Earth’s magnetic field is gradually weakening which is resulting in technical disturbances in some satellites orbiting the Earth. According to the reports, a rapid shrink has been observed in the South Atlantic Anomaly. The ‘South Atlantic Anomaly’ (SAA) is referred to the behaviour of Earth’s Geo-Magnetic field in an area between Africa and South America.
Over the last 200 years, the magnetic field has lost around 9% of its strength on a global average, said the European Space Agency (ESA). A large and rapid shrink has been observed in SAA region over the past 50 years just as the area itself has grown and moved westward.
The weakening of the magnetic field is also causing technical difficulties for the satellites and spacecrafts orbiting the planet.
The study, conducted between 1970 and 2020, said that the magnetic field weakened considerably in a large region stretching from Africa to South America, known as the ‘South Atlantic Anomaly’. This area has grown and moved westward at a rate of around 20km per year.
The reason for the reducing magnetic field is not entirely known and researchers/scientists are using Swarm constellation of ESA and international consortium called “Swarm Data, Innovation and Science Cluster (DISC)” to improve their understating of this area and the anomaly. Swarm is a ESA’s mission to study the Earth’s magnetic field.
An ESA article on the matter, said –
Earth’s magnetic field is vital to life on our planet. It is a complex and dynamic force that protects us from cosmic radiation and charged particles from the Sun. 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.
In the Video below, which is made available by ESA, shows the dots on the map that indicate individual events when Swarm instruments registered the impact of radiation from April 2014 to August 2019. The background is the magnetic field strength at the satellite altitude of 450 km.
“It has been speculated whether the current weakening of the field is a sign that Earth is heading for an eminent pole reversal – in which the north and south magnetic poles switch places. Such events have occurred many times throughout the planet’s history and even though we are long overdue by the average rate at which these reversals take place (roughly every 250 000 years), the intensity dip in the South Atlantic occurring now is well within what is considered normal levels of fluctuations,” said ESA article.
Currently, there is no reason to panic, at least at surface level. However, satellites and other spacecraft flying through the SAA area are more likely to experience technical malfunctions as the magnetic field is weaker in this region, so charged particles can penetrate the altitudes of low-Earth orbit satellites, said the ESA.
Meanwhile, magnetic field observations from Swarm satellites are providing new insights into the scarcely understood processes of Earth’s interior. The Swarm satellites can identify and measure the the various magnetic signals that combine to make up the Earth’s magnetic field.In the last five years, a second centre of minimum intensity has developed towards southwest of Africa. Researchers believe that this could mean that the anomaly can split into two separate cells.