Currently, scientists are tracking major shifts in the Earth’s magnetic field. This vital component is an important driver of every productive ecosystem on land and in the ocean. Found deep under the Earth’s surface, nearly 2,000 miles down, a churning sea of liquid iron creates this magnetic field. Its complexity is much greater than the dipole, such as a bar magnet. Continuing research indicates that the South Atlantic Anomaly, a natural, weak region in the magnetic field, has grown drastically since 2014. This rapid expansion has left researchers scrambling to catch up.
Scientists originally discovered the South Atlantic Anomaly in the 19th century, located southeast of South America. Today, it stretches across an area almost the size of continental Europe. This area is very important when it comes to space safety, since satellites passing through this area are subjected to much stronger radiation. Meanwhile, contrasting changes have been noted in other parts of the world, including strengthening fields over Siberia and weakening fields over Canada.
Understanding Earth’s Magnetic Field
The Earth’s magnetic field is an important, global asset that protects the planet from hazardous solar and cosmic radiation. These movements create an intense magnetic force that creates a protective barrier. There, liquid iron moves in complex patterns, generating intense lines of magnetic force. The magnetic field is not nearly as simple as a bar magnet. It includes a detailed map of the different regions’ magnetic strengths, from strong to weak.
Chris Finlay, a scientist who’s been deeply involved in studying these changes, makes the case for understanding this complexity.
“When you’re trying to understand Earth’s magnetic field, it’s important to remember that it’s not just a simple dipole, like a bar magnet. It’s only by having satellites like Swarm that we can fully map this structure and see it changing.” – Chris Finlay
For scientists, satellite technology has been nothing short of revolutionary. The European Space Agency’s Swarm mission is tremendously important in helping them watch and understand these changes as they happen in real-time. The data gathered provides a complete picture of the complex, sometimes chaotic, processes occurring deep within the Earth’s core.
Expansion of the South Atlantic Anomaly
Scientists are looking at the South Atlantic Anomaly due to its increasing area. This phenomenon has far-reaching consequences for technology operating in the space environment. Since 2014, this crevice has expanded substantially, posing serious risks for satellites that travel through it. The magnetic anomaly itself is defined by localized structures where magnetic field lines have erratic and chaotic trajectories.
“Normally we’d expect to see magnetic field lines coming out of the core in the southern hemisphere. But beneath the South Atlantic Anomaly we see unexpected areas where the magnetic field, instead of coming out of the core, goes back into the core.” – Chris Finlay
With this weirdness set to grow, scientists have been studying what it might mean for satellites in orbit and technology here on Earth. A surge of additional radiation could fry delicate electronic circuitry on spacecraft and even endanger the lives of astronauts.
Regional Variations in Magnetic Field Strength
As the South Atlantic Anomaly grows, other areas of the globe and even the oceans show much stronger magnetic fields growing at a significantly different rate. Not cavernous at all, actually—just over Siberia the magnetic field has unexpectedly strengthened since 2013. That is an increase of about the equivalent of 0.42% of the entire surface area of the Earth—roughly the area covered by the island of Greenland. In contrast, Canada’s strong field region has weakened, shrinking by 0.65% of Earth’s surface area—an area nearly equivalent to that of India.
The strange geology at work in these areas are telling signs of weird and fascinating developments going on right beneath our feet in Earth’s liquid metal core. These changes continue to document an increase in the strength of magnetism. Such changes might affect AUG magnetosphere-shielded subsequent navigation systems and other emerging technologies that rely on unadulterated magnetic fields.
“It’s really wonderful to see the big picture of our dynamic Earth thanks to Swarm’s extended timeseries,” said Anja Stromme from ESA. “The satellites are all healthy and providing excellent data, so we can hopefully extend that record beyond 2030, when the solar minimum will allow more unprecedented insights into our planet.”