Will Santa get home safe? New World Magnetic Model reveals movements in the Earth’s magnetic field18/12/2019 By BGS Press
If you’ve ever wondered how Santa visits millions of homes across the globe in just one night, it’s because he has a little help from science. And the good news is, he won’t get lost on his travels this year – provided that he follows his compass home.
Santa has reason to be cautious when using his compass, because scientists have found the magnetic north pole is moving across the Arctic region at its fastest rate in 400 years, according to the latest satellite data.
Magnetic north is the point on the Earth’s surface at which the magnetic field lines point vertically downwards.
Unlike ‘true north’ which is the geographic axis on which our planet turns, magnetic north is where your compass points to. The magnetic field is generated by the flow of liquid iron in the Earth’s core, which creates electric currents, similar to how a bicycle dynamo works.
As the movement of the north magnetic pole is rapid and unpredictable, scientists at the British Geological Survey team up with the U.S. National Oceanic and Atmospheric Administration every five years to update the World Magnetic Model (WMM), a series of magnetic field maps which help underpin navigation systems.
The latest model shows magnetic north racing across the Northern Hemisphere at around 50 km per year, as it moves from the Canadian Arctic towards Siberia.
“It’s the fastest recorded shift seen since the mid 16th-century,” said Ciaran Beggan, a geophysicist at the British Geological Survey.
“Magnetic records show the magnetic North Pole has been meandering about Canada from 1590 until 1990 when it suddenly accelerated gain speed over the past 30 years, going from less than 10 km (6.2 miles) per year to almost 60 km (37 miles) per year.
“However, on the other side of the planet, the South Magnetic Pole has moved very slowly, drifting around the coast of Antarctica in the same period.”
Magnetic north has never stood still, and in the last 100 years or so, the direction in which our compasses point has marched steadily north, traversing hundreds of miles over the last few decades.
Scientists are yet to understand what has caused an unprecedented gear shift over the last 20 years, but Dr Beggan says: “We know there are irregular changes in the planet’s liquid outer core and that the magnetic field is also weakening under Canada, but it’s not yet possible to say exactly for sure why magnetic north is changing so fast.
“The good news is that at Christmas this year, the magnetic pole makes its closest approach to the geographical Pole, so if Santa uses his compass he’ll be pretty much home safe!”
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The World Magnetic Model
The World Magnetic Model (WMM) is a standard model of the core and large-scale crustal magnetic field.
The WMM is essential in electronic devices that rely on precise information, from satellite communication to aviation, shipping and even our smartphones.
Due to changes in the Earth’s core field, the WMM is updated every five years. Scientists check the model’s accuracy against data from 160 ground-based magnetic observatories and magnetic-field mapping satellites that orbit around the Earth up to 15 times a day, part of the European Space Agency’s Swarm mission.
The measurements are used to construct a complex representation of the many different sources of Earth’s magnetic field and its time variation.
For more information please see: https://geomag.bgs.ac.uk/research/modelling/WorldMagneticModel.html
British Geological Survey
The British Geological Survey (BGS) is a world leading applied geoscience research centre that is part of UK Research and Innovation (UKRI) and affiliated to the Natural Environment Research Council (NERC). BGS core science provides objective and authoritative geoscientific data, information and knowledge to inform UK Government on the opportunities and challenges of the subsurface. It undertakes national and public good research to understand earth and environmental processes in the UK and globally. The BGS annual budget of approximately £60 million pa is funded directly by UKRI, as well as research grants, government commissions and private sector contracts. Its 650 staff work across the UK with two main sites, the head office in Nottingham and Lyell Centre in Edinburgh. BGS works with more than 150 private sector organisations, has close links to 40 universities and sponsors about 100 PhD students each year. Please see www.bgs.ac.uk.