Poles Shifting

[hackandhue]

I was reading a lot of the poles shifting, and the ramifications of this. (tampa had to change the headings on its runway). I assume that this means some sailing charts are going to need to be updated? Just curious what you guys thing. "True North" and "Magnetic North" should have changed, correct?

Magnetic Poles Shifting | Seagull Striker's Going Sailing

[SlowButSteady]

The earth's magnetic axis is ALWAYS moving around a bit. Note that the compass rose on a chart always gives the annual increase or decrease.

[jackdale]

Originally Posted by SlowButSteady

The earth's magnetic axis is ALWAYS moving around a bit. Note that the compass rose on a chart always gives the annual increase or decrease.

More than just a bit.

The Canadian government has made several measurements since, which show that the North Magnetic Pole is moving continually northwestward. In 1996 an expedition certified its location by magnetometer and theodolite at 78°35.7′N 104°11.9′W.[8] Its estimated 2005 position was 82.7°N 114.4°W, to the west of Ellesmere Island in Canada.[9] During the 20th century it moved 1100 km, and since 1970 its rate of motion has accelerated from 9 km/year to aproximately 41 km/year, or 1.3 mm/sec (2001–2003 average; see also Polar drift). If it maintained its present speed and direction it would reach Siberia in about 50 years, but it is expected to veer from its present course and slow its rate of motion.

Canada has been very magnanimous in letting other countries use the magnetic pole. Russia may not be so willing.

[QuickMick]

Well, the stars wont shift.
as to SlowButSteady, good article here:
NASA - Earth's Inconstant Magnetic Field

as to cataclysmic pole shift... heck i didnt think nostradamus was right and i dont believe in the the aztec/mayan doomsday calender either.

[SlowButSteady]

When I said "a bit", I was referring to the annual change. I'm well aware that the earth's mag field moves, and even "flips" from time to time. Those magnetic "stripes" in the link QM posted were part of the early proof of plate tectonics (and happen to be the subject of a lecture in the Intro to Oceanography course I teach from time to time). You might also note that the movement of the magnetic axis also changes the compass "dip" (or magnetic inclination/declination) at any particular point on the earth's surface. This three-dimensionality of the magnetic field has all sorts of biological and paleontological consequences, in addition to screwing up the compasses of vessels that travel between the northern and southern hemispheres.

[hackandhue]

so unless we get a pole flip, which *could* happen next year according to NASA, than what is really significant enough to matter? I imagine now with GPS it matters less because you can just update your software, or it will do so automatically.

[jackdale]

We still teach how get a fix using a handbearing compass. Variation matters.

We also teach deviation, but for some crews that is a part of their nature.

[centaursailor]

Originally Posted by QuickMick

Well, the stars wont shift.
as to SlowButSteady, good article here:
NASA - Earth's Inconstant Magnetic Field

as to cataclysmic pole shift... heck i didnt think nostradamus was right and i dont believe in the the aztec/mayan doomsday calender either.

The stars don,t shift, well not very much anyway. The earth spins tho so the stars appear to revolve aroung the North star as the night hours tick by. Just dont follow any one other than the pole star for long periods or you will be off course.
Happy sailing

[QuickMick]

isnt that what i said?

[centaursailor]

Originally Posted by QuickMick

isnt that what i said?

Fair enough.