The Earth’s suit of geomagnetic armor has a slit and is growing.
A weak point in our planet’s magnetic field, located over the South Atlantic Ocean, has increased in size over the past two centuries and is beginning to split in two.
For those of us on earth, this is not a cause for concern: the protective field continues to protect the planet from deadly solar radiation.
But the South Atlantic anomaly, as it is aptly called, affects satellites and other spacecraft passing through an area between South America and southern Africa.
This is because there are higher amounts of solar particles charged by the field there, which can cause malfunctions in computers and circuits.
The source of this growing “dentate,” as NASA calls it, is a bit mysterious. But scientists expect it to continue to expand.
“This thing will increase in size in the future,” Julien Aubert, an expert in geomagnetism at the Paris Institute of Earth Physics, told Insider.
Aubert believes the pier may have a connection to two giant dense rock bubbles buried 2,897 kilometers (1,800 miles) inland. Due to their makeup, the stains disrupt the liquid metal in the outer core that generates the magnetic field.
Both bubbles are “millions of times larger than Everest in terms of volume,” according to Qian Yuan, a researcher studying geodynamics at Arizona State University.
Yuan’s team believes the blobs have an extraterrestrial origin: after an ancient planet the size of Mars entered Earth, it might have left these pieces behind.
Pieces of a planet 4.5 billion years old on Earth
Nearly 3,219 kilometers below the Earth’s surface, the swirling iron in the outer core of the planet generates a magnetic field that extends from there to the space surrounding our planet.
This eddy is generated, in part, by a process in which the warmest, lightest material in the core rises to the semi-solid mantle above. There, it exchanges places with cooler, denser mantle material, which sinks into the lower core. This is known as convection.
The problem is that something at the boundary between the core and the mantle beneath southern Africa is wreaking havoc on this convection, thus weakening the strength of the magnetic field above.
It is plausible, Aubert said, that one of the blobs investigating Yuan’s team is the culprit.
Yuan’s research suggests that the spots are remnants of an ancient planet called Theia, which whipped the Earth in its beginnings 4.5 billion years ago. The collision helped create the Moon.
After this collision, it is thought, two parts of Theia may have sunk and been preserved in the deepest part of the Earth’s mantle.
The following animation, based on a 2016 analysis, shows the location of these planetary fragments.
(Sanne.cottaar / WikimediaCommons / CC-BY-4.0)
Yuan said that these bubbles (their technical name is large provinces of low shear rate) are between 1.5 and 3.5 percent denser than the rest of the Earth’s mantle and are also hotter.
Thus, when these pieces are involved in convection, they could be screwed with regular flow. This, in turn, can cause the iron in the core in southern Africa to turn in the opposite direction to the iron in other parts of the core.
The orientation of the Earth’s magnetic field depends on the direction in which the iron moves inward. To have a strong magnetic field, everything must be oriented in the same way. Therefore, any area that deviates from the usual pattern weakens the overall integrity of the field.
Still, it is possible that these low-speed provinces are not to blame for the weak point of the field.
“Why doesn’t the same weakness occur in the magnetic field over the Pacific, where the other province is?” Christopher Finlay, a geophysicist at the Technical University of Denmark, told Insider.
A “hostile region”
A weaker field allows more particles charged by the solar wind to reach satellites and other spacecraft in low Earth orbit. This can cause problems with electronic systems, disrupt data collection, and cause expensive computer components to age prematurely.
In the 1970s, 1980s and 1990s, satellite failures were frequent in the South Atlantic anomaly, Aubert said.
Even today, the European Space Agency has found that satellites flying through the region are “more likely to suffer technical malfunctions,” such as brief errors that can disrupt communications.
Therefore, it is common for satellite operators to close non-essential components as objects pass through the area.
The Hubble Space Telescope also traverses the anomaly in 10 of its 15 orbits around the Earth each day and spends nearly 15% of its time in this “hostile region,” according to NASA.
The weak point becomes weaker
Researchers use a set of three satellites, collectively called Swarm, to monitor South Atlantic anomalies.
Some studies suggest that the total area of the region has quadrupled in the last 200 years and continues to increase year after year. The anomaly has also weakened by 8% since 1970.
In the last decade, Swarm also observed that the anomaly has split in half: one area of magnetic weakness has developed over the ocean in southwest Africa, while another is in eastern South America.
This is bad news, according to Finlay, because it means the hostile region of spacecraft will increase.
“Satellites will have problems not only in South America, but they will also be affected when they reach southern Africa,” he said.
This article was originally published by Business Insider.
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