Massive ‘weak spot’ in Earth’s magnetic area is rising… and it may have enormous penalties
Scientists have discovered that the ‘weak spot’ in Earth’s magnetic field has grown to more than 4.3 million square miles, larger than Canada.
That is a seven percent increase from 2020 when researchers first sounded the alarm about the South Atlantic Anomaly (SAA), a region in the magnetic field of reduced intensity over Africa and South America.
The ‘dent’ allows harmful radiation particles from the sun to seep through the weak area of our planet’s magnetic field, which NASA has warned ‘can knock out onboard computers and interfere with the data collection of satellites that pass through it.’
SAA’s center has also moved 12 miles westward since 2020, suggesting the region will continue to shift towards the eastern Pacific Ocean.
While scientists believe that the SAA’s weakening magnetic intensity is still within the range of normal variation, recent studies have shown that it is starting to split from a single blob into two distinct regions of minimal magnetic field strength.
Models predicting changes in the SAA suggest this division will continue from 2025 onward, and scientists believe this could create additional challenges for satellite missions.
Researchers have speculated that the weakening is a sign that Earth is heading to a pole reversal that happens when the north and south poles switch places — and the last time this occurred was 780,000 years ago.
They said that if the poles are in the process of reversing, it will happen over several thousand years and it is unlikely the field will disappear completely.
NASA has been monitoring the South Atlantic Anomaly, a weak-spot in Earth’s magnetic field sitting 40,000 miles above the planet’s surface between South America and southwest Africa
Scientists first sounded the alarm about the weak spot in 2020, but new data shows it has increased by another seven percent over the past four years
The cause of SAA sits deep within 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 Centre in Greenbelt, Maryland explained in a 2020 statement.
While regions outside of Earth contribute to the observed magnetic field, the primary source stems from inside the planet.
The outer layer of Earth’s core is made of molten iron and nickel located 1,800 miles below the surface.
These churning metals act like a massive generator called the ‘geodynamo,’ creating electric currents that produce the magnetic field.
But this motion isn’t constant. It fluctuates over time, and as a result, Earth’s magnetic field fluctuates too.
This, coupled with the tilt of the planet’s magnetic axis, is what produces the SAA, according to NASA.
But scientists have also suggested the SAA could be linked to a huge reservoir of dense rock known as the African Large Low Shear Velocity Province (LLSVP). The area of the anomaly appears to correspond to that of this geologic region.
The magnetic field surrounding our planet works as a shield, trapping and repelling particles of radiation from the sun. But the SAA allows radiation to come closer to Earth’s surface
These researchers believe that the African LLSVP changes the flow of molten metal in the outer core underneath, which in turn changes the way the magnetic field behaves above this region, they explained in a 2017 article for the Conversation.
While much remains unknown about how the SAA came to be, recent studies have shed new light on how it is changing.
Tracking conducted by small satellites known as CubeSats confirmed that the SAA does not remain fixed in one place, but rather drifts around.
Researchers have also discovered that the anomalous region is splitting into two, with each representing distinct centers of minimum magnetic intensity within the greater SAA.
And another study suggested that this phenomenon is actually a recurrent event that may have affected Earth up to 11 million years ago.
If that proves true, this would contradict the idea that the SAA is a precursor to Earth’s magnetic field flipping.
This vast, developing weak spot is a point of intrigue and concern for scientists, especially those at NASA whose satellites and orbital spacecraft can be significantly damaged by the SAA — including the International Space Station.
When these orbiters pass through the anomaly, it can cause satellites and spacecraft to experience short-circuits and malfunctions.
That’s because the reduced strength of Earth’s magnetic field allows the orbiters to be pummeled by incoming solar radiation that disrupts technological systems.
Typically, this only causes low-level glitches. But in extreme cases, it can permanently damage critical hardware inside an orbiter.
To avoid such damage, operators regularly shut down spacecraft and satellite systems before they enter the SAA.
The weakened field has been on the radar of experts for years — they know that it has lost nine percent of its intensity over the last 200 years.
It also appears to influence the strength of the southern aurora, a natural light display that occurs in the skies over the high-latitude regions of the southern hemisphere.
A study published in the journal Geophysical Research Letters in February found a ‘substantial weakening’ of magnetic fluctuations in the southern aurora where it overlaps with the SAA.
This weakening is even visible to the naked eye, the study’s authors told Live Science.
They believe the weakened magnetic force of the anomaly reduces the amount of energy solar particles can put into Earth’s atmosphere — which is what causes aurora — even through more of these particles are coming close to the surface.
To further understand how the SAA impacts orbiting satellites and spacecraft, and how it influences geophysical phenomena like the southern aurora, NASA scientists have been monitoring it for years.
