Earth’s Magnetic Field Weak Spot Expands Dangerously

Earth’s Magnetic Field. Credit: NASA Goddard Space Flight Center / Flickr / CC BY 2.0

A anemic portion successful Earth’s magnetic field, known arsenic the South Atlantic Anomaly, has expanded astatine an alarming complaint implicit the past decade, scientists say. Using 11 years of information from the European Space Agency’s Swarm outer mission, researchers recovered that the anomaly has grown by an country astir fractional the size of continental Europe since 2014.

The South Atlantic Anomaly is simply a portion wherever the planet’s magnetic tract is unusually weak, stretching from South America to confederate Africa. The magnetic field acts arsenic Earth’s invisible shield, deflecting harmful cosmic rays and charged particles from the Sun.

As this shield weakens, much radiation penetrates the atmosphere, raising concerns for satellites and spacecraft operating supra the region.

Uneven weakening raises caller technological concerns

“The South Atlantic Anomaly is not conscionable a azygous block,” said Chris Finlay, pb writer of the caller survey and Professor of Geomagnetism astatine the Technical University of Denmark. “It’s changing otherwise towards Africa than it is adjacent South America. There’s thing peculiar happening successful this portion that is causing the tract to weaken successful a much aggravated way.”

The findings, published this period successful Physics of the Earth and Planetary Interiors, amusement that the anomaly expanded steadily betwixt 2014 and 2025. A conception of the Atlantic Ocean southwest of Africa has seen an adjacent faster driblet successful magnetic spot since 2020. This uneven weakening points to analyzable forces heavy wrong Earth.

Strange magnetic behaviour heavy beneath the surface

Researchers hint these changes to the planet’s liquid outer core—an water of molten robust astir 3,000 kilometers beneath the surface.

The question of this metallic generates electrical currents, which nutrient the magnetic tract that surrounds and protects the planet. However, nether the South Atlantic, scientists person detected antithetic magnetic behaviour known arsenic “reverse flux patches,” wherever tract lines loop backmost into the halfway alternatively of flowing outward.

Warning: The South Atlantic Anomaly has expanded by an country astir fractional the size of continental Europe since 2014.

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Using 11 years of magnetic tract measurements from the European Space Agency’s Swarm outer constellation, scientists person discovered that the anemic portion in… pic.twitter.com/HFJE6jq2Cg

— Brian Roemmele (@BrianRoemmele) October 14, 2025

“Normally we’d expect to spot magnetic tract lines coming retired of the halfway successful the confederate hemisphere,” Finlay explained. “But beneath the South Atlantic Anomaly we spot unexpected areas wherever the magnetic field, alternatively of coming retired of the core, goes backmost into the core. Thanks to the Swarm information we tin spot 1 of these areas moving westward implicit Africa, which contributes to the weakening of the South Atlantic Anomaly successful this region.”

Swarm ngo delivers unprecedented semipermanent data

The Swarm mission, launched successful 2013 nether ESA’s Earth Observation FutureEO program, consists of 3 identical satellites that measurement magnetic signals from Earth’s core, crust, oceans, and atmosphere.

The ngo has present produced the longest continuous grounds of magnetic tract information from space, giving scientists a clearer presumption of however the planet’s magnetic forces evolve.

ESA’s Swarm Mission Manager, Anja Strømme, said the satellites stay successful fantabulous condition. “It’s truly fantastic to spot the large representation of our dynamic Earth acknowledgment to Swarm’s extended timeseries,” she said. “We tin hopefully widen that grounds beyond 2030, erstwhile the star minimum volition let much unprecedented insights into our planet.”

Risks for satellites and abstraction technology

Scientists accidental the South Atlantic Anomaly’s ongoing enlargement highlights however dynamic—and unpredictable—Earth’s magnetic tract tin be. While determination is nary contiguous information to beingness connected the surface, the anomaly poses increasing risks for satellites, navigation systems, and different abstraction technologies that beryllium connected the planet’s magnetic protection.