The magnetic north pole is moving...
- Thread starter KellysEye
- Start date
BelleSerene
Well-Known Member
Makes no difference, windvane doesn't look at the compass
You may find that if you use the wind direction to navigate by, you won't always get where you thought you were heading.
GHA
Well-Known Member
Yes you do
Just the heading might be a bit different to the intended passage plan, but as long as the boat's happy it nearly always doesn't matter.
Daydream believer
Well-Known Member
Yes!! but you will do it efficiently
As for magnetic deviation, my compass is so far out of sync with any thing, other than the hand held VHF in my pocket or the metal fuel can in the stern locker that 20 degrees either way is chicken feed.
Standard procedure is to just sail south until the coast of France pops up & then decide where it was I really wanted to go
BelleSerene
Well-Known Member
Perhaps not much has changed, then, since the Vikings just sailed East (because they could maintain a latitude) until the coast of [UK/ North America] popped up and then decided where it was they really wanted to go!
And there we were, thinking it really mattered where the North pole was sitting.
NormanS
Well-Known Member
I think if they had sailed EAST, they would still be looking!
BelleSerene
Well-Known Member
Oops... good spot Norman. Thanks!
lpdsn
Well-Known Member
Bit of a simplistic calculation, but 50km/yr gives 400 years.
AntarcticPilot
Well-Known Member
That's where order of magnitude guesstimates come from - that and arguments from the known resolution of datable sequences such as the magnetic anomaly stripes spreading from mid-oceanic ridges. We have an upper limit imposed by the resolution of datable sequences, and the lower limit is implied by arguments such as yours. However, the rate of change at the moment is much higher than it has been in the past - we've been watching the position of the magnetic poles simce the 19th century; some of the early Arctic and Antarctic expeditions were concerned with locating the magnetic poles.
Incidentally, the position and motion of the magnetic poles is much more complex that people usually imagine; the Earth can't be modelled as a vast bar magnet. There are two poles - the Geomagnetic pole, which is where compasses point, and the Dip pole, which is where the magnetic dip (the angle of the lines of force to the surface) is vertical. The North Geomagnetic pole (the once responsible for variation) is actually not moving very much; it's in the Canadian Arctic Archipelago. The Dip Pole is scooting off over the Arctic ocean at a rate of knots, and is actually nearer Russia than Canada.
The situation in the south is similar, but the poles are not antipodal, so it isn't a mirror image of what's happening in the North.
BelleSerene
Well-Known Member
That answers Dolabriform's question in post #20 then.
dolabriform
Well-Known Member
I can't wait to see the amendments to all the RYA training on how to correct charts once this has happened
BelleSerene
Well-Known Member
I can't wait to see the amendments to all the RYA training on how to correct charts once this has happened
Copy them on to transparent paper and flip them vertically?
johnalison
Well-Known Member
There is also the question of nomenclature. Is our current North Pole to be renamed 'South', so that all the world's magnets can keep their labels, or is it to stay as 'North', in which case all the magnets will be wrong? Who decides this? Is it the IMO or a bunch of geophysicists somewhere?
AntarcticPilot
Well-Known Member
It's worse than that - the North Magnetic Pole is actually a south pole - think about it, opposite magnetic poles attract, same poles repel. So, to attract the north pole of a magnet, the Earth's North magnetic Pole must be a south pole!
The nomenclature won't change - the terms "north and south" in magnetism are akin to positive and negative in other contexts.
RichardS
N/A
But perhaps the North pointing end of a compass is actually a magnetic South pole and we only call it North because that's the way it points.
Richard
Lon nan Gruagach
Well-Known Member
But perhaps the North pointing end of a compass is actually a magnetic South pole and we only call it North because that's the way it points.
Richard
It is an error to assign an isolated polarity to the ends of a magnet. The full term is "North seeking" or South seeking", ok pedants the full terms are yadda yadda yadda.
So it does not matter whether a particular end of a magnet is +magnetism or -magnetism, these have not been defined. Lets face it, science will always have egg on its face over the electron débâcle.
What y'all are going to have to decide is after the flip, well more of a slop or a splurge than a flip, is whether you change the labels on the magnets or change the labels on the maps.
edit add:
Mebby we should re-label magnets anyway, instead of N and S we should draw polar bears or penguins
lpdsn
Well-Known Member
That's interesting. I have to admit I'm struggling to visualise the field lines where the geomagnetic pole and dip pole are separated by a significant distance. If you were between them where would a compass point?
I presume it is the geomagnetic pole which would also determine the direction of magnetism of stripes either side of a mid-ocean ridge. So if that isn't moving much do we other evidence that points to a likely flip in the near (relatively speaking) future? After all, the dip pole could've gone for a quick spin round the Arctic in the past but if it hasn't left any evidence how do we know whether it is normal or the start of a flip.
PS maybe a magnetic pole gybe is a better term that a flip. Especially if it involves a dip pole.
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Lon nan Gruagach
Well-Known Member
That's interesting. I have to admit I'm struggling to visualise the field lines where the geomagnetic pole and dip pole are separated by a significant distance. If you were between them where would a compass point?
I presume it is the geomagnetic pole which would also determine the direction of magnetism of stripes either side of a mid-ocean ridge. So if that isn't moving much do we other evidence that points to a likely flip in the near (relatively speaking) future? After all, the dip pole could've gone for a quick spin round the Arctic in the past but if it hasn't left any evidence how do we know whether it is normal or the start of a flip.
PS maybe a magnetic pole gybe is a better term that a flip. Especially if it involves a dip pole.
This: https://www.scientificamerican.com/article/the-earth-has-more-than-one-north-pole/ explains it...
The magnetic north pole is the one you will use, its the dip pole and where compass needles end up (or down I guess). The other, the geomagnetic north pole is where the dip pole would be IF the the Earth's magnetic field were generated by a single bar magnet wit all the squiggly bits evened out.
BelleSerene
Well-Known Member
I guess there are a few options.
1. Once the poles flip, we call them Modern North (to be shown downwards on the maps) and Modern South (to be shown upwards).
- In another three quarters of a million years, our nano-engineered successors are to call them Postmodern North (to be shown upwards) and Postmodern South.
- Compasses can remain unchanged and will still work. Maps will still look the same. Yachting magazines sell compass-rose stickers with North at the bottom, to paste over the ones printed on old-polarity charts. ISO 92476 is established to accredit the correct placement of such stickers.
- Government takes the credit, declaring that the change it just made by United Nations Treaty to the magnetic polarity of the planet was necessary to keep pace with societal advancement.
- The French claim to have invented the system along with the rest of post-modern 'philosophy', and so fight to have their shorter terms Nord and Sud mandated instead.
- In another three quarters of a million years, our nano-engineered successors are to call them Classical North (to be shown upwards) and Classical South.
- Compasses can remain unchanged and will still work. Yachting magazines have to give away little stickers that say 'New' along with their stick-on New Compass Roses.
- Government takes the credit, declaring through a United Nations treaty that whilst the experts may not yet agree whether the change in the earth's polarity was due to fracking, excessive working hours, jihad or man's sin, if we don't all invent new taxes to fund research to find out which it was, these changes could be happening every year by the end of our lifetimes and at gigahertz frequency by the time our children die, leading to the death of our grandchildren from the resulting radiation.
- The French, indignant at their new position in the inferior hemisphere, turn up their noses every time they pronounce the Nouveau bit, just as they used to when referring to Nouveau-Monde wines or the Nouveaux Riches.
- In another three quarters of a million years, our nano-engineered successors are to maintain North (shown upwards) and South (shown downwards), but the maps get flipped again.
- The magnetic compass industry gets a boost, the mapping industry gets a huge one, and we all get a headache. Yachting forums create threads such as this one on whether we really need compasses now that GPS and its successors are so well established.
- Government takes the credit, pronouncing through a United Nations Declaration that the relegation of certain nations to the bottom of the page was necessary to right the wrongs of centuries of Northern Privilege. Social Justice Warriors triumph at the 'gutterisation' of those nations and the 'RightHeighting' of other ones.
- The French, who always knew in their hearts that England was near their bottom not their head, seize on the cartography industry's once-in-a-millenium opportunity to reprint the world's maps by bidding for a second time to move 0º longitude to Paris while we're at it.
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RichardS
N/A
Although I'm not sure why you're quoting me rather than AntarcticPilot .... I was the one who ended my post with a smiley.
Richard