Gamma Ray Bursts, Supernovae in Space: Could They Have Catastrophic Effects on Earth?

Gamma ray bursts and supernovae often occur outside the Earth's galaxy, but is it possible for these distant events to cause destruction in the planet - maybe even cause mass extinction? Scientists take a closer look.

According to a report from Phys Org, the Ordovician mass extinction 450 million years ago wiped out a significant number of the marine species population. It's one of the five major extinctions in the planet's long history, and there are theories that point to a gamma ray burst as one possible trigger to this infamous event.

Known to be the brightest electromagnetic blasts in the universe, gamma ray bursts can come from the collapse or collision of stars. On the other hand, supernovae are stellar explosions. Both events often occur in distant galaxies, but they have terrifying consequences at a lesser distance. Gamma ray bursts and supernovae can destroy the protective ozone layer, which will leave the planet vulnerable to ultraviolet radiation from the sun. This creates what is called ground-level ozone.

In a new study published in Astrobiology, Washburn University astrophysicist Brian Thomas and his colleague Byron Goracke studied the potential of this ground-level ozone as a biological threat. They did this with a model simulating a gamma ray burst in the South Pole.

The team found that a burst concentrated in the South Pole would produce 10 parts per billion (ppb) amount of ozone in the lower atmosphere, which would not be enough to amplify risk of death through respiratory failure in humans. For this to occur, around 30 ppb is necessary, which is about the same amount for the ozone to damage the plant population as well.

This amount of ozone dissolved in the ocean would also have only a minimal impact on marine life, confirming that a gamma ray burst likely did not cause the Ordovician mass extinction millions of years ago.

Still, even if the ground-level ozone will not instantly cause a massive loss of life, the destruction of the ozone layer and the entry of ultraviolet radiation are going to be dire for life throughout the planet.