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Despite being necessary for life on Earth, the magnetic field is not something we can actually see by itself, or ever hear. But, incredibly, scientists at the Technical University of Denmark have taken the magnetic signals measured by ESA’s Swarm satellite mission and turned them into sound – and for something that protects us, the result is pretty terrifying.
The Earth’s magnetic field is a complex and dynamic bubble that protects us from cosmic radiation and charged particles carried by strong winds coming from the Sun. When these particles collide with atoms and molecules – mostly oxygen and nitrogen – in the upper atmosphere, some of the energy in the collisions is transformed into the green-blue light typical of the aurora borealis, which can sometimes be seen from high northern latitudes.
While the aurora borealis offers a visual representation of charged particles from the Sun interacting with Earth’s magnetic field, actually being able to hear the Earth’s generated magnetic field or its interaction with the solar wind is another matter.
Our magnetic field is mainly generated by the ocean of superheated, swirling liquid iron that makes up the outer core about 3,000 km below our feet. Acting like a spinning conductor in a bicycle dynamo, it creates electrical currents, which in turn create our ever-changing electromagnetic field.
Launched in 2013, ESA’s trio of Swarm satellites are used to understand exactly how our magnetic field is generated by precisely measuring magnetic signals originating not only from the Earth’s core, but also from the mantle, crust and oceans, as well as from the ionosphere and magnetosphere. The swarm also leads to new insights into space weather.
Musician and project supporter Klaus Nielsen, from the Technical University of Denmark, explains: “The team used data from ESA’s Swarm satellites, as well as other sources, and used these magnetic signals to manipulate and control the sonic representation of the core field. The project was certainly a rewarding exercise in merging art and science.
It may sound like a nightmare, but, incredibly, this audio recording represents the magnetic field generated by the Earth’s core and a solar storm.
“We got access to a very interesting sound system consisting of over 30 speakers buried in the ground at Solbjerg Square in Copenhagen.
“We set it up so that each speaker represents a different location on Earth and shows how our magnetic field has fluctuated over the last 100,000 years.”
“During this week, visitors will be able to hear the incredible rumble of our magnetic field – so if you’re in Copenhagen come and see this unique opportunity.”
“The rumble of Earth’s magnetic field is accompanied by a display of the geomagnetic storm that resulted from the solar flare on November 3, 2011, and it sounds pretty scary indeed.”
The intention, of course, is not to scare people – it’s an unusual way of reminding us that the magnetic field exists and although its rumble is a little disturbing, the existence of life on Earth depends on it.
Loudspeakers in Solbjerg Square in Copenhagen, Denmark will broadcast the rumble of the Earth’s magnetic field on the 24th-30th. October around 08:00, 13:00 and 19:00.