Auroras have weakened in the Southern Hemisphere due to a strange anomaly in Earth’s magnetic field

The South Atlantic Magnetic Anomaly (AMAS) is an oval-shaped area in which the magnetic force is notably weaker. According to a new study, this deformation in the Earth’s magnetic field, located in the north of South America and south of the Atlantic Ocean, weakens the auroral lights in this region. The study, published in February in the journal Geophysical Research Lettersgoes beyond all previous research carried out on the topic, as it seeks to understand the effects of the anomaly on the Earth’s aurora system.

The Southern Lights occur over and around Antarctica, similar to the Northern Lights in the Arctic and Subarctic zones. Auroras are caused by the interaction of solar particles with gas molecules in Earth’s atmosphere.

The South Atlantic Magnetic Anomaly was already known to allow some particles from the Sun to come close to the Earth’s surface, exposing satellites orbiting in that space to high levels of ionizing radiation, according to NASA. Zhi-Yang Liu, lead author of the study and researcher at the Beijing Institute of Space Physics and Applied Technology, considers magnetic anomalies like AMAS to be essential for a comprehensive understanding of planetary auroral systems.

Scientists used data from an instrument – ​​used to measure variations in high-frequency magnetic fields – that was on board the FengYun-3E satellite, present in Earth’s orbit at an altitude of 836 km, since 2021. Based on information collected at Over the course of two years, researchers discovered a substantial weakening of magnetic oscillations in the southern auroras, exactly in the region overlapping the deformation found.

In order to confirm the results obtained, the scientists also analyzed the ultraviolet light from the site under study using data from the United States Department of Defense’s Meteorological Satellite System. The weakening of the auroras was thus confirmed and can even be seen with the naked eye, says Liu.

Study co-author Qui-Gang Zong, also from the Institute of Space Physics and Applied Technology, suggests that ultraviolet light and the light that is visible in the auroras work in a similar way, and hence the possibility that the weakening of the auroras caused by by the South Atlantic Anomaly.

The researchers add that magnetic fluctuations weakened by the anomaly appear to reduce the amount of energy that can be put into the atmosphere by solar particles, but the physics of this phenomenon is not yet fully understood.