CITIZENS NEWS

A growing weak spot in Earth's magnetic shield threatens satellites and global technology

By isabelle // 2025-10-14

• A growing weak spot in Earth's magnetic field is forcing scientists to reconsider its stability.
• The South Atlantic Anomaly has expanded dramatically since 2014 and is drifting westward.
• This region poses a serious threat to satellites used for navigation and communication.
• The weakened field allows more radiation to penetrate, which can damage satellite electronics.
• These changes reveal the dynamic and complex nature of Earth's deep interior.

A mysterious and growing weak spot in Earth's magnetic field is forcing scientists to reconsider the stability of the planet's vital protective shield. This region, known as the South Atlantic Anomaly, has expanded dramatically since 2014 according to data from the European Space Agency’s Swarm satellite constellation, posing an increasing threat to the satellites that modern society depends on for navigation, communication, and weather forecasting.

The shifting magnetic shield

The South Atlantic Anomaly is a vast area over the southern Atlantic Ocean and parts of South America where Earth's magnetic field is significantly weaker than elsewhere. This is not a new discovery, but its rapid evolution is alarming. According to research analyzing 11 years of Swarm data, the anomaly has expanded by an area nearly half the size of continental Europe since 2014. It has grown by up to 25 percent while also drifting westward at a rate of about 14 miles each year. This is not a minor fluctuation but a significant change to a key planetary defense system. This protective magnetic field is largely generated thousands of miles beneath the surface by a swirling ocean of molten iron in Earth’s outer core. Acting like a giant dynamo, the motion of this liquid metal creates electrical currents that produce our electromagnetic field. However, this motion is not constant. Turbulent flows of molten iron generate unusual magnetic patterns that are responsible for the weakening field in this specific part of the planet. Lead author Chris Finlay, Professor of Geomagnetism at the Technical University of Denmark, highlighted the complexity of the changes. He stated, "It's changing differently towards Africa than it is near South America. There's something special happening in this region that is causing the field to weaken in a more intense way." This uneven weakening points to complex and poorly understood processes deep within the Earth.

A direct threat to technology

The consequences of this weakening shield are far from theoretical. The South Atlantic Anomaly poses the greatest threat to satellites passing overhead. In this region, the reduced magnetic field strength allows higher levels of radiation from the sun and cosmic rays to penetrate. This exposure can temporarily disable electronics, corrupt data, or even cause permanent damage to critical hardware. NASA has likened the area to a "pothole in space" that spacecraft must navigate carefully. The satellites most at risk are those providing essential services. This includes the fleets of spacecraft that deliver GPS signals, enable global communications, and monitor weather patterns for the United States and nations around the world. Every time one of these satellites passes through the anomaly, its systems are vulnerable to random hits from high-energy particles. To mitigate this risk, satellite operators are often forced to routinely shut down non-essential spacecraft systems before the craft enters the anomaly zone. The implications extend beyond simple glitches. Significant data loss or the permanent failure of a key satellite component could disrupt countless services that the public and governments rely on daily. From the navigation systems in cars and phones to the data that guides commercial aviation and predicts severe storms, the integrity of this technological infrastructure is directly linked to the health of Earth's magnetic field.

Looking beyond the anomaly

The changes are not confined to the South Atlantic. The same study revealed other significant shifts in the global magnetic field. In northern Canada, the area of a strong magnetic field has weakened, shrinking by an amount comparable to the size of India. Meanwhile, the magnetic field over Siberia has strengthened. These shifts are associated with the movement of the north magnetic pole toward Siberia in recent years, which itself affects global navigation systems. Scientists emphasized that the changes in Earth’s magnetic field highlight its dynamic nature. The Swarm satellites, which have been collecting continuous magnetic field data since 2013, are providing unprecedented insight into the complex forces at work deep inside our planet. For the average person on the ground, the growing anomaly does not pose a direct health risk. Life on the surface remains protected by the atmosphere. However, for satellites, astronauts on the International Space Station, and even high-altitude air travel, the implications are real and require careful attention. This situation demonstrates how changes deep below the planet's surface can ripple outward, affecting technology in space and the daily lives of people everywhere. Sources for this article include: DailyMail.co.uk ESA.int ScienceAlert.com

radiation earth glitch space collapse technology satellites GPS scientific cosmos information technology computing magnetic shield