The Earth’s magnetic field, one of the primary reasons life persists on the planet, acts as a protective shield that safeguards the atmosphere and the Earth’s surface from cosmic radiation and charged particles from the sun. This field is generated by the movement of molten liquid iron within the Earth’s outer core, approximately 3,000 kilometers beneath the surface. The moving iron functions like a gigantic electric generator, producing electric currents that create magnetic field lines wrapping around the planet and forming its protective shield.
However, the precise processes governing this complex system remain mysterious and are being studied using advanced space technologies. Thanks to data from the three satellites of the Swarm mission, launched by the European Space Agency in 2013 to accurately measure magnetic changes, scientists have discovered that the weak area above the South Atlantic Ocean, known as the South Atlantic Anomaly, has expanded significantly. According to a study published in the journal “Physics of the Earth and Planetary Interiors,” this area has increased in size since 2014 by nearly half the size of continental Europe.
Chris Finlay, the lead researcher from the Technical University of Denmark, states, “The South Atlantic Anomaly is not a uniform region; it evolves differently in its parts near Africa compared to South America. Something unusual is happening in this area that causes the magnetic field to weaken at a faster pace.” Researchers link this disturbance to changes occurring at the boundary between the Earth’s liquid outer core and the rocky mantle, where magnetic flow patterns in this deep layer are believed to be changing in an unusual manner.
Finlay explains, “Normally, magnetic field lines exit from the core in the Southern Hemisphere, but in the anomaly region, we observe the opposite phenomenon – some field lines return to the core instead of exiting.” He added that satellite data also revealed the movement of one of these weak areas westward over the African continent, contributing to the anomaly’s expansion.
Recent measurements indicate that the magnetic field over Siberia has become stronger, while it has weakened over Canada, a volatile balance that could impact navigation and communication systems relying on satellites. Scientists warn that the weakened magnetic field over the South Atlantic makes satellites in low orbit vulnerable to higher doses of cosmic radiation, increasing the likelihood of technical malfunctions and signal interruptions.
Moreover, astronauts and spacecraft, including those on the International Space Station, are exposed to higher levels of radiation when passing through this weak area. Although scientists do not anticipate an imminent collapse of the magnetic field, the expansion of the current weak zone suggests that Earth’s protective shield is undergoing a phase of dynamic change, the causes of which are not yet fully understood.
Researchers emphasize that continued monitoring of satellite data over the coming years will be crucial to understanding how this anomaly develops – and whether it’s merely a temporary phenomenon or the beginning of a broader transformation in the planet’s magnetic field.
