NASA deciphers the unpredictable drift of magnetic anomaly
NASA is tracking the South Atlantic Anomaly (SAA), an unusual phenomenon in Earth's magnetic field characterized by a weakened magnetic field. Scientists are interested in and concerned about this region, which has particular significance for satellites and spacecraft exposed to solar radiation in the anomaly area.
NASA describes the SAA as a "dent" in Earth's magnetic field. The SAA does not directly affect life on Earth. However, satellites orbiting at low altitudes, including the International Space Station (ISS), regularly pass through this region. This can lead to electronic system failures. Interactions with high-energy protons from solar radiation can damage and even permanently fail these systems.
Anomaly in Earth's magnetic field
According to Science Alert, satellite operators often shut down sensitive systems during passages through the anomaly to minimize the risk of data loss or significant damage. NASA is actively monitoring the phenomenon to develop ways to mitigate risks and better understand its nature.
In 2020, Terry Sabaka from the Goddard Space Flight Center noted that the anomaly is caused by a complex interaction of magnetic fields generated by various sources. The main source is the movement of liquid iron in Earth's outer core, which generates electric currents responsible for creating the magnetic field.
Additionally, a large mass of dense rocks known as the "large low shear velocity province" (LLSVP), located about 2,900 kilometres under the surface of Africa, may be disrupting this process. NASA suggests that the weakening of the magnetic field in this region is likely also the result of local fields with reversed polarity.
NASA research indicates that the SAA is not static. In 2016, a team led by Ashley Greeley discovered that the anomaly was slowly drifting westward. Furthermore, research from 2020 showed that the anomaly is beginning to split into two parts, creating two separate centres of minimum magnetic field intensity. Additionally, analyses suggest that the SAA is not a new phenomenon.
Science Alert reminds us that a study published in July 2020 indicates that similar anomalies may have occurred on Earth as far back as 11 million years ago. This discovery challenges the theory that the current anomaly is a precursor to a global magnetic pole reversal, which occurs every few hundred thousand years. Scientists still have many questions about the SAA and the phenomenon's future. They believe it could provide valuable insights into the evolution of Earth's magnetic field and its impact on technology and life on Earth.
