The European Space Agency’s (ESA) Swarm mission is dedicated to studying Earth’s magnetic field. Launched in 2013, the mission uses three satellites to map the magnetic field with unprecedented precision and resolution. This data helps scientists understand the complex processes within Earth’s core and their impact on the planet’s magnetic field.
One of the fascinating phenomena that Swarm is helping us understand is geomagnetic excursions – brief periods where the Earth’s magnetic field reverses its polarity. The Laschamp event, which occurred approximately 42,000 years ago, is a prime example of such an excursion.
The Laschamp Event: A Magnetic Flip-Flop
During the Laschamp event, Earth’s magnetic field dramatically weakened, reaching just 5% of its current strength before flipping to a reversed state for about 440 years. This temporary reversal had significant impacts on our planet:
- Increased Cosmic Radiation: The weakened magnetic field allowed more cosmic rays to penetrate Earth’s atmosphere, leading to a greater production of cosmogenic isotopes like beryllium-10 and carbon-14.
- Atmospheric Changes: The increased radiation affected atmospheric ozone levels and altered atmospheric circulation patterns.
There have been claims that the Laschamp event contributed to the extinction of some megafauna species, the Neanderthals, and even the emergence of cave art. However, scientific evidence for these claims is currently weak and debated.
Recreating the Sound of a Magnetic Flip
Scientists at the Technical University of Denmark and the German Research Centre for Geosciences used data from ESA’s Swarm mission, along with other sources, to create a sounded visualisation of the Laschamp event. They mapped the movement of Earth’s magnetic field lines during the event and created a stereo sound version which is what you can hear in the video. The soundscape was made using recordings of natural noises like wood creaking and rocks falling, blending them into familiar and strange, almost alien-like, sounds.