While volcanic eruptions and earthquakes serve as instant reminders that the Earth’s interior is not peaceful, other elusive dynamic processes occur deep within our feet. Using information from the European Space Agency’s Swarm transmissions, scientists have discovered an entirely new type of magnetic wave that sweeps through the outer part of Earth’s outer core every seven years. This remarkable discovery, revealed today at the European Space Agency’s Living Planet Symposium, opens a new window on a world we can never see.
Earth’s magnetic field It’s like a huge bubble that protects us from cosmic radiation and charged particles carried by strong winds that escape the sun’s gravity and stream through the solar system. Without our magnetic field, life as we know it would not exist.
constellation swarm. Acknowledgments: ESA / ATG Medialab
Understanding exactly how and where our magnetic field originates, why it constantly fluctuates, how it interacts with the solar wind, and why it is already weakening at present is beneficial not only to science but also to society. for example, Solar storms can destroy communication networks And navigation systems and satellites, so while we can’t do anything about changes in the magnetic field, understanding this invisible force will help you prepare.
Much of this field is created by an ocean of superheated swirling liquid iron that forms the Earth’s outer core 3,000 kilometers below our feet. It acts as a rotating conductor in a bicycle dynamo, generating an electric current and a constantly changing electromagnetic field.
The European Space Agency’s Swarm mission, made up of three identical satellites, measures these magnetic signals from Earth’s core, as well as other signals from the crust, oceans, ionosphere and magnetosphere.
Since the launch of three Swarm satellites in 2013, scientists have been analyzing their data to gain new insights into the many natural processes on Earth. space climate I Physics and dynamics The stormy heart of the earth.
Using information from the European Space Agency’s Swarm transmissions, scientists have discovered an entirely new type of magnetic wave that sweeps through the outer part of Earth’s outer core every seven years. This remarkable discovery opens a new window into a world we can never see. This mysterious wave oscillates every seven years and travels westward at up to 1,500 kilometers (900 miles) per year. Acknowledgments: European Space Agency / Planet Insights
Measure our magnetic field from space This is the only real way to study the depths of the Earth’s core. Seismology and mineral physics shed light on the physical properties of the core, but do not shed light on the dynamo-generating motion of the liquid outer core.
Now, however, using data from the Swarm mission, scientists have discovered a hidden secret.
Article published in the magazine Proceedings of the National Academy of Sciences, describes how a group of scientists discovered a new type of magnetic wave that sweeps across the “surface” of Earth’s outer core – where the core meets the mantle. This mysterious wave oscillates every seven years and travels westward at up to 1,500 kilometers (900 miles) per year.
“Geophysics has long been theoretically interested in the existence of such waves, but they are thought to occur over a much longer period of time than our research has shown,” said Nicholas Gillet, of Grenoble Alps University and lead author of the study.
Magnetic field measurements from ground-based instruments suggested that there was some kind of wave motion, but we needed the global coverage provided by measurements from space to reveal what was really going on.
“We combined satellite measurements from Swarm and the previous German missions Champ and Danish Ørsted with a geodynamic computer model to explain the cause of the terrestrial data—and this led to the discovery.”
Because of the Earth’s rotation, these waves line up in columns along the axis of rotation. The motion and magnetic field changes associated with these waves are strongest in the equatorial region of the nucleus.
While research shows the presence of magnetic Coriolis waves near a seven-year period, the question whether such waves oscillate in different periods remains.
Dr Gillette added: “The magnetic waves are likely caused by disturbances in Earth’s liquid core which are likely related to buoyancy plumes. Each wave is determined by its duration and a typical length scale, and the duration depends on the characteristics of the forces acting. Coriolis magnetic waves, indicate Period to the strength of the magnetic field inside the heart.
“Our research suggests that there may be other waves like this, possibly in the longer term – but finding them depends on further research.”
Elias Daras, a scientist on the European Space Agency’s Swarm mission, noted that “this current research will certainly improve the scientific model of the magnetic field in the Earth’s outer core. It could provide new insights into the electrical conductivity of the lower mantle, as well as the Earth’s thermal history.”
Reference: “Magnetic satellite data reveal mid-year waves in Earth’s core” – Nicholas Gillett, Felix Gerek, Dominic Gault, Tobias Schweiger, Julian Ober, and Matthew Estas, 21 Mar. 2022 Available here Proceedings of the National Academy of Sciences.
DOI: 10.1073/pnas.2115258119
Research supported by the ESA’s Science for Society program was presented at this week’s ESA Planetary Biology Symposium in Bonn, Germany. Participants will hear about the latest scientific discoveries about our planet and how observing Earth from space supports environmental research and action to combat the climate crisis. They also hear about new space technologies and new opportunities in the rapidly changing Earth observation sector. Selected sections are broadcast, see ESA Web TV channels.
