Earth's magnetic 'hole' is expanding and shifting. Should we be worried?

An anomalous region in Earth's magnetic field is showing signs of change, ones that might not bode well for the planet. According to a study, the weak spot in the field, known as the South Atlantic Anomaly (SAA), is growing and shifting. It has grown to twice the size of Texas since 2014, and has shifted westward towards Africa. Researchers say that this weak zone moves about 22 kilometres every year, and has seen a 25 per cent increase in size. Earth's magnetic field is created by the molten iron in Earth’s outer core. As it swirls around at a depth of thousands of kilometres, it creates a protective zone around the planet that protects us from the harmful cosmic radiation and the harmful particles unleashed by the sun. But it doesn't generate an equal layer everywhere.

Scientists studied 11 years of data from the European Space Agency’s (ESA) Swarm satellite constellation to figure out what's happening with Earth’s magnetic field. Lead author Chris Finlay, Professor of Geomagnetism at the Technical University of Denmark, said in a statement that this change is happening "differently towards Africa than it is near South America." He said, "There's something special happening in this region that is causing the field to weaken in a more intense way." A fluctuation in Earth's magnetic field is not uncommon. As the movement of the molten iron 2,896 kilometres below the surface fluctuates, the magnetic field witnesses changes too. According to NASA, when this phenomenon is coupled with the tilt of the planet's magnetic axis, an anomaly is created, which is known as the SAA.

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Molten iron inside the Earth is changing the magnetic field

The South Atlantic Anomaly is a zone where the magnetic field is weaker. The molten iron moves turbulently inside Earth, and this swishing around has resulted in the expansion and shifting of the SAA. How does a weakening and shifting magnetic field affect humans and the man-made objects in space? According to the study, it can have repercussions on the satellites and astronauts in space. The phenomenon exposes spacecraft to higher levels of radiation, affecting their functioning. Electronics can be disrupted temporarily, while permanent damage to critical hardware is also a possibility. This will affect activities on Earth, as these satellites are crucial for GPS and weather forecasting services. So when these spacecraft pass through this weak anomalous zone, they can malfunction from the radiation.

Talking about the shifts in the magnetic field, the scientists noted that in the southern hemisphere, weak magnetic areas under Africa are moving westward, while similar regions in the mid-Atlantic are moving east. In the north, there is a strong magnetic zone under the Bering Strait, which is drifting west, and near Indonesia and the western Pacific, magnetic features are moving east. While humans on Earth might not be directly impacted by this change, astronauts on the International Space Station are at risk. This is why this fluctuation requires constant monitoring.