A new study claimed that a supernova that occurred millions of years ago triggered an important atmospheric event on Earth that helped in the evolution of humans. According to the study, the ancient supernova caused environmental conditions that led to humans walking on two legs.

In the study, the authors explained that a dying star went supernova millions of years ago. The massive cosmic explosion sent highly charged particles into space. The emission from the supernova, which was about 150 to 300 lights years away from the Solar System, eventually reached Earth.

The energetic cosmic particles produced from the supernova entered Earth and interacted with its atmosphere. Due to the increased presence of high-energy particles in the atmosphere, lightning strikes became more frequent.

During the time when Earth’s land regions are mostly covered by thick vegetation and forests, lightning strikes can easily cause wildfires to ignite. Due to the increase in the frequency of lightning strikes, wildfires in various areas burned down forests and cleared vast areas.

“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,” the authors wrote in the study, which was published in The Journal of Geology.

“The potential exists for a large increase in the prehuman nitrate flux onto the surface, which has previously been argued to lead to CO2 drawdown and cooling of the climate,” they added.

The new surroundings provided ancient humans with a different hunting ground. It helped them adapt by learning that they can spot prey at great distances if they stand upright. The new surroundings also helped them be able to run faster on two legs. Eventually, their new hunting strategies helped them evolve and adopt a bipedal stance

“Evidence for increased wildfires exists in an increase in soot and carbon deposits over the relevant period,” the researchers stated. “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.”

Supernova remnant
Supernova remnants are the debris from exploded stars. G292.0+1.8 is a rare type of supernova remnant observed to contain large amounts of oxygen. Because they are one of the primary sources of the heavy elements (that is, everything other than hydrogen and helium) necessary to form planets and people, these oxygen-rich supernova remnants are important to study. The X-ray image of G292+1.8 from Chandra shows a rapidly expanding, intricately structured field left behind by the shattered star. The image is colored red, green, teal and purple in X-rays ranging from the lowest to highest energy levels.Recently the first detection was made of iron debris from the exploded star. Authors constructed a map of this debris, along with that of silicon and sulphur, to understand more about the explosion. They found that these three elements are mainly located in the upper right of the remnant. This is in the opposite direction from the neutron star that was formed in the explosion, and was then kicked towards the lower left of the remnant. This suggests that the origin of this kick is gravitational and fluid forces from an asymmetric explosion. If more than half of the star’s debris is ejected in one direction, then the neutron star is kicked in the other direction so that momentum is conserved. This finding argues against the idea that the copious amounts of neutrinos formed in the supernova explosion were emitted in a lop-sided direction, imparting a kick to the neutron star. NASA/CXC/SAO
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