Mapping out our magnetic field, and understanding how it interacts with solar particles, is science that basically helps keep our civilization alive. After all, we’re pretty sure life owes a debt of gratitude to that magnetic field, which protects us from cosmic radiation and the solar winds. And that field is generated deep inside Earth, where the outer core of our planet is made of liquid iron, spinning and swirling, creating a dynamo.

Now, research published in ​​the Proceedings of the National Academy of Sciences presents evidence of a newly discovered type of magnetic wave that runs along the outer edge of the core up against the mantle. The wave oscillates over a seven-year time frame and moves westward at 1,500 kilometers per year. Lead author Nicolas Gillet explains: Geophysicists have long theorized 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.”

That global coverage came from the European Space Agency’s Swarm satellites, a trio of identical satellites launched in 2013 for just this type of observation. The data collected was combined with measurements from two other European missions – Germany’s Champ and the Netherlands’ Ørsted – to create a computer model of Earth’s dynamo.

The team suspects that there are longer period waves to be found, but obviously, more observing time is necessary.

More Information

ESA press release

“Satellite magnetic data reveal interannual waves in Earth’s core,” Nicolas Gillet et al., 2022 March 21, PNAS