This curious anomaly in the Earth's magnetic field impacts auroras and our satellites

The South Atlantic Anomaly, a vast region located above South America and the South Atlantic Ocean where the Earth's magnetic field is particularly weak, is catching the attention of researchers. This area allows charged particles from the Sun to approach closer to the Earth's surface, thus exposing satellites in orbit to a high level of ionizing radiation.


This magnetic field weakness is not just a geophysical curiosity. It has a direct impact on the southern auroras, those dances of lights occurring in the Earth's atmosphere around Antarctica. These auroras are the result of the encounter between solar particles and gases in our atmosphere. A recent study published in the journal Geophysical Research Letters shows that the South Atlantic Anomaly weakens these southern lights, altering their usual intensity.


Researchers have used satellite data to study this phenomenon. They observed that where the South Atlantic Anomaly overlaps with the southern auroras, the intensity of these lights decreases. This weakening could even be noticeable to the naked eye, a statement supported by the fact that fewer auroras are reported in some Antarctic research stations located in or near this anomaly.

This highlights an aspect: auroras, although often thought to be mainly influenced by the Sun, are also affected by Earth-related factors, such as variations in its magnetic field. The South Atlantic Anomaly reduces the amount of energy that solar particles can transfer to the atmosphere, which decreases the intensity of the auroras.


This phenomenon is not just a curiosity for scientists; it reminds us how closely we are connected to our planet and the surrounding space, especially for our technology. Future research might reveal if similar phenomena affect other planets, broadening our understanding.