The Earth’s magnetic field protects us from harmful high-speed particles from the Sun. Credit: Getty Images/MARK GARLICK/SCIENCE PHOTO LIBRARY
A blip in Earth’s magnetism tens of thousands of years ago may have exposed humans in Northern Europe to dangerously high levels of solar radiation, making some groups seek shelter and even cover their skin with paint and other materials.
Researchers from the University of Michigan in the US mapped a shift in our planet’s field known as the Laschamp event, where the magnetic poles drifted out of their usual spots over the northern and southern ice caps.
The timing and location of the north magnetic pole’s movements neatly match changes in the way our ancestors housed and dressed themselves, as well as the disappearance of our close cousins – the Neanderthal.
Of course, the Laschamp event and appearance of new Ice Age fashion could just be a curious coincidence. But the researchers think the fact both occurred in northern Europe 41,000 years ago might be important.
“We found that many of those regions actually match pretty closely with early human activity from 41,000 years ago, specifically an increase in the use of caves and an increase in the use of prehistoric sunscreen,” says Agnit Mukhopadhyay, a researcher in climate and space sciences and engineering.
Earth’s magnetic field shields its atmosphere from showers of charged particles that blast out of the Sun, channelling them like rain drops over the edge of an umbrella towards the poles. When these high-speed particles crash into the air, they can cause the gases to glow in what we call aurorae.
They can also force some gases, like ozone, to break apart and allow UV radiation to shine through more easily.
Using different models of Earth’s past, Agnit and his team created a detailed description of a brief ‘wobble’ in the magnetic field, revealing the poles may have moved and guided showers of particles from the Sun onto the atmosphere in Northern Europe, and how the field may have weakened by around 10 percent.
The team suggests humans living in the area could have avoided the extra sunburn by building better clothing and covering their skin in ochre. If Neanderthals didn’t do as good a job at slip-slop-slapping, it could help explain why they all died out shortly after this event.