ESA's Orbiting Satellite Finds Giant Magnetic Wave in Earth's Core
Earth’s magnetic field protects us from aggressive cosmic radiation. Without the magnetic field, life on our planet as we know it could not exist.
The European Space Agency's (ESA) Swarm satellite mission
has detected a completely new type of magnetic wave.
The results of the mission were published
in the journal Proceedings of the National Academy of Sciences.
Experts hope that the findings will help them to learn more about Earth’s magnetic field, without which life on our planet would not have existed.
Earth's magnetic field protects us from harmful cosmic radiation. It has been decades since scientists first started examining the field's behaviour. However, until recently, they could not say they completely understood fluctuations in the field's strength as measured by satellites.
The newly discovered magnetic wave circulates at a depth of more than 3,000 kilometres below Earth's surface, where the planet's core meets its mantle. It travels westward 1,500 km a year, meaning that it circumnavigates the globe every seven years.
"Geophysicists have long theorised over the existence of such waves, but they were thought to take place over much longer time scales than our research has shown...Measurements of the magnetic field from instruments based on the surface of Earth suggested that there was some kind of wave action, but we needed the global coverage offered by measurements from space to reveal what is actually going on", said Nicolas Gillet, a geophysicist at the University of Grenoble Alpes in France and the lead author of the new paper.
After combining data from three Swarm satellites with measurements made by the previously used German satellite CHAMP and the Danish Orsted, the researchers used a computer model simulating the process of the generation of Earth's magnetic field to run the measured fluctuations through it. As a result of this, they found out that this kind of slow-moving magnetic wave could be the cause of the magnetic field's fluctuations.
According to Gillet, learning what processes in the Earth's depths provoke such magnetic waves requires further research.