Earth’s magnetic poles are crucial in creating and maintaining its magnetic field, which protects the planet from harmful cosmic radiation and helps living things navigate like a compass. However, this was not always the case.
The reversal of the north and south poles, also known as the geomagnetic pole shift, has a significant impact on the Earth. During such pole shifts, the Earth’s magnetic field could weaken, and this would completely turn the ecosystem and human life upside down. Scientists are still investigating these processes, but it is difficult to make adequate predictions.
This happened to the Earth 41 thousand years ago
The Laschamps event was a time in our planet’s history when the geomagnetic poles were reversed. This pole shift occurred in the middle of the Ice Age and lasted for about a thousand years. The Laschamps event had a significant impact on the living world and the ecosystem, the weakening of the Earth’s magnetic field facilitated the penetration of harmful cosmic rays into the Earth’s atmosphere in greater quantities.
In connection with the reversal of the magnetic poles, a research group is now trying to understand the Laschamps event by studying ice and marine sediment cores. Scientists from Germany’s GFZ Potsdam examined cosmogenic radionuclides trapped in sediments, which entered the Earth’s atmosphere with increased cosmic radiation. And these cosmogenic materials interacted with atmospheric atoms, thus creating these isotopes.
Connection between field strength and cosmogens
The aim of the study is for the researchers to reveal the relationship between the paleomagnetic field strength and cosmogenic nuclides, which most likely came to Earth in such quantities during the Laschamps overturn. In connection with the geomagnetic pole shift, the intensity of the Earth’s paleomagnetic field weakened, and this caused the interaction of cosmic isotopes with atoms in the Earth’s atmosphere, such as beryllium10. Beryllium-10 is a radioactive isotope with a short half-life, meaning it decays quickly.
The team’s results so far suggest that the production rate of cosmogenic radionuclides increased drastically due to the weak paleomagnetic field. The researchers also mentioned that the average production rate of beryllium-10 during the Laschamps event was double the current production, which suggests that the intensity of the Earth’s magnetic field is extremely low and that a lot of cosmic radiation is reaching our atmosphere – more than 40 thousand years ago.
In the press release, the research group concluded that the magnetosphere that protects the Earth has shrunk, which may have developed due to the reduction of the magnetic field, and this exposed our ancestors to extreme radiation, an effect that has subsided since the Laschamps event, but is still felt.
Conclusions
GFZ Potsdam researcher Sanja Panovska presented the new study to the European Geosciences Union – EGU for short – He will present it at his 2024 general meeting in Vienna, Austria. According to Panovska, understanding extreme events in Earth’s history is extremely important for future occurrence and estimation. Forecasting the space climate and assessing its effects on the Earth’s environment and wildlife are extremely important, as this could reduce future effects.
