The planet's magnetic field is in danger again, and geologists are quite baffled.
Earth's magnetic poles can travel a few kilometers each year, but the movement of the North Pole has become increasingly unknown in recent years. For currently unclear reasons, the magnetic North Pole seems to slip from Canada to Siberia at an irregular speed, as reported in Nature .
"The North's Position The magnetic pole seems to be dominated by two large magnetic fields, one under Canada and one below Siberia," said Phil Livermore, a geomagnetist at the University of Leeds in the United Kingdom, at the last American Geophysical meeting Union, [1
"The Siberian Patch wins the competition."
Every five years, the National Oceanic and Atmospheric Administration (NOAA) maps the Earth's magnetic field into the World Magnetic Model (WMM). This was last published in 2015, the next edition is scheduled for 2020, but this crazy behavior forced the scientists to revise the map earlier than expected. Unfortunately, the revised WMM was due to be released on January 15, but was postponed to January 30 due to the ongoing government shutdown.
Earth's magnetic field is generated by molten iron in its core, which swirls around by convective currents. It is a rather chaotic situation there, resulting in a complex pattern of magnetism that is extremely difficult to model and predict. To make things even more complicated, South America's unusually violent geomagnetic impetus appeared in 2016, which is believed to have contributed to the unforeseen changes.
However, it remains largely unclear why the magnetic field under Canada appears to weaken in such a strange way.
You may wonder if that matters. The magnetic field is central to many forms of navigation. The most obvious is that a compass is based on magnetic fields, but more modern navigation systems also use the field as a bearing. These anomalies should not be strong enough to screw it up, but it's certainly something that geologists need to keep an eye on.
In fact, tremendous changes in the magnetic field can take place. The scientists know that Earth can go through a phenomenon known as "geomagnetic inversion," in which these magnetic poles literally switch sides. The last time this happened was 781,000 years ago, but it is believed to have occurred every 20,000 to 30,000 years over the last 20 million years (though there were exceptions).