Researchers says UV radiation caused by a polar shift may have taken out the Neanderthals

Cosmic energies are now thought to have had an incredible impact on human evolution and may have caused the Neanderthal extinction according to new studies.

We covered the first study that cosmic energy from supernovae may have caused early humans to stand upright as they adapted to atmospheric ionization which caused lightning storms and forest fires around the globe starting 8 million years ago. It was a case of “get up and run” as people had no choice but to escape torched forests for the savanna grasslands. There, Homo sapiens’ ancestors found an advantage in walking upright as they moved in the tall grass between trees.

Now another study shows that Earth’s geomagnetic field weakened 41,000 years ago, a time called the “Laschamp event” during the last ice age. During that time, the magnetic field weakened to just five percent of what it is today.

The magnetic field is always changing and occasionally the poles reverse, temporarily leaving the planet vulnerable to radiation. The Magnetic North Pole becomes the Magnetic South Pole and vice versa.

The weakened magnetic field allows UV radiation from the solar wind to bombard the planet, depleting the protective ozone layer. That radiation may have killed off the Neanderthals over generations as their DNA was damaged.

It has always been a mystery what may have caused the disappearance of the Neanderthals. Theories have abounded, suggesting that modern humans killed them off or that they couldn’t compete. However, there is no compelling evidence that proves there was an extinction event due to war or genocide. There is some evidence that early Denisovans, Neanderthals, and Homo Sapiens interbred, creating a hybrid species in one case.

So the obvious question is why did the surge in UV radiation kill the Neanderthals but not other early humans?

Florida geological sciences professor James Channell and Luigi Vigliotti of the Italian National Research Council’s Institute of Marine Sciences suggest it was due to the Neanderthal’s genome.

“Unlike Neanderthals, modern humans survived the prolonged UV radiation due to a key difference in their genome that better defended them from UVR. Scientists already knew that a protein called the aryl hydrocarbon receptor differed in Cro-Magnon and Neanderthals, but theorized the variation made Neanderthals more susceptible to environmental toxins such as those from cooking fires. Channell’s study — done with Luigi Vigliotti of the Italian National Research Council’s Institute of Marine Sciences — associates the different variants of AhR in Neanderthals and modern humans with different tolerance to UVR and correlates Neanderthal decline to weakened magnetic field and resulting UVR exposure.”

James Chanell said that the extinction was not immediate, but gradual over the over two and a half centuries of the relatively brief polar shift.

“The effect was not a blitzkrieg, but a process that affected the genome over time,” Channell said.

According to Newsweek, Channell has studied changes in the Earth’s magnetic field over 25 years. Scientists can track changes in magnetic field strength over time by taking samples from sea-floor sediments and ice cores as well as from satellite analysis. They found that there have been at least two times when Earth’s magnetic field became weak and caused extinction events: 40,000 years ago and 13,000 years ago. These periods coincided with two extinction events.

The Earth’s poles have reversed hundreds of times and scientists aren’t sure exactly when we will experience the next shift. The shifts seem to happen randomly but there are some scientists who believe we are already in the process of a polar shift.

Although a shift could potentially render parts of the planet uninhabitable, we might take some comfort in knowing that our ancient ancestors survived the Laschamp event. We might very well survive another polar shift, but may find ourselves adapting quickly to a world where modern electronics have been jammed by particles and radiation.

See more about polar shifts from Tech Insider below:

More on Neanderthals from National Geographic below:

Featured image: Screenshot via YouTube

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