For the first time, it seems Cecil got it wrong. The disaster that Noone mentions is that the Earth is going to shift 90 degrees from its axis. Of course this would cause major catastrophes (Velikovsky style). This is nonsense. This would mean that its poles (places where the rotation axis touches the surface of the Earth) would move from place, with the Earth leaning.
The shifting of the poles that the question refers are the MAGNETIC poles which have move and switched polarity from time to time. This magnetic poles have “spiralled erratically toward their present location”, not the natural (astronomical) poles.
I read the question twice and I can’t really tell which kind of pole-shift the questioner is asking about. “Periodic rotation of the poles” implies the flipping of the magnetic field mentioned above … but I can’t figure out why this would destroy civilization or hurt TV reception or anything. It would make magnetic compasses pretty useless for a while until we got used to the new direction the needle was pointing. Would this make planes crash? I don’t think so … I think planes these days rely mainly on gyro compasses, GPSs, and reception from VOR stations, but y’all pilots can correct me if I’m wrong.
But yes, I agree that I wish Cecil had given us the SD on the periodic 180 degree shift in “magnetic north”, and not just focussed on the predicted 90 degree shift in “true north”.
While it is true many Poles were once located in the northern part of the Soviet Union I think current Japanese & Canadian immigration laws would not allow the shifiting of Poles 90 degrees in either direction.
The problem with the shifting of the earth’s magnetic poles I believe is related to the time in the middle when there is little or no net magnetic field to the earth. In addition to disrupting magnetic compases, a non-trivial problem, it would also interfere with charged particles in the atmosphere (the ionosphere or the Van Allen belts or something like that) that protect us from solar radiation. This would supposedly allow lethal levels charged particles from the sun to reach the surface. I have no idea if this is true, but even if lethal levels did not reach the surface I suppose broadcast TV, radios, etc. would be pretty useless. I do not recall how often the earth’s magnetic poles switch, but I do remember reading about scientists studying this with magnetic rocks from core samples.
The charged particles trapped in the uppermost atmosphere (called the “ionisphere” because ions are a type of charged particle) don’t protect us from solar radiation; they are in fact the very problem that the Earth’s magnetic field protects us from. The Earth’s magnetic field traps high-energy changed particles, originating from both the solar “wind” and the so-called “cosmic rays”, so that they circulate around the Earth and eventually smack harmlessly into our atmosphere at a shallow angle near the magnetic poles – thus giving rise to the Aurora Borealis and Aurora Australis.
The temporary lack of a magnetic field during a Polar Flop would mean all these particles would just come smashing straight down from deep space in all directions. There would be no Aurora Borealis/Australis or Van Allen belts during this time, we’d just get more-or-less cooked instead.
From what I remember reading in one paleontology book, these magnetic reversals happen every 20-30 million years or so.
Quick-N-Dirty Aviation: Trading altitude for airspeed since 1992.
Why would we get cooked by a bunch of ions? Unless there is some sudden discharge like a lightning bolt ions are pretty harmless… once they’re dispersed anyway, which they should do on their own since they repel each other.
The big dangers from outer space are gamma rays, UV rays and martian grad students doing theses on bovine surgery.
Possibly you have some psychic bond that enables you to know what the questioner had on his mind, areynaldos, but I don’t. My guess was that he had heard something about periodic reversals of the earth’s magnetic polarity and conflated this with then-current scare stories about a shift in the earth’s axis of rotation. Geologist Jean Andrews, who speculated about the spiraling of the poles, was talking about a shift in the rotational axis, not the magnetic poles.
Cecil: When you talked about the poles moving in spiral is exactly what really happens with the magnetic poles. I didn’t think of it as the true poles shifting slowly, which would mean that the Earth moves tilting in its orbit… I think the question was mixing the two ideas (magnetic poles moving and the Earth changing its axis of rotation). Of course I have no psychic powers to know the questioner’s mind, nor yours by the way!
Maybe as you mention all these “theories” come from the confussion between the two ideas. By the way, what happens when the polarity of the Earth poles change? Interesting question some people has already mentioned.
I don’t have any psychic powers either but remember psychic Silvia Brown (who have solved many missing person cases along w/ other supernatural stuff). have predicted want she calls a polar tilt. She claims it has started and will continue to mess w/ weather paterns. She regularly appears on the Montel Willams show.
No one here is saying there is anything like psychic powers. I thought “Cecilians” had a little more sense of humor or at least could understand a sarchastic comment (that came from Cecil, BTW).
Th psychic chick can call it whatever she wants. However, there is a phenomenon that I believe is called “polar wobble.” Earth doesn’t spin precisely on its axis, since there isn’t actually a stick running through the planet on which we revolve. There is a pattern of shifting axial tilt that varies weather patterns somewhat over a long period. It’s a gyroscopic thing.
Of course, I have no documentation to back myself up, and I don’t remember how long the period is – it could be as short as 20 or as long as 200 years.
Your last reply still begs the question(s): what of significance (if anything) would happen if the earth’s magnetic poles shifted, passing through a period of no net magnetic field? Has this happened in the past? When? Is it likely to happen again in the near future?
The magnetic poles do shift continuously in relation to true north. Maps that have lines of magnetic variation have to be updated periodically because the numbers change.
In aviation, a runway’s number represents the direction the runway is pointing relative to magnetic north. Thus, if you were landing your plane on runway 29, the compass would read 290 degrees. Here in Edmonton, we had a runway 29, and a lounge just across the street was called “Runway 29”. About five years ago, runway 29 became runway 30, because of a change in magnetic variance.
The physical tilt of the rotating Earth also varies due to gyroscopic precession.
There are two “wobbles”. One, precession, is a longish cycle of 20-something thousand years. The other, nutation, is much smaller, and follows a cycle of only 19 years.
But these “wobbles” involve the entire earth, not just the poles. Consider a globe, mounted, as most globes are, at a tilt. Place the globe and its base on a turntable, at the center. Spin the globe, and slowly turn the turntable at the same time. There you have rotation and precession. (Nutation is not different in kind from precession, but it would be more difficult to construct a model with three movements.)
None of this has to do with the hypothetical physical shift in the axis, which would, in our model, entail ripping the physical axis out of our globe and ramming it through from another angle.
That, for what it’s worth, is most definitely not happening “already”. The south-pole research station keeps very careful track of where the pole is, because the Antarctic ice shifts over it, and they have to move the marker every year, since it’s on the ice. But the pole itself is in the same place. (If it were shifting, every astronomer on Earth would see it immediately.)
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