Giant Magnetic Waves Have Been Discovered Oscillating Around Earth's Core

Earth is not a quiet place. Beneath our surface activities, the planet is active, from plate tectonics to convection currents that circulate through the hot magmatic fluids far underneath the crust.

Scientists studying satellite data of Earth have found a new type of magnetic wave that sweeps around the surface of our planet every seven years.

This discovery could offer insight into how Earth's magnetic field is generated, and provide clues of our planet's thermal history and evolution, that is, the gradual cooling of the planetary interior.

The waves are at the core-mantle boundary. The University of Grenoble Alpes.

geophysicists have long speculated over the existence of such waves, but they were thought to take place over much longer time scales than our research has shown.

Measurement of the magnetic field from instruments 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.

The ground-based data had thrown up what a computer model of the geodynamo explained.

Scientists are interested in the subject of the Earth's magnetic field. The invisible structure forms a protective bubble around our planet, keeping harmful radiation out and the atmosphere in, thus allowing life to thrive.

The magnetic field is not static. It varies in strength, size, and shape, and has features we don't understand.

The magnetic field that comes from our planet is important. It is generated by a rotating, convecting, and electrically conducting fluid that converts energy into magnetic energy, spinning a magnetic field out into space around the planet.

The molten iron is inside the outer core.

The European Space Agency launched a trio of identical probes to study the activity inside Earth, with a specific eye on the magnetic and dynamic activity coming out of the core. Gillet and his team discovered the new waves from this data.

They studied the data from other ground and space-based observatories and found a pattern.

The strongest of these waves are at the equator.

They sweep around the boundary between the core and the mantle with an amplitude of around 3 kilometers per year, and then move west at a rate of up to 1,500 kilometers per year.

The existence of these waves suggests that other waves might have different periods of activity.

Gillet says that magnetic waves are likely to be triggered by disturbances deep within the Earth's fluid core.

Our research suggests that other waves are likely to exist, but their discovery is dependent on more research.

Because waves carry information about the medium through which they travel, new discovery could be used to probe the interior of our planet in new ways.

The research was published in PNAS.