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NASA claims that the "dent" allows harmful solar radiation particles to enter through the weak point in the magnetic field of our planet.
The "weak area" in Earth's magnetic field is expanding, allowing dangerous radiation to approach the surface of our planet, according to NASA scientists.
The area, referred to as the South Atlantic Anomaly (SAA), is expanding westward and covers more than 4.3 million square miles across portions of South America and Africa. According to NASA, the "dent" permits dangerous solar radiation particles to penetrate the weak spot in our planet's magnetic field, which "may knock out onboard computers and interfere with the data collecting of satellites that pass through it."
Since analysts first raised the danger in 2020, the SAA has expanded by 7% and shifted 12 miles west. Recent studies have revealed that the SAA is beginning to separate from a single blob into two different zones of limited magnetic field strength, however scientists still feel that the SAA's declining magnetic intensity is within the range of normal variation.
According to models projecting changes within the SAA, this separation is expected to persist starting in 2025, which experts fear may provide new difficulties for satellite missions.
The weakening, according to researchers, is an indication that Earth is about to undergo a pole reversal, which occurs when the north and south poles alternate positions. This last happened 780,000 years ago. According to them, it is doubtful that the field will entirely vanish if the poles are reversing; this process will take place over a period of several thousand years.
The cause of SAA is deep beneath the Earth's surface. "The magnetic field is actually a superposition of fields from many current sources," geophysicist Terry Sabaka from NASA's Goddard Space Flight Center in Greenbelt, Maryland, noted in a 2020 statement.
Although the observed magnetic field is influenced by areas outside of Earth, the planet itself is the main source. Molten iron and nickel make up the outermost layer of the Earth's core, which is 1,800 miles below the surface. The "geodynamo," a huge generator made of these churning metals, generates the electric currents that generate the magnetic field.
However, this motion is not continuous. Over time, it changes, which causes the Earth's magnetic field to change as well. NASA says this, along with the tilt of the planet's magnetic axis, creates the SAA.
However, researchers have also hypothesized that the African Large Low Shear Velocity Province (LLSVP), a massive store of dense rock, may be connected to the SAA. This geologic region seems to be the same size as the anomaly's area.
In a 2017 article for the Conversation, these researchers revealed that they think the African LLSVP alters the flow of molten metal in the outer core below, which alters the behavior of the magnetic field above this region. The origins of the SAA are still mostly a mystery, but new research has provided insight into how it is evolving.