(ORDO NEWS) — NASA is actively monitoring a strange anomaly in Earth‘s magnetic field: a giant area of lower magnetic strength in the sky above the planet, stretching between South America and southwest Africa.
This is a broad, evolving phenomenon, called the South Atlantic Anomaly, has been intriguing and worrying scientists for years, and perhaps no more than NASA researchers.
The space agency’s satellites and spacecraft are particularly vulnerable to weakened magnetic field strengths within the anomaly, and the consequent impact of the Sun’s charged particles.
The South Atlantic Anomaly (SAA), which NASA likens to a “dent” in the Earth’s magnetic field or a kind of “pocket in space” – usually does not affect life on Earth, but the same cannot be said for orbiting spacecraft (including the International Space Station), which pass directly through the anomaly, orbiting the planet at low Earth orbit altitudes.
During these collisions, the reduced magnetic field strength inside the anomaly means that technological systems aboard the satellites could fail if they were hit by high-energy protons emanating from the Sun.
These accidental hits can usually cause only minor disruptions, but they carry the risk of significant data loss or even permanent damage to key components threats that require satellite operators to routinely shut down spacecraft systems before the spacecraft enters the anomaly zone.
Mitigating these dangers in space is one of the challenges. the reason NASA is tracking the SAA; the other is that the mystery of the anomaly presents an excellent opportunity to investigate a complex and difficult to understand phenomenon, and NASA’s extensive resources and research teams are uniquely positioned to study this phenomenon.
“The magnetic field is actually a superposition of fields from many current sources,” explained geophysicist Terry Sabaka of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, in 2020.
The primary source is thought to be a seething ocean of molten iron within the Earth’s outer core, thousands of kilometers underground.
The movement of this mass generates electric currents that create the Earth’s magnetic field, but it does not seem to be necessarily uniform.
A huge reservoir of dense rock, called the African Great Low Shear Province, located about 2,900 kilometers (1,800 miles) below the African continent, disrupts field generation, resulting in a dramatic weakening effect, aided by the tilt of the planet’s magnetic axis.
“The observed SAA can also be interpreted as a consequence of the weakening of the dominance of the dipole field in the region,” said NASA Goddard geophysicist and mathematician Weijia Kuang in 2020.
“In particular, the localized field with reverse polarity grows strongly in the SAA region, which makes the field intensity very weak, weaker than that of the surrounding regions.”
Although many scientists still do not fully understand the anomaly and its consequences, new ideas are constantly shedding light on this strange phenomenon. .
For example, one study by NASA heliophysicist Ashley Greeley in 2016 found that the SAA is slowly drifting in a northwesterly direction.
However, this is not just a movement. Even more remarkable, the phenomenon appears to be in the process of splitting into two: in 2020, researchers found that the SAA appears to be splitting into two separate cells, each representing a separate center of minimum magnetic intensity. within the larger anomaly. p>
What this means for the future of the SAA remains unknown, but in any case, there is reason to believe that the anomaly is nothing new.
A study published in July 2020 suggests this phenomenon is not an unusual recent event, but a recurring magnetic phenomenon that may have affected the Earth as early as 11 million years ago.
If so, this could mean that the South Atlantic Anomaly is not the trigger or precursor to a planet-wide reversal of the magnetic field, which is actually happening, if not hundreds of thousands of years at a time.
Obviously, huge questions remain, but with so much to do with this huge bizarre magnetic oddity, it’s good to know the world’s most powerful space agency in our country is watching it as closely as they do.
“Even though the SAA is moving slowly, it is undergoing some changes in morphology, so it is also important that we continue to monitor it as we continue our missions,” Sabaka said.
“Because it helps us build models and make predictions.”
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