Scientists struggle to model the movement of the magnetic north pole. In our live, online ASA 105 coastal navigation course, a real instructor teaches you about this, and why you can basically ignore it.
We’re having a lot of fun with our “Live 105” classes on Zoom! Real instructor, real time, real students – in the same, small manageable class sizes we have for in-person courses. One of our current students sent a link to a BBC article related to the content of a 105 course, which is of course all about…
COASTAL NAVIGATION.
The link Cristina sent? A BBC piece about the movement, or wandering, of the magnetic north pole. We link to the piece at the end of this Rant. For now…
In that pic: the thin aqua line traces the approximate motion of the magnetic north pole from 1840 to 2019. It’s accelerated recently, creating a scientific buzz. (Pic is a still frame from a video in the BBC piece we link to below.)
THE IDEA: the magnetism of earth is both consistent and inconsistent. Compasses point to the same place on earth with minor wiggles. This is close to the geographic north pole, or the rotational axis of earth. If Atlas stopped shrugging, and spun earth on the tip of his finger like a Harlem Globetrotter, it would be on the South Pole, with the North Pole exactly at the other end – or “top.” But, “top” is arbitrary, ain’t it? Space has no direction. We’re floating in space. And, what’s more…
It might flip! Yup. Magnetic North and South have reversed from time to time. Maybe every few hundred thousand years. The question is whether this could happen within our lifetimes. And, partially due to accelerated movement of the Mag North Pole, scientists suspect it might.
1, 2, 3… SWITCH! Oops…
THE ARTICLE’S PATH: Scientists studying this have noted the acceleration of the drift of the Mag North Pole recently, and have updated the global model used for that as it relates to GPS, which is critical to precise navigation. That’s not always super critical itself; as we teach in Start Navigating ( ASA 105), it’s almost more important to check progress in real time than plan the path perfectly to begin with. Basically, they think they’ve identified two molten “hot spots” in the earth’s outer core that are having a tug of war over the magnetic north pole. Kewl! Or, very hot…
That gets into some chart nitty-gritty: the compass rose. It’s a tool to measure direction, and it looks pretty kewl too. Check it…
In that pic: a section of the 12363 chart of Western Long Island Sound, with City Island (“City I”) on the right, which is home to the Sailing Center. It’s about half the length of Manhattan away from it; northern MannyHanny is on the bottom left of the chart. It has a nice, large compass rose, or rings that measure direction. The outer ring is for true, or geographic, north – with a star at the top for Polaris, the actual North Star. The inner ring is for magnetic north, which is where compasses point more or less. In navigation classes, we teach how to use these to plot out a course to steer a boat.
THE CONVENTIONAL WISDOM: look at the annual increase/decrease in the variation as listed in rose (the pic below blows it up for you). It’s usually a few “minutes” a year. Each minute = ..? It’s a measly 1/60th of 1 degree of the compass. Yup; slicing hairs with razor blades. Anywho… if your chart is out of date, the idea is to multiply the number of years of ‘stale’ by the number of minutes of change, and add or subtract accordingly. And, get the +/- right!
NYSC knows better… our Director and HBIC (Head Bozo in Charge), Captain Card, had a suspicion about something years ago. He compared every training chart the government produced, which are all frozen in time going back a far as the early 1980’s, to the updated, real-life versions of those charts. The conclusion? It’s silly to try to project any annual increase or decrease into the future. We expand on that and reveal the goods in class, and in our own in-house text book that we supply to students (and sell on the side). Despite what other books say, just skip this step. Much smarter move: get a current chart, for all the more obvious reasons.
Maybe we’ll be lucky (?) enough to see the poles flip in our lifetimes! Will planes drop from the sky, and cars run off the roads? Well, if they can’t figure that their GPS and compasses are basically pointing backward, we can’t help them.
Your takeaway? Use updated charts to plot courses to your destinations, and casually follow along with the progress of Mag North Pole’s wanderings across cold areas most of us will never visit.
And now, as promised, the link to the BBC piece…
https://www.bbc.com/news/science-environment-52550973
Happy hunting!