Scientists have detected an entirely new, mysterious type of magnetic wave that travels through Earth’s outer core every seven years, distorting the strength of our planet’s magnetic field in the process.
According to what the researchers wrote in the article published in the journal Proceedings of the National Academy of Sciences, waves called “Magneto-Coriolis” waves because they move along the axis of the Earth’s rotation occur in the East in long columns that can travel up to 1,500 kilometers per year. moves to the West. Using a fleet of European Space Agency (ESA) satellites, the team was able to detect these mysterious waves in the outermost layer of Earth’s liquid outer core, exactly where this layer meets the rocky mantle, about 2,900 kilometers below the planet’s surface.
The presence of these waves may help explain the mysterious fluctuations in the planet’s magnetic field caused by the movement of liquid iron in the planet’s outer core, the researchers say. Satellite measurements of the magnetic field taken over the past 20 years have shown that the strength of the field drops every seven years, which seems to be in line with the oscillations of the newly discovered waves.
Researcher at the University of Grenoble Alpes in France, Nicolas Gillet, lead author of the study, said in a statement: “Geophysicists have long theorized about the existence of such waves, but they were thought to occur on much longer timescales.” , indicating that other such waves could possibly exist for longer periods – but their discovery is based on further research.”
Earth’s outer core is a sphere of molten iron agitated in perpetual motion. The flow of this swirling, electrically conductive fluid is thought to be the source of Earth’s magnetic shield that wraps around the planet and extends hundreds of thousands of miles into space, protecting Earth from harmful radiation.
The magnetic field of the planet is constantly changing on both short-term and long-term time scales. In the long run, the magnetic field has been gradually weakening over hundreds of years. Recent measurements taken by ground- and satellite-based instruments show regular changes in the strength and shape of the magnetic field that occur every few years.
Scientists have long thought that these short-term changes in field strength are influenced by activity in the planet’s outer core. This new study may provide the long sought-after evidence.
Study authors analyzed more than 20 years of magnetic field data collected by ESA’s Swarm satellite mission between 1999 and 2021. Swarm is a fleet of three identical satellites deployed to measure magnetic signals from Earth’s core, crust, oceans, and atmosphere. The team combined this satellite data with previous magnetic field measurements taken by ground-based sensors and then used a computer model to simulate the geodynamo, or convective fluid flow in Earth’s outer core.
Thanks to these combined measurements, the team detected the presence of Magneto-Coriolis waves in the planet’s core for the first time.
26867
