Just when you though it was safe to venture out, the National Oceanic and Atmospheric Administration released an unexpected update. Magnetic North is on the move — faster than expected. That’s right, we know magnetic north moves around, but now it’s happened at a surprising rate. Instead of waiting for the normal five year interval before an update on its position, NOAA have given us a fresh one a bit earlier.
There are some things that we can safely consider immutable, reliable, they’ll always be the same. You might think that direction would be one of them. North, south, east, and west, the points of the compass. But while the True North of the Earth’s rotation has remained unchanged, the same can not be said of our customary method of measuring direction.
Earth’s magnetic field is generated by a 2,000 km thick outer core of liquid iron and nickel that surrounds the planet’s solid inner core. The axis of the earth’s internal magnet shifts around the rotational axis at the whim of the currents within that liquid interior, and with it changes the readings returned by magnetic compasses worldwide.
The question that emerged at Hackaday as we digested news of the early update was this: as navigation moves inexorably towards the use of GPS and other systems that do not depend upon the Earth’s magnetic field, where is this still relevant beyond the realm of science?
Finding Your Way with Map and Compass
Every former Scout will have learned how to take a compass bearing and relate it to a map. But do you remember learning the difference between the compass needle and the grid on that map?
Generally map publishers use two standards, True North is used for the map grid — it’s where longitudinal lines meet at the northern tip of the planet. Magnetic north is where your compass actually points and has to do with that pesky moving target. Publishers will note the local offset between Magnetic North and the North of the map grid. Anyone trying to earn their Map Reader badge will add or subtract from their compass reading as required. In more serious fields where precise navigation is critical, every ship and aircraft will have a magnetic compass as an aid to its navigator.
Where Does the Compass Rest in Our Modern World?
It’s true then, that a magnetic compass is a useful instrument, and given one along with a good map or chart everyone from a pimply teen in the wilderness to a veteran sea-dog on the bridge can use it to make their way across the land or the ocean. But the modern Scout has a smartphone with GPS in their pocket and both pilots and captains have had reliable (in level flight at least!) gyrocompasses for decades before they ever saw a GPS. Is there still a place for a magnetic compass, or will it eventually go the way of the astrolabe or the Decca Navigator?
The most obvious place we still see a magnetic compass is automobiles. They’re digital now, but still rely on the earth’s magnetic north pole. Your smartphone has one of these sensors as well and it’s used in conjunction with inertial sensors and GPS readings when using your phone for navigation. But we’re really looking for more places where our lives are affected by magnetic north, so do tell in the comments below!
In the event that everything in our high-tech house of cards has failed, and all that is left is the magnetic compass, this instrument could prove life-saving. With this convenient excuse of a magnetic north heading update, now is a great time to discuss all the ways this simple phenomenon has had profound impacts on our lives and the development society.