Mission: Swarm

The Earth’s magnetic field is an essential part of the planet. It protects us from the harsh conditions of the universe and allows life as we know it to thrive. And it’s been changing drastically, weakening over some parts and strengthening over others.

In a quest to understand more, two years ago, the European Space Agency (ESA) created Swarm—a mission solely dedicated to observing and understanding the Earth’s magnetic field, and any changes happening to it.

Observations now prove that the Earth’s magnetic field is weakening 10 times faster than we thought. One of the reasons proposed is that, perhaps, our magnetic field is “flipping,” a normal phenomenon believed to occur every 100,000 years or so.

Watch: The Clearest Map So Far of Our Magnetic Field

The red regions highlight where the field got stronger, and the blue regions show a weakening. Credit: ESA

And after years of gathering data, Swarm’s three satellites were able to map the changes in strength to the Earth’s magnetic field in detail.

"Swarm data are now enabling us to map detailed changes in Earth's magnetic field, not just at Earth's surface but also down at the edge of its source region in the core," says Chris Finlay of DTU Space in Denmark, who leads the ESA project.

"Unexpectedly, we are finding rapid localised field changes that seem to be a result of accelerations of liquid metal flowing within the core."

The map from Swarm is the clearest picture we have so far of how the magnetic field has changed. According to ESA: “It shows clearly that the field has weakened by about 3.5% at high latitudes over North America, while it has strengthened about 2% over Asia. The region where the field is at its weakest – the South Atlantic Anomaly – has moved steadily westward and weakened further by about 2%.”

Oh, and the magnetic North pole is moving East towards Asia, too.

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