North Pole isn’t where it’s supposed to be
SARAH KAPLAN Magnetic north is not where it used to be.
Since 2015, the place to which a compass points has been sprinting toward Siberia at a pace of more than 50 kilometres a year. This week, after a delay caused by the month-long partial government shutdown in the United States, humans have finally caught up.
Scientists on Monday released an emergency update to the World Magnetic Model, which cellphone GPS systems and military navigators use to orient themselves. It’s a minor change for most of us — noticeable only to people who are attempting to navigate very precisely very close to the Arctic.
But the north magnetic pole’s inexorable drift suggests that something strange — and potentially powerful — is taking place deep within Earth. Only by tracking it, said University of Leeds geophysicist Phil Livermore, can scientists hope to understand what’s going on.
The planet’s magnetic field is generated about 3,200 kilometres beneath our feet, in the swirling, spinning ball of mol- ten metal that forms Earth’s core. Changes in that underground flow can alter the Earth’s magnetic field lines — and the poles where they converge. Consequently, magnetic north doesn’t align with geographic north (the end point of Earth’s rotational axis), and it’s constantly on the move. Records of ancient magnetic fields from extremely old rocks show that the poles can even flip — an event that has occurred an average of three times every million years.
The first expedition to find magnetic north, in 1831, pinpointed it in the Canadian Arctic. By the time the U.S. army went looking for the pole in the late 1940s, it had shifted 400 kilometres to the northwest. Since 1990, it has moved a whopping 965 kilometres, and it can be found in the middle of the Arctic Ocean, 4 degrees south of geographic north — for the moment.
Curiously, the south magnetic pole hasn’t mirrored the peregrinations of its northern counterpart. Since 1990, its location has remained relatively stable, off the coast of eastern Antarctica.