The ancient earth was a much more hostile place than it is today. About 42,000 years ago, the Earth saw its magnetic poles flip. Scientists have known that the magnetic poles of the earth flipped since the late 1960s. The magnetic poles aren’t static. The poles are generated by electrical currents from the planet’s liquid outer core that is constantly in motion.
The last pole flip wasn’t believed to have had a major environmental impact. The magnetic field did get weaker and allowed more cosmic rays to reach the planet’s surface. Despite being bathed more cosmic rays, plant and animal life isn’t believed to have been significantly impacted. However, a new study has found that the additional cosmic raise may have depleted ozone concentrations and allowed more ultraviolet radiation through the atmosphere.
The researchers believe that contributed to changing weather patterns that may have expanded the ice sheet over North America while drying out Australia. This could have prompted the extinction of many large species on the planet. The study authors also believe a solar storm could have driven ancient humans into caves for shelter. According to the study, competition for resources between remaining species could be the reason Neanderthals went extinct.
So far, scientists have been unable to come to a consensus on what led to the extinction of the Neanderthal. Some past research has suggested that the extinction happened naturally due to inbreeding with modern humans. Others believe that Neanderthals could have been out-competed for resources as modern humans began to rise in numbers. Researchers on the new study believe it’s not a coincidence that the Neanderthals died out directly after a major shift of the planet’s magnetic poles.
Researchers turned to the ancient kauri tree that was alive at the time of the Neanderthals looking to its rings for record of radiocarbon levels. The rings showed evidence of rising radiocarbon when the magnetic fields flipped, which is known as the Laschamps excursion. The team believes that event could have contributed to the fall of the Neanderthals, but they admit it’s hard to know exactly when they died out.