A giant weak spot in Earth’s magnetic field is now half the size of Europe
Science Daily
February 25, 2026
AI-Generated Deep Dive Summary
A significant weak spot in Earth’s magnetic field, known as the South Atlantic Anomaly, has grown dramatically over the past decade. New data from ESA’s Swarm satellite constellation reveals that this anomaly expanded by nearly half the size of Europe between 2014 and 2025. This weakening of the magnetic field is particularly concerning because it exposes satellites to higher levels of radiation, increasing the risk of technical malfunctions and hardware damage. The anomaly’s rapid expansion highlights unusual activity deep within Earth’s molten outer core, where the planet’s magnetic field is generated.
Earth’s magnetic field is created by the movement of molten iron in its outer core, which generates electric currents that produce the electromagnetic field protecting the planet from harmful cosmic radiation. The South Atlantic Anomaly was first identified in the 19th century and has been closely monitored due to its implications for space safety. While it originally stretched southeast of South America, recent findings show that an area southwest of Africa has weakened even faster since 2020, suggesting complex dynamics at play.
Scientists attribute this unusual behavior to reverse flux patches—areas where the magnetic field behaves unexpectedly—at the boundary between Earth’s liquid outer core and solid mantle. These patches cause parts of the field to dip back into the core instead of rising outward, contributing to the weakening observed in specific regions. This phenomenon is particularly evident near Africa, where one such patch has been moving westward, intensifying the anomaly’s effects.
The Swarm mission, consisting of three satellites that measure Earth’s magnetic signals, has set a new record for continuous space-based monitoring of the magnetic field. Launched in 2013, the mission provides critical data for understanding Earth’s interior and tracking space weather hazards. The latest findings from Swarm highlight the importance of long-term magnetic field observations for navigation systems, satellite operations, and studying Earth’s dynamic processes.
This research not only sheds light on the intricate workings of Earth’s magnetic field but also underscores the need for continued monitoring to understand how these changes might affect life on Earth. From protecting satellites to unraveling the mysteries of our planet’s core, the South Atlantic Anomaly serves as a reminder of the delicate balance maintained by Earth’s magnetic shield and the importance of studying its fluctuations.
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Originally published on Science Daily on 2/25/2026