Since it was first measured in 1831, we have known that the magnetic north is constantly on the move. However, its tendency to slowly roam has stepped up a pace recently - so much so that the World Magnetic Model has had to be updated urgently with the pole’s new location, vital for navigation on smartphones, for example. ESA’s magnetic field Swarm mission has been key for this update.
The World Magnetic Model, the basis for many navigation systems used by ships, Google maps and smartphones, relies on the accurate knowledge of Earth’s magnetic field. Since magnetic north never stands still, the model has to be revised periodically - but a surge in pace has meant that an update was needed ahead of schedule.
Driven largely by the churning of fluid in Earth’s core, which generates the magnetic field, the magnetic north pole has always drifted, and geological evidence shows that every few hundred thousand years or so it even flips, so that north becomes south.
Around 50 years ago, the pole was ambling along at around 15 km a year, but now it is sprinting ahead at around 55 km a year. In 2017, it crossed the international date line, leaving the Canadian Arctic and heading towards Siberia.
The World Magnetic Model is used to keep track of changes in the magnetic field and updated every five years by the US National Oceanic and Atmospheric Administration and the British Geological Survey.