is supposed to flip but I do know how it supposedly happens in the sun's life cycles, and I'd imagine its a similar process on Earth.

Simply put, the sun's core is made up of several layers that rotate at differing speeds at differing latitudes and altitudes, each layer creating a different strength and orientation of magnetic field in each part of the sun. Effectively these fields superimpose upon each other and produce the external Heliospheric magnetic field that we can measure. Over time the alignments of these field changes, tightening and stretching the field strength to a maximum (visually the field lines look like the wringing of a towel tighter and tighter). Once a maximum is reached the field strength weakens again as the various magnetic fields of each part of the sun realign, and then eventually begin to unalign in the opposite direction.

There is no changing in direction of the flow or speed/momentum of the various parts of the sun though, just as there is no change in the rotation or motion of the Earth as it passes through the seasons from Spring to the the Summer (maximum) and then back trhough Autumn to the Winter (minimum). The solar cycle lasts for 11 years and is very regular.

At a guess the Earth's magnetic cycle is an erratic copy of the suns.