Vitor Paladini
By Stephen Beech
Cavemen were saved by using sunscreen more than 40,000 years ago, according to new research.
Ancient homo sapiens may have benefitted from mineral-based sun protection, living in caves and even tailored clothing during the shifting of the magnetic North Pole over Europe 41,000 years ago, say scientists.
But rival Neanderthals lacked the technologies to protect themselves from harmful solar radiation and disappeared around that time, suggests the study published in the journal Science Advances.
Researchers led by scientists from the University of Michigan found that the North Pole wandered over Europe when the magnetic field's poles started to flip positions, a natural process that has happened around 180 times over Earth's history.
While the magnetic reversal wasn't complete at the time, the magnetic field weakened to cause aurora to occur over most of the globe and allowed more harmful ultraviolet (UV) light to come in from space.
Around the same time, homo sapiens appear to have started making tailored clothing and using ochre - a mineral that has sun-protective properties when applied to the skin - with greater frequency.
Peter Burdon
Researchers believe those factors could have contributed to their spread throughout Europe and Asia at a time when the Neanderthal population was declining.
Study lead author Dr. Agnit Mukhopadhyay, a University of Michigan research affiliate, said: "We combined all of the regions where the magnetic field would not have been connected, allowing cosmic radiation, or any kind of energetic particles from the sun, to seep all the way in to the ground.
"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."
He explained that Earth's magnetic field is created by its rotation, and by extension, the rotation of its core.
The core, composed of molten iron, generates electrical currents, which extend in a halo around the globe.
That halo helps protect Earth from cosmic radiation which thins Earth's ozone layer and lets in more UV light.
The interaction of those particles with Earth's magnetic field results in aurora as well.
Dr. Mukhopadhyay developed a model that predicts how the plasma system interacts with Earth's magnetic field, ultimately driving the formation of the aurora.
He said the magnetic field has a north and south orientation: the North and South poles.
The orientation of the magnetic field is why you typically only see the aurora at the North and South poles, where magnetic fields are the strongest.
(Photo by Pixabay via Pexels)
But occasionally throughout history, the poles wander from their traditional geographic positions.
These are called "geomagnetic excursions" - with the most recent event called the Laschamps excursion, occurring around 41,000 years ago.
The research team found that during the Laschamps excursion, Earth's magnetic field reduced in size to about 10% of its current strength - allowing the magnetic poles to "droop" down near the equator and for its magnetic field lines to expand.
That would have also allowed aurora to be seen all over Europe and into northern Africa, according to the research team.
They then laid their 3D map of Earth's space system over the world and found that the time period of the Laschamps excursion - which lasted from about 41,000 to around 39,000 years ago - coincided with periods of change for groups of humans.
Dr. Raven Garvey, University of Michigan Associate Professor of anthropology, says Neanderthals and Homo sapiens coexisted in Europe, with Homo sapiens arriving roughly 56,000 years ago,
But, by around 40,000 years ago, Neanderthals were no longer identified as a species in Europe.
Dr. Garvey said: "What some of the differences are between these species, between Neanderthals and anatomically modern humans, that might account for that disappearance has been a major anthropological question for decades."
Azzedine Rouichi
She says clothing may have been a contributing factor as the means of producing clothes that fit the body has been discovered at archaeological sites associated with anatomically modern humans, but not necessarily Neanderthals.
Dr. Garvey says homo sapiens may have also "ramped up" their use of ochre, a naturally occurring pigment composed of iron oxide, clay and silica that has been used by many species of hominins for thousands of years.
She said: "There have been some experimental tests that show it has sunscreen-like properties.
"It's a pretty effective sunscreen, and there are also ethnographic populations that have used it primarily for that purpose.
"Its increased production and its association primarily with anatomically modern humans - during the Laschamps - is also suggestive of people's having used it for this purpose as well."
She added: "Having protection against solar radiation would also have conferred significant advantage to anyone who possessed it."
Dr. Mukhopadhyay said: "If such an event were to happen today, we would see a complete blackout in several different sectors.
"Our communication satellites would not work."
He added: "Many of our telecommunication arrays, which are on the ground, would be severely affected by the smallest of space weather events, not to mention the human impacts which would also play a pretty massive role in our day-to-day lives."
