Far away supernova explosions could have played an evolutionary role. 2.59 billion years ago, the climate changed drastically. Africa dried out, and the forests turned into desert and savannah. Around this time our planet started having ice ages over and over again.
To date, it’s not clear why these things started to happen. Although controversial, cosmic rays may have played a role. A team of experts from Washburn University in Kansas made computer simulations which revealed how supernovas could affect Earth’s biosphere.
Supernovas happen in two ways: when a star with more mass than the sun runs out of fuel, or if a superdense star corpse called a white dwarf attracts matter from a nearby star that it causes it to explode.
Scientists have been focusing on supernovas which occur about 300 light-years from Earth.
They believe that these Supernova explosions may have ultimately led to the disappearance of a large number of ocean species.
At first, these supernovas led to disrupted circadian rhythms for animals. But 500 years later, they may have increased ionization in the atmosphere, which in turn could have triggered climate change.
Homo erectus, an early version of the human species, might have been put at a higher risk of cancer and mutations because of these supernovas.
Using computer model simulation, scientists were surprised to see supernovas affect life on Earth to a huge extent. Even though they are very far from us, at least 300 light-years away, they still influence things like radiation, and possibly evolution. This is why scientists believe that the two supernovae had huge effects on terrestrial atmosphere during the Early Pleistocene.
Apparently, cosmic rays of high-energy are rare on Earth. They get trapped at the higher altitudes of the atmosphere. But cosmic rays of high energy sometimes penetrate the atmosphere, tear up molecules, rip atoms apart, and that could have gone down to ground level.
For example, research suggests that supernovae may have caused a 20 fold increase in radiation on Earth. Climate change must have been a consequence of the increased level of radiation.
It’s not yet entirely clear how these radiations work, but scientists believe they led to climate change. Since then Earth has had multiple ice ages. So supernova explosions may have played an evolutionary role. And this is one of the possible explanations by top researchers.
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