Early Homo sapiens may have gained advantages from sunscreen, customized garments, and the utilization of caves during the migration of the magnetic North Pole across Europe approximately 41,000 years ago, recent research from the University of Michigan indicates.
These innovations likely shielded Homo sapiens residing in Europe from damaging solar radiation. Conversely, it seems that Neanderthals did not possess such technologies and vanished roughly 40,000 years ago, as per the findings published in Science Advances by researchers at Michigan Engineering and the U-M Department of Anthropology.
The research team discovered that the North Pole traversed Europe as the magnetic field’s poles began to shift positions, a natural occurrence that has taken place around 180 times throughout Earth’s geological record. Although the magnetic reversal did not complete during that period, the magnetic field weakened enough to produce auroras across a vast portion of the globe, consequently permitting more harmful UV radiation to penetrate from space.
Simultaneously, it appears that Homo sapiens began creating tailored attire and applying ochre, a mineral with sun-shielding qualities when used on the skin, more frequently. These practices may have aided in their expansion across Europe and Asia while the Neanderthal population was on the decline.
“In this research, we examined all the areas where the magnetic field would not have been connected, permitting cosmic radiation or any kind of energetic particles from the sun to seep entirely into the ground,” mentioned Agnit Mukhopadhyay, the lead author and U-M research affiliate in climate and space sciences and engineering.
“Our findings indicate that numerous regions align closely with early human activities from 41,000 years ago, particularly a rise in the use of caves and an increased application of prehistoric sunscreen.”
Shifting Poles
The magnetic field of Earth is produced by the movement of molten metals in its outer core. These movements create electric currents, consequently generating a magnetic field that extends in a halo around the planet. This protective halo shields Earth from cosmic radiation, which depletes the ozone layer and admits more UV light. The interaction of these particles with Earth’s magnetic field also leads to the formation of auroras.
Mukhopadhyay initiated the development of models illustrating this interaction using the Space Weather Modeling Framework, a flexible numerical tool introduced and maintained by the U-M Center for Space Environment Modeling, designed for studying the sun, heliosphere, and planetary space environments, including Earth’s.
The sun consistently emits heated gases and charged particles toward Earth, which, due to their incredibly high temperatures, behave as a plasma system. Mukhopadhyay developed a model estimating how this plasma system interacts with Earth’s magnetic field, ultimately influencing the formation of the auroras.
This magnetic field possesses a north and south orientation: the North and South poles. The orientation of the magnetic field is responsible for the visibility of auroras primarily at the North and South poles, where magnetic fields are most potent. However, throughout history, these poles occasionally drift from their usual geographic locations. Mukhopadhyay refers to these occurrences as “geomagnetic excursions.” The latest known event is termed the Laschamps excursion, which transpired approximately 41,000 years ago.
Collaborating with Sanja Panovska, a scientist at Germany’s GFZ Helmholtz Centre for Geosciences, Mukhopadhyay crafted a 3D portrayal of Earth’s geospace system. Achieving this required combining three distinct models: one global model that reconstructs the geomagnetic field during the Laschamps excursion, a model of the space plasma environment surrounding Earth, and a model that predicted the appearance of Earth’s aurora during that time. The resultant 3D model illustrated where charged particles could penetrate Earth’s geomagnetic field.
The researchers discovered that during the Laschamps excursion, Earth’s magnetic field diminished to about 10% of its current strength, allowing Earth’s…
This would cause magnetic poles to sag near the equatorial region and permit the magnetic field lines to stretch outward. As a result, auroras could be visible across Europe and extending into the northern regions of Africa.
The scientists subsequently superimposed their three-dimensional representation of Earth’s spatial system onto the globe, discovering that the period of the Laschamps excursion—spanning approximately 41,000 to 39,000 years before present—aligned with transformation phases for various human groups inhabiting the Earth.
Cosmic rays, radiation, and survival
Neanderthals and Homo sapiens cohabited Europe, with Homo sapiens—often referred to as anatomically modern humans—making their appearance around 56,000 years ago, as stated by Raven Garvey, an associate professor of anthropology at the University of Michigan. By roughly 40,000 years ago, Neanderthals had ceased to be recognized as a species in Europe.
“The distinctions between these species, particularly between Neanderthals and anatomically modern humans, that might explain their extinction have remained a significant anthropological inquiry for many years,” Garvey noted.
Apparel may have played a crucial role, she suggested. The technological advancements for creating clothing that conformed to the body have been unearthed at archaeological locations linked with anatomically modern humans, but not necessarily with Neanderthals.
At sites tied to anatomically modern humans, archaeologists have uncovered not only tools for hide preparation but also needles and awls—items associated with the art of sewing. Garvey explains that fitted clothing provides a dual benefit: it offers considerable warmth and permits individuals to venture further from their fires and shelters in search of sustenance.
Additionally, tailored garments might have unwittingly offered another advantage—protection from the sun, she mentioned.
Solar radiation poses numerous harmful effects, including eye disorders and folate depletion (which can result in congenital anomalies and heightened infant mortality), “thus, having defense against solar radiation would have granted considerable benefits to anyone with it,” Garvey remarked.
Homo sapiens may have also amplified their use of ochre, a naturally occurring colorant made of iron oxide, clay, and silica that has been utilized by various hominin species for a lengthy period. It was used for coloring objects, cave walls, and even for body decoration.
“Experimental tests have demonstrated that it possesses sunscreen-like properties. It serves as an efficient sunscreen, and there are also ethnographic groups that have applied it primarily for that reason,” Garvey noted. “The increased production of ochre and its primary association with anatomically modern humans (during the Laschamps) suggests that it was utilized for this purpose as well.”
Finding caution in the (solar) wind
The researchers emphasize that their conclusions are not conclusive. However, they represent a novel approach to interpreting existing data.
“It’s vital to acknowledge that these findings are correlational and represent a meta-analysis,” Garvey stated. “Yet, this provides a new perspective on the data when considering the Laschamps excursion.”
Alongside investigating how past excursions could have influenced humans long ago, Mukhopadhyay indicated that the three-dimensional model enables predictions on how similar excursions may impact us moving forward.
“If a comparable event were to occur today, we would face a total blackout across several sectors,” he explained. “Our communication satellites would cease functioning. Numerous terrestrial telecommunication systems would be severely impacted by even minor space weather incidents, let alone the significant human consequences on our daily lives.”
Mukhopadhyay also highlighted that their research illustrates that humans managed to endure on a planet with an atmosphere dramatically dissimilar to ours today, which carries implications for the search for life on extraterrestrial planets.
“Many assert that a planet cannot support life without a robust magnetic field,” he stated. “Studying prehistoric Earth, especially events like this, provides us with a unique perspective on exoplanetary physics. Life did exist back then, albeit in forms that were different from the present.”
Co-authors of the study include Michael Liemohn, Daniel Welling, and Austin Brenner from Michigan Engineering, Natalia Ganjushkina from both Michigan Engineering and the Finnish Meteorological Institute, Ilya Usoskin from the University of Oulu, and Mikhail Balikhin from the University of Sheffield.
