NASA warns of a planetary anomaly traced to mysterious forces beneath Earth’s crust

In recent years, scientists have raised alarms about an increasingly unpredictable anomaly in Earth’s magnetic field, and it’s not just a quirky phenomenon. The South Atlantic Anomaly (SAA), a massive region stretching from parts of South America to the South Atlantic Ocean, poses serious challenges to space-based technology. NASA has been closely monitoring the anomaly, which is weakening the magnetic shield that normally protects us from the sun’s energetic particles¹.

Did you know? Satellites in low Earth orbit can encounter radiation levels up to ten times higher when passing through the SAA compared to other regions.

For years, Earth’s magnetic field has deflected harmful solar radiation. However, in the SAA, this barrier thins, allowing high-energy particles to penetrate deeper into the atmosphere than usual and creating significant risks for satellites, the International Space Station and other equipment relying on a stable magnetic environment.

The origins: Geodynamics beneath our feet

The SAA’s roots lie in complex geodynamic processes deep within Earth’s core. At about 2,890 km below the surface, molten iron and nickel circulate in the outer core in a process known as the geodynamo, generating our planet’s magnetic field. These flows aren’t uniform: the tilt between Earth’s magnetic and rotational axes, combined with the dense African Large Low Shear Velocity Province beneath Africa, disrupts local field generation and may have caused a partial magnetic reversal that weakens the field over the South Atlantic².

Space technology at risk: Satellite malfunctions on the rise

This weakened field exposes satellites to much higher levels of energetic protons, which can trigger single event upsets (SEUs)—temporary glitches, data corruption or, in extreme cases, permanent hardware damage. According to NASA engineers, instruments aboard the ISS lose several hours of scientific data each month due to system resets after passing through the SAA. To mitigate these risks, agencies often power down non-essential systems during each transit and adjust operational schedules for missions like the Ionospheric Connection Explorer (ICON).

The anomaly evolves: Two centers of minimal magnetic intensity

The SAA is not static. Data from ESA’s Swarm satellites and NASA’s historic SAMPEX mission show the anomaly expanding and bifurcating into two lobes—each zone marking a local minimum in field strength. This split increases the number of vulnerable corridors for space systems and complicates predictions of the anomaly’s future shape and intensity.

Simulations and monitoring: Efforts to understand the SAA

To stay ahead, researchers fuse satellite observations with advanced simulations of Earth’s core dynamics. Feeding these data into global reference models such as the International Geomagnetic Reference Field (IGRF) lets scientists forecast magnetic-field changes over years and decades, much like meteorologists predict weather patterns³. While the current SAA evolution is unprecedented in the space-era, geological records suggest similar anomalies have occurred over hundreds of thousands of years—but they are not harbingers of an imminent full pole reversal.

The future: Preparing for an evolving magnetic environment

As the South Atlantic Anomaly continues to grow and shift, ongoing international collaboration and adaptive engineering will be vital. Satellite designers must incorporate dynamic shielding strategies, and mission controllers will need real-time anomaly maps to plan safe orbits. Understanding the SAA not only protects our technological assets but also offers a rare window into the hidden workings of Earth’s deep interior.

Footnotes :

1. South Atlantic Anomaly: 2015 through 2025, NASA Scientific Visualization Studio, https://svs.gsfc.nasa.gov/4840/

2. African Large Low‐Shear‐Velocity Province and the Earth’s magnetic field, Nature Geoscience, https://www.nature.com/articles/ngeo2839

3. International Geomagnetic Reference Field, NOAA, https://www.ngdc.noaa.gov/IAGA/vmod/igrf.html