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ESA’s SWARM investigates weakening of Earth’s magnetic field, possible split up of South Atlantic Anomaly


Over the past 200 years, Earth's magnetic field has lost around 9% of its strength. Meanwhile, a large region of reduced magnetic intensity has developed between Africa and South America — known as South Atlantic Anomaly. Over the past 5 years, however, a second center of minimum intensity has emerged southwest of Africa, suggesting that the South Atlantic Anomaly could split up into two separate cells.

Earth's magnetic field is vital to life on our planet– it is a complex and dynamic force that protects living beings from cosmic radiation and charged particles from the Sun.

The current prevailing understanding is that it's largely generated by a sea of superheated, swirling liquid iron that makes up Earth’s outer core around 3 000 km (1 864 miles) below the surface. It acts as a spinning conductor, producing electrical currents that generate the continuously changing electromagnetic field.

It's known that the field varies in strength and direction. For instance, recent studies have shown that the north magnetic pole's position is rapidly migrating toward Siberia.

Image credit: World Data Center for Geomagnetism/Kyoto University

Image credit: World Data Center for Geomagnetism/Kyoto University

For the past 200 years, the magnetic field has lost about 9 percent of its strength on a worldwide average.

Meanwhile, a large region of reduced magnetic intensity has developed between Africa and South America — known as the South Atlantic Anomaly.

YouTube video

The South Atlantic Anomaly refers to an area where our protective shield is weak. This animation shows the magnetic field strength at Earth’s surface from 2014-2020 based on data collected by the Swarm satellite constellation. Credit: ESA

The minimum field strength in this area has pummeled from 24 000 nanoteslas to 22 000 from 1970 to 2020. At the same time, the area of the anomaly has expanded and advanced westward at a pace of around 20 km (12 miles) per year.

In addition, for the past five years, a second center of minimum intensify has appeared southwest of Africa, indicating that the South Atlantic Anomaly could rupture into two separate cells.

The magnetic field is commonly pictured as a powerful dipolar bar magnet at the planet's core, tilted at about 11° to the axis of rotation. However, the growth of the anomaly signifies that the process involved in generating the field is more complex as simple dipolar models were not capable of accounting for the latest development of the second minimum.

YouTube video

The South Atlantic Anomaly refers to an area where our protective shield is weak. White dots on the map 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 (280 miles). Credit: ESA

Scientists from the Swarm Data, Innovation, and Science Cluster (DISC) used information from ESA's Swarm satellite constellation to study the anomaly and have a better understanding of it. Swarm satellites are built to determine and accurately measure the different magnetic signals comprising the Earth's magnetic field.

"The new, eastern minimum of the South Atlantic Anomaly has appeared over the last decade and in recent years is developing vigorously," said Jurgen Matzka from the German Research Center for Geosciences.

"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."


Image credit: ESA/ATG Medialab

Scientists have been speculating whether the present weakening of the field is an indication that the planet is heading for an imminent pole reversal, in which the north and south magnetic poles reverse places.

Such events have happened many times throughout the Earth's history, and we are long overdue by the average rate — roughly every 250 000 years at which the switch occurs.

While the mysterious origin of South Atlantic Anomaly is yet to be identified, ESA said that at the surface level it does not present a cause for alarm. However, satellites and other spacecraft flying through the 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. In addition, SWARM scientists think the intensity dip in the South Atlantic occurring now is well within what is considered normal levels of fluctuations.

Featured image credit: ESA/ATG Medialab

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  1. Notre Galaxie est une galaxie de type “spirale”. Elle est dominée par un disque dont les étoiles tournent autour du centre qui est constitué d’un bulbe et d’une barre. Entre 70% à 80% des étoiles sont dans le disque qui a un diamètre de 90 000 années-lumière pour une épaisseur de seulement 2500 années-lumière. Le disque est constitué de plusieurs bras spiraux dans lesquels se concentre la majorité des étoiles. On pense que les bras se forment naturellement par des instabilités gravitationnelles induites lors de la rotation du disque. Les deux bras spiraux qui dominent la Galaxie sont ceux de Scutum-Centaurus et de Perseus, le Soleil se trouvant dans un bras secondaire, appelé bras d’Orion. Mais. Mais le mouvement de notre galaxie n est pas uniforme car les poids des bras sont différents et cela infuera sur le mouvement des brats qui devra inversé son magnétique pour contrer le poids. Je pense que c’est un cycle qui se répète pour que la galaxie reste en équilibre. Mais si mon theory d équilibre galaxial est juste en devra trouver des indices dans les planètes de notre système solaire. Merci. Autrement une chose est certaine pour contrer le poids en inverse le champ magnétique. C’est le principe des nouveaux avion ufo.

  2. Now I have no knowledge behind any of my theories but could one argue this Is happening due to the amount of satellites we have in orbit or could it be linked with planet 9. Once again I do not research or study any field associated with this so apologies for a stupid/idiotic theory

  3. And the dip of the magnetic south pole drops further into the Antarctic (actual -3.240m) towards the south indian ridge, while the dip of the magnetic north pole soon goes from -4.000m to -850m at the lomonosov ridge. The result will be a decrease in the annual average temperature in RMI (Belgium) and BOM (Australia) just like what happened with the ALPHA ridge

  4. IT IS ABSOLUTELY IMPOSSIBLE TO PROVIDE TRUE SCIENTIFIC EXPLANATIONS BASED ON CURRENT GEOPHYSICS………”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.” ………………..The logical and the most important questions that should be asked, are what causes these changes at the core and why these changes take place on a cyclic period of thousands of years? HOWEVER, KEEP IN MIND, THAT THE CHANGES WHICH TAKE PLACE IN THE EARTH’S CORE ARE ALWAYS THE REASON FOR THE REVERSAL OF THE FIELD. YES, IT IS A CHALLENGE FOR YOU-SCIENTISTS FROM THE SWARM DATA-. BUT, I ASSURE YOU THAT YOU CANNOT FIND THE ANSWER WITHIN THE DOMAIN OF CURRENT GEOPHYSICS.

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