The Sound of Our Magnetic Field

View of the Earth as seen by the Apollo 17 crew traveling toward the moon by NASA on Unsplash

I have never considered the fact that the Earth’s magnetic field could produce any sound. However, the Technical University of Denmark has taken the magnetic field signals and converted them into a sound that was played in Copenhagen. This art installation played the borderline creepy sound three times a day for a week straight. The rumbling intrigued me since it reminds me more of horror media, but the sound is proof of the magnetic field’s protection of Earth.

European Space Agency · The scary sound of Earth’s magnetic field

What is Earth’s magnetic field?

The magnetic field around the world is also known as the geomagnetic field. It shields the earth from charged particles from the sun and cosmic particle radiation. Without it, life on earth would not really be possible. It forms a comet-shaped field around the planet. As you may know from using a compass, the earth has magnetic poles. When you use a compass, it points to the geographic North Pole, but it actually points to the south magnetic pole of the earth. This also means that the north magnetic pole of the earth is on the other side, AKA near the geographic South Pole. Apparently, these magnetic poles are not entirely fixed to one place, but they move around a little. Moreover, they have also flipped, but this happens maybe every 200,000 years.

Between these two magnetic poles, the magnetic field circulates. It is generated by something that is called the geodynamo process. This process has a few prerequisites:

  • The planet needs to rotate;
  • The interior of the planet must contain a fluid medium;
    • This fluid medium needs to be able to conduct electricity;
  • The planet must have an internal energy supply that creates convection in the liquid.

The geodynamo process takes place in the outer core of Earth. The magnetic field is affected by the speed of the rotation, the conductivity of the fluid, and heat. In the outer core is molten iron, which is the electrical conductor that creates the electrical currents that go through the magnetic field.

The noise

The European Space Agency (ESA) had a Swarm satellite mission that investigated the magnetic field of planet Earth. The satellite mission measured magnetic signals, which were converted into sound by scientists at the Technical University of Denmark. The team of scientists used a combination of the Swarm satellites and other sources to create an audio of the core field. Like Klaus Nielsen from the TU of Denmark said, “The project has certainly been a rewarding exercise in bringing art and science together” (cited from ESA’s article explaining the project).

Now, you might be wondering, how exactly did it bring science and art together? Well, the sound that definitely sounds like something of an analog horror series was played at the Solbjerg Square in Copenhagen. There were 32 loudspeakers in the ground that each represented a different location on Earth. The noise was played from 24-30 October three times a day. This demonstration of the magnetic field was meant to show how Earth’s magnetic field has changed over the last 100 000 years. Moreover, some of the rumbling lets us hear what a representation of a  geomagnetic storm sounds like.

European Space Agency · Bringing Earth’s magnetic rumble to Copenhagen

Personally, I think the project is very interesting. It is a surprise to me that there are ways to convert magnetic signals into audio format. On top of that, I do agree that the demonstration as an art piece is a very good representation of science and art together. Even though the audio sounds pretty scary, the fact that they represent the protection of life on Earth is something that makes it very special. It is not a sound I would associate with safety. However, the noise does serve as a reminder of something being out there that ensures we can continue our daily routines and of our small existence in space, with all of that noise going on without us knowing about it.