Close to 41,000 years ago, Earth underwent a magnetic field reversal where, for a short period, the planet’s natural magnetic protective shield diminished to just 5% of its current strength.
During this sudden and extreme magnetic field reversal event, the temporary weakness of Earth’s magnetic barrier allowed a significant influx of cosmic rays to penetrate Earth’s atmosphere. Now, for the first time, a team of scientists have produced a sound visualization of this mysterious ancient occurrence.
The Laschamp Event
Between 42,200 and 41,500 years ago, Earth’s magnetic field underwent a sudden and dramatic decrease in the intensity, along with a shift in pole orientation by about 45 degrees.
Known as the Laschamp event, this was a type of geomagnetic excursion—an anomaly in Earth’s magnetic field and the first of its kind to be identified. During geomagnetic excursions, the weakened magnetic field provides less protection from cosmic radiation, which researchers believe may have caused significant effects on Earth including extreme changes to Earth’s biosphere.
Scientists are able to identify periods of heightened cosmic ray bombardment by examining radionuclides found in places that include marine sediment cores and ancient ice deposits. The isotopes produced by the interaction between Earth’s atmosphere and cosmic radiation serve as markers for times when cosmic rays were able to penetrate more easily and reach the planet.
Now, scientists at the Technical University of Denmark and the German Research Centre for Geosciences have used Laschamp event data, including new information obtained by the ESA’s Swarm mission, to create the first visualization of the mysterious event with sound.
Giving a Voice to an Ancient Mystery
The movement of Earth’s magnetic field lines as they would have occurred during the event 41,000 years ago were mapped by the international team of scientists, allowing them to create a genuinely eerie stereo sounded visualization, which you can hear below:
The audio featured in the research team’s soundscape was created by combining noises captured from nature that include tumbling stones, creaking wood, and other sounds equally worthy of appearances in horror cinema. These sounds were blended into what the European Space Agency (ESA) recently called a cacophony of “familiar and strange, almost alien-like, sounds,” likening the audio mashup to the creation of a musical composition.
Although the completed soundscape is closer to art than being an actual representation of how the Laschamp event may have sounded, it nonetheless offers a stimulating addition to the accompanying visualization.
An early version of the sonification was played in a live setting in Copenhagen, where a 32-speaker system blasted the unsettling audio throughout a public square. During this live event, each speaker in the sound system was used to represent different changes that occurred in Earth’s magnetic field at various locations around the world over a 100,000 year period in our planet’s history.
Understanding Earth’s Magnetic Field
Currently, scientists are using the new data obtained from the ESA’s Swarm constellation along with existing data to help reveal more about the processes that give rise to the generation of Earth’s Magnetic Field.
Obtaining data that emanates from not only the core of the planet, but also data from regions that include the crust, oceans, the planet’s ionosphere, and directly from the magnetosphere, the Swarm constellation helps provide potentially significant data that could help scientists to better understand the dynamics of geomagnetic reversal events.
Additional information about the ESA’s magnetic field mission and its current efforts usinf the Swarm constellation to obtain data about our planet and occurrences like the Laschamp event has been made available at the ESA’s website.
Micah Hanks is the Editor-in-Chief and Co-Founder of The Debrief. He can be reached by email at micah@thedebrief.org. Follow his work at micahhanks.com and on X: @MicahHanks.