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.
Hellbound and Down 