Many people wonder what was the event that triggered the important milestone in human evolution, causing ancient humans to walk upright. A new study sheds light on this event, suggesting that an ancient supernova event caused humans to walk upright.
According to a study published in the Journal of Geology, there were supernovae that hit Earth with cosmic energy and rays 8 million years ago, reaching its peak 2.6 million years ago, caused swarms of electrons in the lower atmosphere, causing events that impacted our evolution and caused bipedal hominins like homo habilis.
“It is thought there was already some tendency for hominins to walk on two legs, even before this event,” lead author Adrian Melott, professor emeritus of physics & astronomy at the University of Kansas said in a statement. “But they were mainly adapted for climbing around in trees. After this conversion to savanna, they would much more often have to walk from one tree to another across the grassland, and so they become better at walking upright. They could see over the tops of grass and watch for predators. It’s thought this conversion to savanna contributed to bipedalism as it became more and more dominant in human ancestors.”
Scientists focused on a “telltale” layer of iron-60 deposits which are located in the lining of the world’s sea beds. That made scientists theorize that the supernovae exploded somewhere in Earth’s cosmic neighborhood, at about 100 to 50 parsecs (equivalent to 163 light years) away, during the time when ancient humans progressed from the Pliocene Epoch to the Ice Age.
“We calculated the ionization of the atmosphere from cosmic rays which would come from a supernova about as far away as the iron-60 deposits indicate,” Melott said. “It appears that this was the closest one in a much longer series. We contend it would increase the ionization of the lower atmosphere by 50-fold. Usually, you don’t get lower-atmosphere ionization because cosmic rays don’t penetrate that far, but the more energetic ones from supernovae come right down to the surface—so there would be a lot of electrons being knocked out of the atmosphere.”
Melott and co-author of the study Brian Thomas of Washburn University believe that ionization in the lower atmosphere caused electrons to spread out, making more pathways for lightning strikes on Earth, adding that the probability of lightning spikes touching off a worldwide wildfire is supported by huge carbon deposits in the soils.
However, Melott said that it’s unlikely that such an event which could have caused ancient humans to walk upright is going to happen again any time soon. The nearest star with the possibility of exploding into a supernova in the next million years (Betelgeuse) is located 200 parsecs (652 light years) from our planet, which is unlikely to affect us in such a way.
“Betelgeuse is too far away to have effects anywhere near this strong,” Melott said. “So, don’t worry about this. Worry about solar proton events. That’s the danger for us with our technology—a solar flare that knocks out electrical power. Just imagine months without electricity.”