Growing Weak Point In Earth’s Magnetic Field At Least 11 Million Years Old

A team of scientists has identified the estimated age of the weakest point in Earth’s magnetic field. The current status of this region in the magnetosphere has led to speculations that a polar reversal could happen soon.

The magnetic field is a protective layer that shields Earth from cosmic radiation and the high-energy emissions from the Sun. Since the magnetic field is affected by the movement of the Earth’s liquid core, it is dynamic and can occasionally get stronger and weaker over time.

For their study, the scientists focused on a region in the magnetic field known as the South Atlantic Anomaly (SAA). This region, which spans over South America to Africa, has been identified as the weakest point in Earth’s magnetic field.

According to previous observations, satellites that pass under the SAA get more exposed to radiation compared to other parts of the magnetic field.

“Other anomalies exist in the magnetic field,” scientist Yael Engbers of the University of Liverpool told Newsweek. “However, the South Atlantic Anomaly is the most extreme and most of all the biggest anomaly causing the field to be weaker, which causes the Earth, our atmosphere and our technology to be vulnerable to charged particles from the Sun.”

According to previous studies, the SAA has been growing for the past 50 years. Due to the expansion of the weak point in the magnetic field, some scientists speculated that it could trigger a polar reversal soon.

To determine if the SAA could trigger a reversal, scientists analyzed its age by studying volcanic rocks from eruptions that occurred around 8 million to 11 million years ago. Since lava becomes magnetized in the direction of the magnetic field when it solidifies, it can provide clues regarding the status of the magnetosphere when it was formed.

Through their observations, the scientists learned that volcanic rocks showed varying levels of magnetic field direction, suggesting that they were affected by the presence of the SAA. This finding led the scientists to conclude that the SAA may be around 11 million years old.

The scientists explained that the age of the SAA implies that it is not in danger of causing a polar reversal.

“Our data shows that over a time span of millions of years there has been irregular field behavior in the South Atlantic region,” Engbers stated. “This implies that the current situation is not as rare as some scientists had assumed, making it less likely that it represents the start of a much more rare reversal.”

The scientists presented their findings in a study published in the journal Proceedings of the National Academy of Sciences of the United States of America.