Devonian mass extinction and the supernova

360 million years ago, one of the 5 mass extinction events that have devastated life on earth took place. With this event, the Devonian period would end. The Devonian was a period between the Carboniferous and the Silurian period in the Paleozoic era. During this period of extinction, 19% of all living being families would disappear, and 50% of all genus would get extinct.

To date, scientists keep debating about the cause of this mass extinction. Among some of the hypotheses are; the impact of an asteroid, and the rapid evolution of plants that unleashed a series of changes in atmospheric chemistry.

Recently, a group of scientists published, in the Proceeding of the National Academy of Sciences, a new hypothesis. They propose that an astrophysical phenomenon could have been among the causes that led to the mass extinction. Specifically, they point to a supernova explosion that occurred at 20 parsecs or 65.2 light-years of distance from Earth. This explosion could have added up to all the other changes happening at that time.

Brian D. Fields, lead author of the paper, and his team of researchers suggest that the explosion could have accelerated cosmic rays like Muons. These cosmic rays created ionizing radiation on Earth for 100 000 years. The radiation caused a decrease in the ozone layer in the atmosphere, and with it, a mass extinction.

In the image below, you can see a hydrodynamic simulation of the explosion made by the researchers. The simulation shows the shock waves from the supernova explosion hitting the solar wind of our solar system. The dashed blue ring represents Earth's orbit at the time, and the red dot at the center is our sun.

To test their hypothesis, the researchers are looking for radioisotopes of \({}^{145}Sm\) Samarium or \({}^{244}Pu\) Plutonium in the ground. If their hypothesis is true, these two radioisotopes would be present in late Devonian strata.

This would also prove the supernova nucleosynthesis. A process by which you can create new atoms from a supernova explosion and pre-existing atoms.

This is not the only way to prove or disprove their hypothesis, so the researchers call out to the scientific community to find out other ways to test their hypothesis.

Credit Jesse A. Miller y Brian D. Fields