The Earth’s magnetic field isn’t only useful for setting compasses. Generated deep inside our planet by flows of molten metal, the field also acts as a protective cloak against damaging solar radiation. But 41,000 years ago, that shield effectively weakened for hundreds of years.
This event, called a geomagnetic excursion, likely had huge consequences for our planet.
Even if the global destruction of a massive, invisible energy field seems too big to comprehend, you can now listen to the event thanks to researchers at the European Space Agency (ESA), who recreated the sound of the magnetic field failing in 2024.
The Sound of a Magnetic Field Failing
To generate the sound, researchers used data from the ESA’s Swarm mission, which consists of three identical satellites that monitor the magnetic field and how it changes. ESA researchers mapped the field changes that occurred throughout the excursion.
They incorporated the data into a soundscape built with natural noises, like creaking timber and scraping rockfalls. The ESA previously assembled the sound of our magnetic field over the last 100,000 years, and blasted it at unsuspecting pedestrians in a public square in Copenhagen, Denmark, in 2022.
The ESA’s aural version of a failing magnetic field sounds like massive, ancient gears crunching in some alien machine. That is to say, not very pleasant.
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What is the Laschamp Event?
Excursions are events where the planet’s magnetic field weakens and wanders, potentially reducing its strength by more than 95 percent and relocating geomagnetic poles around the globe.
During this period, the weakened field effectively reverses. The excursion 41,000 years ago was the first excursion to be discovered. It’s called the Laschamp event because scientists first noted its lasting effects in lava flows in central France.
The Laschamp event is thought to have taken a heavy toll on our planet. Because the protective magnetic shield weakened so much, Earth would have been much more vulnerable to damaging solar rays. Deposits analyzed from deep within ice cores and sediment from the bottom of the ocean suggest that chemical signatures linked to cosmic rays doubled over the period of the Laschamp event. Researchers have linked the loss of the magnetic shield to declines in ancient animal populations.
How the Laschamp Event May Have Changed the Planet
A 2021 study in Science about giant kauri trees in New Zealand, preserved deep in peat bogs since the Laschamp event, suggested the field switch brought arid conditions to nearby Australia. This weather shift may have been linked to the extinction of ancient megafauna — think massive wombats and kangaroos — around the same time. On the other side of the globe, vast ice sheets rapidly grew across North America, and the neanderthals went extinct in Europe.
In short, another Laschamp event is the last thing we need. Luckily, researchers are closely monitoring our magnetic field to anticipate any changes.
“There is no evidence the field could drastically weaken soon,” Sanja Panovska, a scientist at GFZ Potsdam and co-author on the new study, told Discover.
Even if an excursion began tomorrow, it would be some time before we felt its effect.
“These changes happen on long timescales, in the order of [thousands of years],” said Panovska.
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Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
- This article references information from the ESA: The scary sound of Earth’s magnetic field
- This article references information from the ESA: Sound of Earth’s magnetic flip 41 000 years ago
- This article references information from a study published in Science: A global environmental crisis 42,000 years ago
