About 41,000 years ago, the planet experienced a slight oscillation – not like noticing to the naked eye. In depth, the terrestrial magnetic field began to move, Disturbing the invisible shield which usually protects us from solar radiation.
The situation quickly became dangerous. Known as “laschamps excursion”, this temporary change in magnetic poles allowed harmful rays from the space to more easily cross the atmosphere, making large regions of the planet particularly hostile.
But according to new research by the University of Michigan, the first Homo Sapiens would have had a few tips to deal with it-especially relatively modern inventions such as clothes, cave shelters, and perhaps even a kind of prehistoric sunscreen.
Neanderthals, however? Not really.
A planet under dawn
Thanks to a complex modeling of spatial meteorological systems, the researchers reconstituted what the terrestrial magnetic field looked like at the time of the Laschamps event. Their 3D simulation revealed that the field had dropped to only 10 % of its usual strength, This considerably weakened the natural defense of the planet against harmful UV rays and cosmic particles.
This exhibition would have made solar radiation a serious threat to health and survival. But the study suggests that at the same time, Homo sapiens were starting to show signs of adaptation.
“We have found that many of these regions correspond quite closely to the areas of human activity dating from 41,000 years ago,” explains Agnit Mukhopadhyay, author of the study, “In particular an increase in the use of caves and the use of a form of prehistoric sunscreen. »»
This “sunscreen” was actually ocher – a red pigment known for blocking UVs – Found on archaeological sites alongside tools used to make custom clothing.
It was perhaps not voluntarily used as a sunscreen, But that worked, according to the researchers.
“It is a fairly effective sunscreen”, explains the anthropologist Raven Garvey. “Some populations studied in ethnography have even used it mainly for this purpose. »»
Clothing, needles and UV protection
If we think that the Neanderthals used skins, It was the homo sapiens who made clothes adjusted using alènes and needles – A modest, but crucial detail. According to the study, not only did it facilitate the exploration of cooler regions, but these additional layers also offered better protection against radiation.
However, scientists point out that their results remain correlational. But as Raven Garvey says: “I think it’s a new way of interpreting this data in the light of the Laschamps event. »»
Article reference:
Wandering of the auroral oval 41,000 years ago, published in Science Advances, April 2025.
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