I recently read that the earth's magnetic pole is shifting quite rapidly now, and soon won't even be in Canada anymore. (Another Canadian resource gone forever! Sob!) Does anyone know why its rate of shift changes?
Posts: 6538 | Location: British Columbia, Canada | Registered: 06-11-02
The earth’s magnetic poles have reversed many times over the earths lifetime. It has also been proved that there were great extinctions in the animal kingdom just after these events. It is thought that we are due another reversal any time now and that civilisation is at risk due to our heavy dependence on electronics. Have a look at this.
http://www.ucl.ac.uk *************************************************** 06-14-02, 09:10 PM MilesWest Thank you for the excellent and very informative link ikidunot, however I must comment on your statements.
It is true that the earth's magnetic field has reversed many times in the past, but major extinctions have been associated with only two: One which occured 65 million years ago and another about 250 million years ago, and neither of the mass extinctions have been "proven" to be caused directly by the reversals.
The risk to civilization is not due to our dependence on electronics because most electrical devices work by generating their own magnetic fields and are not effected by that of the earth's. The potential danger to civilization and indeed life itself is from the loss of the magnetoshere in the upper atmosphere which acts as a shield to the earth's bombardment by the high energy particles from the sun. As to babthrower's question:
Does anyone know why its (the north magnetic poles) rate of shift changes?
The short answer is: Not really.
Although ikidunot's linked thesis presents some great and quite feasable theories on the dynamics of the earth's magnetic field no one knows for sure.
Linda Moulton Howe of Earthfiles reports:
Now a science team from Paris, France led by Gauthier Hulot at the Institute of Earth Sciences in Paris - working with other scientists such as Harvard University's magnetic field expert, Dr. Jeremy Bloxham - have compared satellite measurements of the earth's magnetic field strengths 25 years ago and today. Their discovery was published in the April 2002 science journal Nature and it boils down to this:
"There are strange and not very well understood variations now in the earth's magnetic field."
In fact, according to new satellite data, down in South Africa there is a large region that already has a magnetic field pointing in the opposite direction from the rest of the earth's field and it is getting stronger all the time.
quote:Originally posted by ikidunot: Notice the current social and political unrest everywhere in the world, while the largest explosions ever recorded in the solar system have recently occurred on the surface of the sun.
06-15-02, 02:13 PM ikidunot A winks as good as a nod to a blind horse EH? wink Relax don't sweat the small stuff. big grin 06-23-02, 05:31 PM Matiqua Check out the topic about a theory on extinction 65 000 000 years ago that I wrote.
06-28-02, 07:12 PM mahal Actually, the earth's magnetic signature is constant and very predictable (unless you're talking about a "very rapid change" on a cosmic time scale. wink
US Navy ships have developed a degausing system made up of a series of metal elements built into the ships' frames. They're hooked up to a digital system loaded with a "map" of the magnetic lines of force over the earth's surface.
The system was developed to counter the threat of magnetic mines. Magnetic mines are designed to sense a change in the earth's magnetic signature whenever a large metal object (like a ship) breaks across a magnetic line causing a local difference of potential.
The degausing system reads the ship's movements, reads from the software and determines the necessary level and location of current to pass through the ship's hull to cause the ship to leave a null signature as it moves.
IKIDUNOT: Sunspots only have a very minor effect on electromagnetic waves and negligible (if any) on electronic equipment. The greatest influence on radio waves in the atmosphere is the sun's ionizing of the atmosphere, and this effect is predictable and not a problem so much as an inconvenience. (The ionosphere during the day won't allow certain frequencies to pass through. Solution: satellites use higher, unaffected frequencies.)
Not only do electronic devices use their own voltage sources and magnetic fields, they are also grounded and shielded from outside interference.
Examples:
Your computer may have a plastic case, but it has a metal one inside, as well as a common grounding and voltage/current protection circuits built in. Some of the components on the circuit boards (IC's in particular) burn up with as little as 20 volts induced on a pin. When you rub your feet on the carpet, your own finger can produce as much as 8-10,000 volts (if you can see the spark, it's around 10,000). On a work bench, when you have your computer taken apart, you should wear a wrist strap (ESD strap) tied to a ground source to drain the voltage potential that develops in your hands because you may be disengaging some of the protective circuits or making contact with the chips directly.
The military has dabbled in "nuclear hardening", meaning that essential equipment has been encased in such a way as to protect it from the electromagnetic disturbance created by a nuclear detonation. The crew would be dead, but the radios would work!
[This message was edited by mahal on 06-28-02 at 07:27 PM.]
06-29-02, 10:08 AM ikidunot Thanks mahal, However I am a little confused.Have a look at the following.........................................
When magnetic fields move about in the vicinity of a conductor such as a wire, an electric current is induced into the conductor. This happens on a grand scale during geomagnetic storms. Power companies transmit alternating current to their customers via long transmission lines. The nearly direct currents induced in these lines from geomagnetic storms are harmful to electrical transmission equipment. On March 13, 1989, in Montreal, Quebec, 6 million people were without commercial electric power for 9 hours as a result of a huge geomagnetic storm. Some areas in the northeastern U.S. and in Sweden also lost power. By receiving geomagnetic storm alerts and warnings, power companies can minimize damage and power outages. ...................ALSO...........................
One to four days after a flare or eruptive prominence occurs, a slower cloud of solar material and magnetic fields reaches Earth, buffeting the magnetosphere and resulting in a geomagnetic storm. These storms are extraordinary variations in Earth's surface magnetic field. During a geomagnetic storm, portions of the solar wind's energy is transferred to the magnetosphere, causing Earth's magnetic field to change rapidly in direction and intensity and energize the particle populations within it.
One of the problems in the search for a mechanism at the root of polarity reversal is that no one reversal seems to occur in exactly the same way. Records of magnetic elements (dip, declination, and intensity) that span reversals are relatively hard to come by, being found in sedimentary cores and in large magnetic intrusions; the Tatoosh intrusion in Mount Rainier national park is one specific example of a location that has recorded a magnetic reversal. Palaeointensity studies of these reversal records indicate that the field intensity usually drops to about 1/10th of its normal value a few thousand years prior to the reversal, and does not return to its original intensity for several thousands of years after. In all, the total duration of the majority of reversals is of the order of 10E4 years, though there are exceptions in which the polarity reversed either without a reduction in field intensity, or reversed very quickly (within a few hundred years).
06-29-02, 03:44 PM mahal I'm not sure, but I think magnetic storms are limited to the atmosphere, and as such, their magnetic affects would disperse quickly. Many different wires and cables (like the BNC type you get from your cable company) are protected by shielding under the insulation, so they wouldn't be in any danger.
I'll be the first to admit that power companies don't deliver clean power. Where I live, the (infrequent) power spikes can wreak havoc on our equipment, and we've been forced to install filters in line. My experience is in electronics more than electricity (meaning I do circuit boards, not power poles). big grin
06-29-02, 07:11 PM ikidunot Hi mahal What i'm trying to say is if the top brains of the western world (North America) have given their best and this can happen perhaps we should start worrying.Thanks mate................Pat.
07-01-02, 03:08 PM mahal Babthrower:
It seems to me that the overall magnetic characteristics of the earth would be determined by ferrous metals underground (like iron), since they are what determine polarity and strength of the fields, the same as an electromagnet. (In an electromagnet, you can increase the strength of fields 3 ways: by increasing current through the windings of the wire around the core, by increasing the number of windings, or by increasing the amount of iron in the center.)
Since 1) the amount and distribution of iron and other metals in the earth is fixed (except for mining and volcanic activity), 2) the only current induced would be from atmospheric disturbance, and 3) the number of "windings" is fixed in the bioshpere, such as in volume of sea water, the magnetic field should be stable on the inside and only temporarily fluctuate in the atmosphere.
Regardless of the source of the disturbance, the polarity should never change, therefore the direction of the magnetic fields (both the H and E fields) should never change. So if they are changing, the source must be minute shifts in metals from underground activity.
07-02-02, 04:35 PM mahal Interesting article, ikidunot, thanks. If the theory is correct, then three things have to be true:
1) The solid iron core would act as if it were the stationary core of an inductor, and the molten iron would act as the catalyst of inducing current
2) Both the solid and molten iron would have to have magnetic fields of their own, otherwise no current could be induced when their fields crossed.
3) A shift in the earth's magnetic poles would have to have been caused by a 180 degree reversal of the "whirlpool's" direction of flow. If the direction of flow is caused by the earth's rotation, then this also would have had to have been opposite in the past.
One thing I noticed about the article is that proof of the shift comes from rocks bearing the evidence of a magnetic signature in the past. The article seems to jump to the conclusion that the rate of shift is not constant, but that must be based on the assumption that our geologic record is complete, and that we are fully aware of every shift.
That's probably not the case; we probably only know of some shifts.
If the induction being discussed in ikidunot's article above causes alternating current, then we should expect a reversal of poles twice in each full cycle, and the reversal would be as regular as clockwork, even though the frequency of change may be very slow.
07-05-02, 09:48 AM chanceygardner Maybe are interested in this....
07-05-02, 10:16 AM ikidunot Thanks chancey I think that the second link says it all......................................Pat.
07-05-02, 12:27 PM babthrower Can you imagine the impact that would cause the earth's rotation to reverse? (I can't imagine anything except an impact to cause this reversal.) The momentum of the rotation would be immense! Like a baseball, the pitcher puts a spin on it, the bat connects, the spin might be reversed as it caroms away. But what an impact!
Maybe there was once a huge rocky-iron inner planet that was completely smashed into 3 or 4 main planets. Some of the surviving material might change rotation once it/they resumed their (vastly changed) path round the sun.
It boggles the mind.
07-06-02, 05:42 PM anguilla Uh...anybody remember that an asteroid or comet hit what's now Yucatan about 65 million years ago?
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