According to NASA, Earth’s magnetic field has a weak spot called the South Atlantic Anomaly, named after its location somewhere over South America and the southern Atlantic Ocean, this small but evolving dent in Earth’s magnetic field can cause big headaches for satellites.
Scientists at NASA are investigating the mysterious anomaly, a region of weakness in the Earth’s magnetic field that is growing in size. Particle radiation in this region can knock out onboard computers and interfere with the data collection of satellites that pass through it. South Atlantic Anomaly is also of interest to NASA’s Earth scientists who monitor the changes in magnetic field strength, both for how such changes affect Earth’s atmosphere and as an indicator of what’s happening to Earth’s magnetic fields, deep inside the crust. South Atlantic Anomaly arises from two features of Earth’s core: The tilt of its magnetic axis, and the flow of molten metals within its outer core. As the core motion changes over time, due to complex geodynamic conditions within the core and at the boundary with the solid mantle up above, the magnetic field fluctuates. These dynamical processes in the core ripple outward to the magnetic field surrounding the planet, generating the South Atlantic Anomaly.
Although the South Atlantic Anomaly arises from processes inside Earth, it has effects that reach far beyond Earth’s surface. The region can be hazardous for low-Earth orbit satellites that travel through it. If a satellite is hit by a high-energy proton, it can short-circuit and cause an event called single event upset or SEU. This can cause the satellite’s function to glitch temporarily or can cause permanent damage.
The changing South Atlantic Anomaly provides researchers new opportunities to understand Earth’s core, and how its dynamics influence other aspects of the Earth system. To keep tabs on future challenges that could arise, space agencies like European Space Agency and NASA keep tabs on the magnetic field’s weakening.