When solar radiation increased, these techniques may have helped our species spread across Europe and Asia.
Get the Popular Science daily newsletter💡 Email address Sign up Thank you! Terms of Service and Privacy Policy. Despite the sunscreen misinformation you might see online, ancient humans did face problems from the sun's harmful rays. Ancient Homo sapiens about 40,000 years ago may have even benefited from some of the same technologies that we use to avoid sunburns today–mineral sunscreen, tailored clothes, and using caves for shade and shelter. These advances may have been particularly advantageous when Earth's magnetic poles switched a bit, according to a study published April 16 in the journal Science Advances. Earth's history of polar reversals Earth's magnetic field is created by its rotation, as well as the rotation of our planet's core. The core, which is made up of molten iron, generates electrical currents. These currents extend a sort of halo around the globe that helps protect Earth from cosmic radiation. This radiation thins Earth's ozone layer and lets in more ultra violet (UV) and the interaction of these particles with the Earth's magnetic field also results in aurora. Currently, this magnetic field has a north and south orientation in the form of Earth's North and South poles. This is why you typically see auroras in regions close to the poles, where magnetic fields are the strongest. An artistic impression of what the aurora might have looked like on Earth about 41,000 years ago. CREDIT: Maximilian Schanner (GFZ Helmholtz Centre for Geosciences, Potsdam, Germany) Occasionally, these poles wander from their traditional geographic positions. These are called geomagnetic excursions. This natural process has occurred roughly 180 times over our planet's 4.5 billion-year geological history. Scientists believe that it is caused by some instability in the processes that generate Earth's magnetic field. The most recent geomagnetic excursion is called the Laschamps excursion and occurred about 41 to 42,000 years ago, when the magnetic North Pole began…