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False North

Map Alignment Protractor
  (+11, -7)
(+11, -7)
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against]

There's a good chance that in the next 100* years or so the North Pole may be down near Australia.

Some cats, dolphins and pigeons may be confused by this.

All our maps will be wrong, their grid and Magnetic North calibration lines will be wrong, but with the False North Protractor, we'll be OK.

The idea is to produce a protractor with a movable calibration line on it, which can be adjusted to where Magnetic North is with relation to where it was when the map was printed, as well as any local magnetic perturbations. Then it can be aligned with the "Magnetic North" line of maps to provide a mapping to where the map really refers to.

(* I guessed the 100 years bit, but I'm told by the other voices in my head that it's quite possible.)

Dub, Jan 01 2006

BBC NEWS - Magnetic north pole drifting fast http://news.bbc.co..../nature/4520982.stm
[Dub, Jan 01 2006]

Geomagnetic reversal http://en.wikipedia...eomagnetic_reversal
[Dub, Jan 02 2006]

magnetic north lies on antarctica http://en.wikipedia.../wiki/Magnetic_pole
In your face [zeno, Jan 02 2006]

Timeline of Earth's magnetic polarity http://www.pbs.org/...netic/timeline.html
[Dub, Jan 29 2006]

Magnetic Field Reversal Article http://news.nationa...927_field_flip.html
This was in National Geographic a while ago. [neutrinos_shadow, Jan 30 2006]

Where the Earth's magnetic field comes from? http://scienceblogs...s_magnetic_fiel.php
[Dub, Mar 10 2008]

Sun's likely to flip soon http://news.nationa...rsal-space-weather/
[Dub, Aug 07 2013]

[link]






       Magnetic north never matched up with geographical north even in the earliest days of cartography. Why should anyone care now?
Aq_Bi, Jan 01 2006
  

       Even if the poles did begin to switch right now, it could take over a thousand years for them to come back to a comparitive rest in their new positions.
fridge duck, Jan 01 2006
  

       When floated in a bath, do [fridge duck]s spin clockwise or counterclockwise at present?
ConsulFlaminicus, Jan 02 2006
  

       //Magnetic north never matched up with geographical north even in the earliest days of cartography. Why should anyone care now?\\   

       AHUMAHUM The magnetic north is on Antarctica AHUMAHUM
zeno, Jan 02 2006
  

       A-wimowe a-wimowe, really?, a-wimowe a-wimowe
Ian Tindale, Jan 02 2006
  

       who woke the lion?
po, Jan 02 2006
  

       oompa loompa hoompidi doompa yes oompa loompa hoompidi doompa
zeno, Jan 02 2006
  

       So, pretty soon it'll be Magnetic East?
Ian Tindale, Jan 02 2006
  

       A + for the source of inspiration.
ldischler, Jan 02 2006
  

       [Ian], once it gets that far, the whole geodynamo will go totally wonky (that's the scientific term) and as [fridge duck] said, we'll have an extended period of basically random magnetic fields over the entire planet.   

       It's actally a major ecological disaster when it happens, the amount of solar radiation hitting the earth is vastly increased during these periods.
5th Earth, Jan 02 2006
  

       [UnaBubba]There was talk of it suddenly flipping South.
Dub, Jan 02 2006
  

       How about defining the poles of the Earth in terms of the places where, if a Mercator projection is made of the globe, the poorest countries look biggest?
What would happen to the time zones in this scenario? Wouldn't they cease to correspond to the rotation of the planet? Might this not be a good thing?
If a gyrocompass were used, the magnetic poles would not matter from the viewpoint of navigation.
nineteenthly, Jan 02 2006
  

       //What would happen to the time zones in this scenario? // - Erm, nothing? They wouldn't actually become bigger... and the Earth wouldn't rotate any faster.   

       //If a gyrocompass were used,// Would non-uniform gravity affect one of them?
Dub, Jan 02 2006
  

       First of all, printed on aeronautical charts there is the agonic line (which is the line of zero magnetic variation) and various isogonic lines (which show the degrees in East or West variation).   

       Since the magnetic north pole is in north central Canada, the variations in the Pacific northwest are enormous -- greater the 20 degrees in southern Alaska for instance. For navigation, it doesn't really matter where the magnetic pole is as long as the variation is know for the location you're in.   

       When I started taking flying lessons as a kid, the airport I used (in the late 1970's) was on the agonic line. Today, it's around 4 degrees west variation.   

       Runway numbers are based on the rounded off magnetic course of the runway (i.e. Runway 22 is aligned between 216 and 224 magnetic course). As a result, airports may have to change the numbers on some of the runways every few decades.   

       [UB], The magnetic pole really does move quite rapidly. It's MUCH more than a few inches a year. In fact, it's probably a few feet per day.   

       Although I don't really get the protractor idea here because the correction lines are already printed on any navigation chart that would be relevant, I'm giving it a toasty bun just for the link. [+]
zigness, Jan 02 2006
  

       //There's a good chance that in the next 100* years or so the North Pole may be down near Australia. //   

       Not so.   

       What will happen is that the magnetic field will diminish to nothing and then re-emerge a few thousand years later near the south pole.   

       That was covered in the associated articles with your link. Click on some of the "see also" items to check.
zigness, Jan 02 2006
  

       //The Earth's current geographic north is thus actually its magnetic south. Confounding the situation further, it is known that the Earth's magnetic field has reversed itself in the past, so this system of naming is likely to be backward at some time in the future (see Earth's magnetic field). \\   

       Taken from link, thought it was common knowledge, maybe it is and some have been ignoring me.
zeno, Jan 02 2006
  

       What i meant about the time zones is that at present, they radiate from the poles of the Earth, i.e. where the axis of rotation intersects with the surface. If the poles were defined as in a different place, the time zones might radiate from these poles instead. This would clearly be silly, but in that case, surely there would still be a sense in which the poles would still be where the axis of rotation is.
There is also the question of latitude and longitude, which would then be defined with respect to different poles and a different equator. However, i realise that the magnetic pole is not currently used for any of this.
I don't think a gyrocompass would be affected by anything less than real extremes of gravity, but this is just a hunch, i can't justify it.
A map for which North and South were in a different place than where they now are would be distorted in a different way than a current map projection. On Ordnance Survey maps of the UK, and therefore i suppose local maps in other parts of the world, the direction of north is not the same as either true north or magnetic north in any case. I would think this would be outdated by GPS, except that in a situation where the magnetic field has decayed, as will probably happen at some point in the next few centuries, all that sort of equipment will probably be fried, so something like this could be needed, but i don't think a protractor would be enough.
nineteenthly, Jan 02 2006
  

       //direction of north is not the same as either true north or magnetic north in any case// What are you talking about?
zigness, Jan 03 2006
  

       I've never had success with a compass anyway. I find there's always enough stiction in the mechanism that with a little bit of shaking, I can get the needle to point any direction I want, even due South. It's bad enough that, for myself, it is impossible to determine conclusively which way is which.   

       But I do know which way is up, and living in the Northern hemisphere I know the sun is always in the South, and I've heard that the concave side of the waning moon faces East. Or is it West? Now I can't remember...
Grunchy, Jan 03 2006
  

       I very much doubt the 100 years bit. We've been using compass navigation for a good few centuries without too much of a problem. OS maps in the UK already provide a Mag north/grid north correction.   

       Zeno's wikipedia link I find a little surprising. I learned at school that the magnetic North of the Earth was a north pole and that the end of a magnet was a 'North-seeking' pole, confusingly abbrevited to a north pole. I suppose you could call the North pole of the Earth a South-seeking pole and abbreviate it to 'South', but I think that would be stretching a point. Maybe there's a reason he's called zeno.
st3f, Jan 03 2006
  

       if the earth's magnetic pole switches end every so often, are we in a south end term at present?
po, Jan 03 2006
  

       [Grunchy] The sun is NOT always in the south in the northern hemisphere. It is at noon, but not sunrise or sunset... very far north, and the sun pretty much rises and sets in the north around the summer solstice.
zigness, Jan 03 2006
  

       [zigness], north as shown on an Ordnance Survey map in the UK is the direction of the vertical grid lines, which do not necessarily point towards the north pole because of the projection used on these maps. The central vertical line points north, but the further from this line a vertical grid line is, the further it deviates from pointing towards the north pole. This is known as grid north. I think this is also true of other maps of this kind.
However, there's always Polaris.
nineteenthly, Jan 03 2006
  

       I'm fairly sure this is all just an evil plot dreamed up by the Australians to rule the world.
Worldgineer, Jan 03 2006
  

       <imagines Aussie remake of Karen Carpenter's "I'm on the top of the world">
lurch, Jan 03 2006
  

       //I'm fairly sure this is all just an evil plot dreamed up by the Australians to rule the world.// even *with* UB they are doomed to failure.
po, Jan 03 2006
  

       {Notices the commotion, and quietly leaves through a hidden door below the [logout] link}
Dub, Jan 03 2006
  

       take care, there is a secret *delete my account* link there...
po, Jan 03 2006
  

       {secretly deletes po's account}
Ian Tindale, Jan 03 2006
  

       Back to the idea...
//Some cats, dolphins and pigeons may be confused by this.//
I think a special recalibrated compass should be fitted to them. Of course, they should be given the appropriate training.
Ling, Jan 03 2006
  

       Maybe thats how the dinosaurs died. They probably got confused, went the wrong way home and starved.
Jscotty, Jan 29 2006
  

       What, all the dinosaurs accidentally swam up the Thames one day?
Ian Tindale, Jan 29 2006
  

       just maybe...
Slaith, Jan 30 2006
  

       I wouldn't think a gyrocompas could consistently point anywhere but at the earth's rotational north and south poles. Were it oriented in any other way, the part of the earth toward which it pointed would move as the earth rotated and the compass did not.
supercat, Jan 30 2006
  

       If this did happen in 100 years, would it matter anyways? Everyone is talking about Global Warming, and how the Arctic poles are slowly melting. So if this does happen in 100 years, and so has global warming... will there even be a north pole for this invention to actually work?
adf13, Jan 31 2008
  

       Everyone knows that magnetic north is not geographic north.... sorry for the reiteration.
Antegrity, Feb 02 2008
  

       Except for Peter North.
normzone, Feb 03 2008
  

       Will this make water go down the plugholes the wrong way too?
And if the Southern Hemisphere suddenly becomes the Northern Hemisphere, will all the penguins immediately migrate?
coprocephalous, Feb 03 2008
  

       Many higher end compasses include a declination adjustment to allow them to compensate for magnetic north and they work very much as you have described.
jhomrighaus, Feb 03 2008
  

       [copro] No. Maybe.
Worldgineer, Feb 04 2008
  

       Despite many hesitations, I'm still going to post this:   

       1) Ice is not a requirement in the definition of any kind of pole.   

       2) The earth will still continue to rotate on (about) the same axis no matter where the magnetic poles are.   

       Most people here seemed to already get these two points. Some didn't, sorry for the interruption.
drememynd, Feb 06 2008
  

       Can I just also point out that there's no //major ecological catastrophe// consequent on this? Tops, we're looking at an 8% increase in the incidence of skin cancer when the mag field goes quiet, as the Van Allen radiation belts would collapse. Temporarily, until the new magnetic poles assert themselves.   

       Must be true, Discovery Channel wouldn't lie.   

       In the same documentary, they mapped the last 300 years of British Admiralty records of magnetic deviation, and animated it. You could see the chaotic fluctuations in the field accelerating. Yes, we're due for a magnetic pole reversal sometime soon(ish); in fact you could already see the probable new pole emerging in the southern Indian Ocean.   

       But yup, no big flippy turny Earth topsy turvy end-times cosmic hoo-haa.
BunsenHoneydew, Mar 12 2008
  

       Is anyone around to tell us what happened last time?
Dub, Jul 05 2008
  

       //But yup, no big flippy turny Earth topsy turvy end-times cosmic hoo-haa.// That wants setting to music.
pertinax, Jul 05 2008
  

       Well, there is a pole switch song, by killing joke.   

       Anyway, why isn't this some kind of decoy, with lots of people in flat caps, with lots of whippets and black pudding?   

       Probably best placed somewhere near Watford, for ease of travelling.
not_morrison_rm, Aug 08 2013
  

       Actually, if the new pole ended up at the Watford Gap, there wouldn't be a 'North of the Watford Gap'. Everyone else in the UK would be a Southern Bastard.
Ling, Aug 08 2013
  

       I thought that was "southern jessies"?   

       What happens if north pole ends up in South Korea? Imagine them all having to swap the flags, re-do the letterheads etc.
not_morrison_rm, Aug 10 2013
  
      
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