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North Pole is Leaving Canada
Dedekind writes: "CNN.com is posting this story
on the drifting of the Magnetic North Pole. Not only is the pole shifting from a spot just North of Resolute,
Canada, Canadian scientists expect it to end up in Siberia within the next half-century. Perhaps the most interesting part of the
story (which really is only a small part at the end) is that many couples like
to go to the magnetic North Pole to conceive their children.
"
15 seconds of Google research will tell you that the pole reversal is thought to take 1000 years or so to complete. So it's not like you'll wake up some morning and magnetic North will suddenly be South.
End of lesson. You may press the button.
This is very old news. The NMP has been known to drift for pretty much as long as there have been compasses. The magnetic declination on topo maps has always been out of date, usually from the moment they've been printed. For example, I've had people tell me that the magnetic declination in the Rocky Mountain Front Range is 17 deg E (based on topos), when in fact it is currently close to 0 (I'm too lazy to look up current coordinates ;-). It may very well have been 17 deg in 1903, but the pole has drifted considerably since then!
The article also makes it clear that the odds are poor that it will actually end up in Siberia, as the pole has never followed a straight line, and the rate of movement has always been unpredictable.
A well-crafted lie appears unquestionable - Dama Mahaleo
The north pole heads north? I don't think that's possible. Seems to me the north pole can only head south, no matter what direction it's going in.
Whoops, guess I should have used the "Preview" button. Corrected post follows:
but if the poles just flipped, imagine what chaos it would cause. Would we have to relabel all the maps that are made?
Aeronautical maps are re-issued every 4-5 years anyway, because of this natural drift. Pick up any aviation chart and look for the curving lines called "deviation lines." These are used by pilots to convert from magnetic heading to true heading. Since the poles move, the lines also move, and the charts are re-printed periodically. This isn't a big deal, since other things change over time too, as new airports are added, and airspace is re-classified.
Incidentally, if the poles flipped, older planes wouldn't have any trouble navigating. All planes have at least a basic instrument navigation system to direct them to fixed radio beacons. Even most older planes are fitted with relatively modern (<10 years old) instrument navigation systems (IFR).
A relatively more significant issue to worry about are the runways themselves. The numbers on the ends of runways are the first two digits of the magnetic heading corresponding to the runway direction. If the poles flipped, these numbers would all have to be updated.
The "chaos" that we'd have to worry about would actually be in relation to the radiation shielding provided by the Earth's magnetic field. If the poles were to switch, it's not the kind of thing that happens instantaneously. It could take years, even decades for the switch to complete, and in the interim, we would be vulnerable to harsh radiation from the Sun. Aside from the obvious effects to our health, this could disrupt power grids and disable magnetic storage media. THAT is what you should be worried about.
Like woodworking? Build your own picture frames.
IIRC, marine charts (what a map's called when you put it on a boat) at least regularly have correction sheets printed, so the charts don't go out of date as quickly.
The difference between magnetic and true north is called declination. Some maps even say how much the declination changes per year. Here is a nice FAQ about declination which includes a section about how to determine declination. More information about declination Here.
also, you can make a compass using a bowl of still water, a blade of grass, and a small sliver of ferrous metal. (like the hand of a watch)
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The magnetic field of the Earth is due to a highly spinning core of liquid ferrous material (the "dynamo effect") - that is, sustained electric currents set up a magnetic field. Pole movement and pole reversal are two different things (and probably completely unrelated to each other). What causes pole reversal isn't very well understood - there're some good theories, but until we know more about the inner structure of the Earth, no good solid evidence (the dynamo effect, it should be noted, isn't well understood either! Mars wasn't supposed to have a magnetic field - no liquid core - and Mercury wasn't supposed to have one either - spinning too slow - but they both do, and Mercury's is quite noticeable) as far as I know.
:) The Earth's period is roughly 250,000 years, and the Sun's is 22, so as you can guess, we have a lot of data about the Sun's, and virtually none about the Earth's. :)
There isn't really a good qualitative description of what's going on, but basically, the core of the Earth is a spinning liquid ferrous object which is highly conducting, and sets up huge currents which produce huge magnetic fields. These magnetic fields can get "trapped" in a convective layer above the core (and become "earthspots", in analogy to "sunspots"). The sunspots act to cancel out the conductive field (the dipole portion) which weakens the field. These perturbations can cause the conductive region to 'flip' to the other polarity (there are two spots of stability, one with + polarity, one with - polarity: if you 'push' the magnetic field enough away from the original, you can shove it to the opposite polarity) which then begins to cause sunspots of its own, and the cycle continues.
The field recovers basically because there are two magnetically generating 'layers' - the core, and the convective region. They, together, cancel each other out, but because the core generates the convective region, the magnetic field is only zero so long as the polarities of the convective region and the core are opposite and equal (which doesn't last 'long' on a cycle scale).
This is all assuming everything works like the Sun does, which is assumed, but not entirely sure.
And in response to the grandparent of this post, good luck hitting any LEO satellite with a missle. That's like trying to shoot a fly at 5000 yards with a .44. Talk about a feat!
Actually, hitting a satellite in orbit was done back in the '80's. Sure, it was by the US Air Force, but I don't think that they have a monopoly on cool weapons tech. ASAT missle
Necessity is the mother of invention.
Laziness is the father.
Original article headline:
North Magnetic Pole could be leaving Canada
Slashdot article headline:
North Pole is leaving Canada