May 12

Traveling to the North Pole, Part 5: Ice and Magnetism

Category: Arctic,Travel

Today we worked close to the magnetic north pole.

I should explain that there are two north poles; the “true” (or “geodetic”) one that is found at the “top” of the world where lines of longitude meet, and the magnetic one, which is the attractor for all “north” magnet ends on the earth.  The geodetic pole is fixed; it never moves and can be thought of as sitting on the floor of the Arctic ocean, covered by ocean and surrounded by a surface icecap.  The magnetic one wanders; in my lifetime it has moved hundreds of miles.  The magnetic north pole is currently south-west of the geodetic  north pole, off the coast of arctic Canada, and is moving towards Russia.

There was a lot of beautiful ice there covered with hoarfrost, and occasional startling blue patches that must be seen to believed.  We met our science goals and left, having visited the region for only a couple of hours.  We were not right on top of the pole, but close enough that my compasses didn’t agree, and didn’t always return to the same place; they seemed confused.  It is this way for miles in every direction.  I tried using my map navigation compass, my wrist compass, and my iphone; none of them agreed in the slightest.  A compass that was spun or shaken would not go back to a fixed point, but would wander around, occasionally finding renewed vigor in pointing to a random spot for a while. As you can see from the image, a compass turned does not re-orient to magnetic north.  I took the pictures from the same orientation.  

Click on any image to enlarge.





3 Comments so far

  1. Gaelyn May 12th, 2012 11:27 PM

    What a crazy world. Two north poles. Seems like the “true” human chosen pole should be false and the magnetic be true.

    Those ice crystals are like delicate lace.

  2. Dan Greenspan May 13th, 2012 9:22 AM

    Although the north magnetic pole is the location to which all compasses point north, geographic (also called “geodetic”) north and south mark the axis of the earth’s rotation. So both are “true” in the sense that they are based upon aspects of the physical world and are not merely human inventions. But I agree that it seems silly to pick one and arbitrarily call it “true.” There is one reason, though, to prefer geodetic north to magnetic north for purposes of navigation: it doesn’t move. Magnetic north is moving all over the place. In our lifetimes it has moved dozens or hundreds of miles, and is currently headed northwest towards siberia. Periodically it switches places with the south magnetic pole! “True,” geodetic north at least has the decency to stand still for us.

  3. DiAnne May 19th, 2012 11:45 AM

    Ruby and I love the snowflake!!! Super cool!!!

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