Often referred to as the “Bermuda Triangle of Space,” the magnetic field in the South Atlantic dates back millions of years. A new study provides the first long-term analysis of the phenomena, revealing that the anomaly in the magnetic field in the South Atlantic is not a unique event –similar anomalies existed eight to 11 million years ago as part of a pattern lasting for over 1,000 years. characterized by a significant reduction in the strength of Earth’s magnetic field compared with areas at similar geographic latitudes.
This invisible force field doesn’t just give us our north and south poles; it’s also what protects us from solar winds and cosmic radiation – but is rapidly weakening, to the point some scientists speculate it could actually flip, with our magnetic poles reversing. The last reversal of the poles towards today’s orientation took place 780,000 years ago. Earth’s magnetic field serves as a shield against dangerous radiation from space, especially the Sun’s charged particle flux.
The Long View
“This is the first time that the irregular behavior of the geomagnetic field in the South Atlantic region has been shown on such a long timescale,” said Yael Engbers who led the study at the University of Liverpool about the phenomenon that today creates technical malfunctions aboard satellites and spacecraft. It suggests that the South Atlantic Anomaly is not a sign of an impending magnetic-field reversal.
The Liverpool study was preceded in 2018 by a reconstruction of the Earth’s magnetic field of the past, where scientists from the Helmholtz Centre Potsdam – GFZ German Research Centre for Geosciences and the Universities of Iceland, Liverpool, and Nantes showed that the anomaly is not a precursor of a switching of the poles.
The Laschamp Excursion –A Harbinger?
Based on observations of the past 50,000 years the GFZ team concluded that the South Atlantic Anomaly cannot be interpreted as a sign for the beginning of a reversal of the poles, said Monika Korte. “Times of the past that, unlike the beginning of the Laschamp excursion, showed patterns of the magnetic field like today were not followed by a pole reversal. After some time the anomalies disappeared.” 41,000 years ago, the Earth’s magnetic field switched polarity for less than one thousand years, the so-called Laschamp excursion with the pole eventually returning to its original polarity.
The Hubble video below tells the story of what happens to the Hubble Space Telescope when it in the mysterious region and is bombarded with swarms of intensely high energy particles, producing produce ‘glitches’ in astronomical data, malfunctioning of on-board electronics, and shut down spacecraft for weeks.
“It also supports earlier studies that hint towards a link between the South Atlantic Anomaly and anomalous seismic features in the lowermost mantle and the outer core,” Engbers added about the results of paleomagnetic researchers who analysed the record of Earth’s magnetic field which is preserved in igneous rocks from the island Saint Helena which lies in the midst of the South Atlantic Anomaly. “This brings us closer to linking behavior of the geomagnetic field directly to features of the Earth’s interior”.
The geomagnetic records from the rocks covering 34 different volcanic eruptions that took place between eight and 11 million years ago revealed that at these occurrences the direction of the magnetic field for St Helena often pointed far from the North pole, just like it does today.
The Earth’s magnetic field, or the geomagnetic field, not only gives us the ability of navigating with a compass, but also protects our atmosphere from charged particles coming from the sun, called solar wind. However, it is not completely stable in strength and direction, both over time and space, and it has the ability to completely flip or reverse itself with substantial implications.
The South Atlantic Anomaly is still a topic of hot debate between scientists in this field. Besides the fact that it causes damages to space technology, it also raises the question of where it comes from and whether it represents the start of the total weakening of the field and a possible upcoming pole reversal.
Source: Elevated paleomagnetic dispersion at Saint Helena suggests long-lived anomalous behavior in the South Atlantic, Proceedings of the National Academy of Sciences (2020). DOI: 10.1073/pnas.2001217117
The Daily Galaxy, Max Goldberg, via by University of Liverpool