For over 50 years, scientists have questioned whether supernovae blasted the planet with enough radiation to trigger mass extinction, influence human evolution and/or climate change.
Two new scientific studies have concluded that supernovae, shooting stars, have been hitting the Earth with radioactive isotopes, Iron-60, during the last few million years and have had some influence on Earth.
The first study drew this conclusion after studying supernovae debris, interstellar dust particles found in deep sea rock on the ocean floor. Researchers found Iron-60 while atom-counting measurements from 120 ocean bed samples from the Atlantic, Pacific and Indian oceans. Tiny quantities of this isotope were found in the Earth’s crust. The study indicates that one or more supernovae exploded about 2.2 million years ago. They conclused hat at the end of the Pliocene epoch, the Earth grew cooler. Though not causing extinction, the climate change probably brought about the rise of human linage.
The study’s lead author, Anton Wallner, a nuclear physicist at the Australian National University in Canberra, says,
It suggests there were a series of supernovae, one after another.
The study concludes,
Our findings indicate multiple supernova and massive-star events during the last ten million years at distances of up to 100 parsecs.
The second study used modeling to reach similar conclusions. Dieter Breitschwerdt at the Berlin Institute of Technology and his team spent years studying the “local bubble,” “a ballooning region (measuring 600 by 600 by 1,200 light years) of hot diffuse gas, 600 light years across, that surrounds our Solar System. The research concluded that it was created by a dozen supernovae exploding within a nearby clump of stars spreading Iron-60.
This may have affected the Earth’s climate and evolution of life but does not coincide with any mass extinction events. The study shows a peak occurring around 2 million years ago. According to research tables, the nearest blast in the simulation took place 2.3 million years ago, the second-nearest 1.5 million years ago. This calculation comes close to the estimates in the first study. It also concluded that the radiation explosions may have caused mutations in life forms on earth, influencing evolution.
Here we report calculations of the most probable trajectories and masses of the supernovae progenitors, and hence their explosion times and sites … We can make a table of stars – what mass they had when they exploded, and where they were.
It’s an interesting coincidence that they correspond with when the Earth cooled and moved from the Pliocene into the Pleistocene periods (epoch of ice ages that took place 2.5 million years ago).