Despite being essential to life on Earth, the magnetic field is not something we can see or hear. However, scientists at the Technical University of Denmark have converted magnetic signals measured by ESA’s Swarm satellite mission into sound, which is quite frightening.
The Earth’s magnetic field is a complex and dynamic bubble that protects us from cosmic radiation and charged particles carried by powerful solar winds. When these particles collide with atoms and molecules in the upper atmosphere, primarily oxygen and nitrogen, some of the energy in the collisions is transformed into the green-blue light characteristic of the aurora borealis, which can sometimes be seen from space.
While the aurora borealis shows charged particles from the Sun interacting with Earth’s magnetic field, hearing the magnetic field generated by Earth or its interaction with solar winds is a different story.
Our magnetic field is largely generated by an ocean of superheated, swirling liquid iron that forms the outer core 3000 kilometres beneath our feet. It generates electrical currents by spinning like a conductor in a bicycle dynamo, which in turn causes our constantly changing electromagnetic field.
ESA’s trio of Swarm satellites, launched in 2013, are being used to understand exactly how our magnetic field is generated by precisely measuring magnetic signals that originate not only from Earth’s core but also from the mantle, crust, and oceans, as well as the ionosphere and magnetosphere.
“The team used data from ESA’s Swarm satellites and other sources and used these magnetic signals to manipulate and control a sonic representation of the core field. The project has certainly been a rewarding exercise in bringing art and science together.” Explained Klaus Nielsen, a musician and project supporter from the Technical University of Denmark.
It may sound like something out of a nightmare, but the audio recording below depicts the magnetic field generated by Earth’s core and its interaction with a solar storm.
“We gained access to a very interesting sound system consisting of over 30 loudspeakers dug into the ground at the Solbjerg Square in Copenhagen.
“We have set it up so that each speaker represents a different location on Earth and demonstrates how our magnetic field has fluctuated over the last 100 000 years.
“Throughout this week, visitors will be able to hear the amazing rumble of our magnetic field – so if you are in Copenhagen, come along and check out this unique opportunity.
“The rumbling of Earth’s magnetic field is accompanied by a representation of a geomagnetic storm that resulted from a solar flare on 3 November 2011, and indeed it sounds pretty scary.”
The purpose is not to intimidate people but to remind them that the magnetic field exists and that life on Earth depends on it, even though its rumble can be unsettling.