Did ancient supernova cause humans to walk upright? New Study resolves mystery

A study claims that a supernova millions of years ago caused environmental changes that helped humans evolve to walk upright.

Cassiopeia A
This false-color image from three of NASA Great Observatories provides one example of a star that died in a fiery supernova blast. Called Cassiopeia A, this supernova remnant is located 10,000 light-years away in the constellation Cassiopeia. NASA/JPL-Caltech/STScI/CXC/SAO

A new study claimed that an ancient supernova played a huge role in the evolution of humans. According to the authors of the study, the effects of the supernova triggered environmental changes that caused humans to walk upright.

A link between a supernova and the evolution of human bipedalism may seem a bit far-fetched but for authors of a new study, the massive cosmic event affected the environmental conditions on Earth. This then led to the early humans adapting to their new environment. Eventually, as the early humans got used to their surroundings, they started walking upright on two legs.

According to the authors of a study, a supernova that occurred millions of years ago showered its surroundings with high-energy cosmic rays. The emissions from the supernova, which was estimated to be about 150 to 300 light-years away, eventually reached Earth. As they hit Earth, the energetic particles from the cosmic rays affected the planet's atmosphere, causing a sudden spike in lightning strikes.

The Neanderthals
An exhibit shows the life of a neanderthal family in a cave in the new Neanderthal Museum in the northern town of Krapina February 25, 2010. Reuters

"We build on previous work to argue for the likelihood of cosmic ray ionization of the atmosphere and electron cascades leading to more frequent lightning and therefore an increase in nitrate deposition and wildfires," wrote in the study, which was published in the journal Nature.

"The potential exists for a large increase in the pre-human nitrate flux onto the surface, which has previously been argued to lead to CO2 drawdown and cooling of the climate."

During ancient times when Earth's landmasses are mostly covered in forests and thick vegetation, lightning strikes are known to be the primary cause of wildfires. According to the study, the wildfires ignited by lightning cleared vast areas of forests, leaving behind clear regions free of vegetation. This provided early humans with a new environment for hunting prey.

The authors of the study claimed that through clearer surroundings, early humans discovered that they can spot prey from great distances if they stand up. The new environment also allowed them to learn that they can catch their prey by running on two legs. Eventually, this led to a major milestone in the evolution of humans.

"The wildfires would have contributed to the transition from forest to savanna in northeast Africa, long argued to have been a factor in the evolution of hominin bipedalism," the study's authors explained.

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