Known as the South Atlantic Anomaly, this region is now showing signs of structural changes, shifting eastward and developing new areas of instability.
Researchers using satellite data from the European Space Agency have tracked this anomaly since 2014. The field weakening threatens satellites and spacecraft by increasing their exposure to solar radiation and charged particles—conditions that can disrupt onboard systems or shorten mission lifespans.
The magnetic field acts like a protective bubble, shielding Earth and objects in low orbit from harmful space radiation. In the South Atlantic Anomaly, that bubble thins dramatically, reducing protection at lower altitudes than usual. This not only affects space-based equipment but also provides critical insight into the dynamic processes occurring deep beneath Earth’s surface.
Anomaly Growing and Drifting Toward Africa
Since its detection, the South Atlantic Anomaly has continued to widen and now spans an area approaching half the size of continental Europe. According to Live Science, satellite observations show that the anomaly is no longer a single block—it has shifted and extended, forming a second, weaker lobe toward southern Africa. This new area appears to be deteriorating faster than the core of the anomaly near South America.
“This isn’t just a static feature,” said, in a statement, Chris Finlay, lead author of the study and professor at the Technical University of Denmark. “It’s changing differently towards Africa than it is near South America.” This irregular development suggests local factors may be accelerating the decline in specific zones.
The Swarm satellite constellation, which has been monitoring Earth’s magnetic field since 2013, continues to provide the high-resolution data driving these discoveries. Without it, the scale and direction of this anomaly would likely remain unnoticed.
Flux Disturbances Beneath the Mantle
At the root of the South Atlantic Anomaly lie strange magnetic behaviors known as reverse flux patches. These are regions where magnetic field lines behave unexpectedly—diving back into Earth’s core instead of radiating outward. This inversion is unusual and believed to stem from turbulent flow patterns in Earth’s molten outer core, which generates the global magnetic field.
These anomalies are concentrated where the outer core meets the mantle, creating local zones of weakening that contribute to the anomaly’s spread. According to indy100, one of these flux patches is currently drifting westward over Africa, pulling the anomaly along with it.
Normally, field lines in the southern hemisphere emerge from the core and arc outward. But in the anomaly zone, this flow is disrupted, weakening the magnetic field in a non-uniform way and complicating efforts to model its behavior.
A Tale of Two Hemispheres
The anomaly’s evolution isn’t isolated. Changes are also occurring in the northern hemisphere, with contrasting trends. Data from the Swarm mission show that the magnetic field above Canada has diminished slightly in strength, while the field over Siberia has intensified.
The strong-field region over Canada has contracted by an area the size of India, whereas Siberia’s magnetic influence has grown by an area comparable to Greenland. These shifts are associated with the gradual migration of the northern magnetic pole toward Siberia—a movement tracked for decades but still not fully understood.
These transformations further confirm that Earth’s magnetic field is neither static nor symmetrical. Instead, it’s in constant motion, shaped by hidden, high-energy flows more than 3,000 kilometers beneath the surface. Anja Strømme, ESA’s Swarm mission manager, emphasized the value of continued monitoring, saying the satellite data provide a rare “big picture” view of these long-term planetary changes.
Continued Surveillance, Rising Stakes
The South Atlantic Anomaly remains under close watch as researchers assess its impact and behavior. The Swarm satellites remain in good condition and are expected to continue collecting data beyond 2030, offering one of the longest-running, high-resolution views of Earth’s magnetic environment.
Though the anomaly doesn’t pose a direct threat to people on the ground, its influence on space hardware and orbital operations is becoming more pronounced. Increased exposure to high-energy radiation in this zone can damage electronics, corrupt onboard data, and even cause temporary satellite blackouts.