Earth's magnetic field creates worry among scientists

Scientists are using data from ESA’s Swarm constellation to improve our understanding of this area known as the ‘South Atlantic Anomaly.'

A part of the earth’s magnetic field is weakening, and no one really knows why. Satellite data pondered over by scientists has revealed a rather worrying development that the magnetic field is weakening between Africa and South America. Scientists say the area known as South Atlantic Anomaly has significantly widened over the past few years. The European Space Agency's (ESA) Swarm constellation of satellites have noticed a reduction in the strength from around 24 000 nanoteslas to 22 000 nanoteslas. The area of the anomaly has also grown and moved westward at around 20 km per year. What is worrying scientists is that a second area of minimum intensity has emerged southwest of Africa, which is an indication that the South Atlantic Anomaly could split up into two separate cells.

The earth's magnetic field is generated by movements within the planet's molten iron core. This emerges out and goes as far as provide a shield for earth in space and protects the living beings from the harmful radiation of the sun. A stronger magnetic field blocks out more radiation from reaching the earth’s surface. “The magnetic field is largely generated by an ocean of superheated, swirling liquid iron that makes up the outer core around 3000 km beneath our feet. Acting as a spinning conductor in a bicycle dynamo, it creates electrical currents, which in turn, generate our continuously changing electromagnetic field,” say the scientists.

“The new, eastern minimum of the South Atlantic Anomaly has appeared over the last decade and in recent years is developing vigorously. We are very lucky to have the Swarm satellites in orbit to investigate the development of the South Atlantic Anomaly. The challenge now is to understand the processes in Earth’s core driving these changes,” says Jürgen Matzka, from the German Research Centre for Geosciences.

The ESA believes that one of the reasons for this weakening magnetic field in the region could indicate an imminent reversal, where the North Pole and the South Pole switch. Scientists say this has happened before as well and happens roughly every 250 000 years.

The reversal could mean a change in how the magnetic field protects the earth from harmful cosmic radiation as well as space winds. Satellites could be rendered in-operational, which could have significant disruptions for communication systems around the world, including telecom networks and mobile phones. Scientists say spacecraft flying through the area are more likely to experience technical malfunctions.

This is set to rumble on, quite literally, because magnetic field reversals don’t usually happen in a day. But if things are indeed headed towards the North Pole and the South Pole swapping places, you probably wouldn’t want to be around to witness it.