The north magnetic pole just changed

 The north magnetic pole just changed

 

 

 

 

 

 

 

Magnetic north just changed. Here's what that means.The foundation of many navigation systems, the World Magnetic Model finally got a much-needed update with the end of the U.S. government shutdown.

  

Magnetic north has never sat still. In the last hundred years or so, the direction in which our compasses steadfastly point has lumbered ever northward, driven by Earth's churning liquid outer core some 1,800 miles beneath the surface. Yet in recent years, scientists noticed something unusual: Magnetic north's routine plod has shifted into high gear, sending it galloping across the Northern Hemisphere-and no one can entirely explain why.

The changes have been so large that scientists began working on an emergency update for the World

Magnetic Model, the mathematical system that lays the foundations for navigation, from cell phones and ships to commercial airlines. But then the U.S. government shut down, placing the model's official release on hold, as Nature News First Reported earlier this year.

  Now, the wait for a new north is over. The World Magnetic Model update was officially released on Monday, and magnetic north can again be precisely located for people around the world.

Questions still likely abound: Why is magnetic north changing so fats? What were the impacts of the updates delay? Was there really a geologic reason Google maps sent me off course? We've got you covered. 

What is magnetic north?

 Magnetic north is one of three "north poles" on our globe. First, there's true north, which is the northern end of the axis on which our planet turns.

But our planet's protective magnetic bubble, or magnetosphere, is not perfectly aligned with this spin. Instead, the dynamo of Earth's core creates a magnetic field that is slightly titled from the planet's rotational axis. The northern end of this planet-size bar magnet is what's known as geomagnetic north-a point sitting off the northwest coast of Greenland that's changed position little over the last century. 

Then there's magnetic north, what your compass locates, which is defined as the point at which magnetic field lines point vertically down. Unlike geomagnetic north, this position is more susceptible to the surges and flows in the swirl of liquid iron in the core. These currents tug om the magnetic field, sending magnetic north hooping across the globe.

What is the World Magnetic Model?

James Clark Ross first located magnetic north in 1831 in the scattered islands of Canada's Nunavut territory. Since then, the pole has largely marched north, traversing hundreds of miles over the last several decades.

To keep up with all these changes, the U.S. National Oceanic and Atmospheric Administration and the British Geological Survey developed what eventually became known as the World Magnetic Model, "so they would all be on the same map, essentially." 

The model is updated every five years, with the last update in 2015. Between each update, scientists check the model's accuracy against data from ground magnetic observatories and the European Space Agency's Swarm mission-a trio of magnetic field mapping satellites that zip around Earth 15 to 16 times each day. Until now, this seemed sufficient to keep up with magnetic north's march toward Siberia.

In the mid 1900s, the north magnetic pole was lumbering along at less than a hundred feet each day. adding up to less than seven miles of difference each year. But in the 90s, this started to change. By the early aughts, magnetic north was chugging along at some 34 miles each year.

By early 2018, scientists realized that the model would soon exceed the acceptable limits for magnetic-based navigation. Something had to be done before the model's next regular update, slated for 2020.