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Did the old supernovae cause proto-humans to walk on two legs, leading Homo sapiens with hands free to build cathedrals, design rockets and photograph selfies for iPhone?
An article published today in the Journal of Geology explains: Supernovae bombed the Earth with cosmic energy beginning 8 million years ago, with a peak of 2.6 million years ago, triggering an avalanche of dolphins. electrons in the lower atmosphere and triggering a series of events that ended in biped hominines. such as Homo Habilis, nicknamed "the practical man".
The authors believe that atmospheric ionization has probably caused a considerable upsurge in ground cloud lightning that has triggered wildfires around the world. These hells could be one of the reasons of the ancestors of Homo sapiens biped developed – to adapt to the savannas that have replaced the burned forests of northeastern Africa.
"It is thought that hominines already tended to walk on two legs, even before this event," said lead author Adrian Melott, professor emeritus of physics and astronomy at the University of Kansas . "But they were mostly adapted to climb trees, and after this conversion to savannah, they had to walk a lot more often from one tree to another across the meadow, and they were better able to walk upright. They could see over the tops of the grass and watch the predators.This conversion to savannah would have contributed to bipedalism as it would become more and more dominant among human ancestors. "
Based on a "revealing" layer of iron deposits 60 covering the seabeds of the world, astronomers have a highly exploded supernova of confidence in the immediate cosmic vicinity of the Earth – between 100 and 50 parsecs (163 light-years) – during the transition from the Pliocene Epoch to the Ice Age.
"We calculated the ionization of the atmosphere by the cosmic rays that would come from a supernova about as far as the iron-60 deposits indicate," said Mr. Melott. "It seems like it's the closest of a much longer series.We think it would increase 50-fold the ionization of the lower atmosphere.Usually, the ionization of the lower atmosphere n & # 39; 39 is not obtained because cosmic rays do not penetrate far, but the most energetic supernovae descend to the surface – so many electrons would be driven out of the atmosphere. "
According to Melott and his co-author Brian Thomas of Washburn University, ionization in the lower atmosphere meant that an abundance of electrons would form more lightning propagation pathways.
"The low kilometer or more of the atmosphere is affected in a way that it normally never undergoes," Melott said. "When high-energy cosmic rays strike atoms and molecules in the atmosphere, they expel electrons – so these electrons run in bulk instead of being bonded to atoms. the lightning process, there is a build-up of tension between clouds or clouds and the ground – but the current can not flow because there are not enough electrons to carry it, so it must accumulate High voltage before the electrons move.Once they move, the electrons expel more electrons of more atoms, and this becomes a flash.But with this ionization, this process can be started much more easily, so that there would be many more flashes. "
The KU researcher said that the discovery of carbon deposits in soils corresponding to the moment of cosmic-ray bombardment confirmed the likelihood that this lightning surge would trigger an upsurge in global fires.
"The finding is that there is a lot more charcoal and soot in the world from a few million years ago," Melott said. "It's everywhere, and no one knows why it would have happened anywhere in the world, in different climate zones." This could be an explanation. </ P> <p> It is believed that this increase in fires has stimulated the transition of forests to the savannah. of regions – where there were forests, now there were mostly open and shrub-like meadows, which would be linked to human evolution in North-East Africa, specifically in the Great Rift Valley, where find all these fossils of hominins. "
Melott said that no such event would happen again The nearest star able to explode in supernova over the next million years is Betelgeuse, at some 200 parsecs ( 652 light-years) from the Earth.
"Betelgeuse is too far to have effects close to this fort," Melott said. "So, do not worry about that, worry about solar proton events, that's the danger to us with our technology – a solar flare that cuts off the electrical power, imagine months without electricity."
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Material provided by University of Kansas. Note: Content can be changed for style and length.
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