Earth lives in a shooting gallery where celestial bodies like asteroids and supernova could hit the planet and potentially cause a cataclysmic event. A new study from Washburn University presents how different scenarios could end all life on Earth.

Supernova which occurs when a star explodes can emit lethal blasts of gamma-rays that can bathe the Earth in dangerous radiation. These gamma-ray bursts can emit the most harmful ultraviolet radiation that can penetrate the Earth's surface. In fact gamma-ray bursts have been responsible for some of the past extinction events in the Earth's history.

"We find that a kind of gamma ray burst -- a short gamma ray burst -- is probably more significant than a longer gamma ray burst," said astrophysicist Brian Thomas of Washburn University.

"The duration is not as important as the amount of radiation," said Thomas. Even a short gamma ray burst can have long lasting effects to the Earth's fragile ecosystem. A gamma-ray burst can cause ozone destroying nitrous oxides to form in the Earth's atmosphere. The long term result will be a depletion of the ozone layer which could be catastrophic to many of Earth's flora and fauna including mankind.

The SWIFT satellite has collected data that shows just how often the gamma-ray bursts occur in the galaxy. The galaxy actually experiences a gamma-ray burst once per 100 million years. Given the time period, it's likely that Earth has experienced a gamma-ray burst in its history. Such evidence of a gamma-ray burst could be found in the fossil record in isotope iron-60 which is a proxy for radiation events.

"I work with some paleontologists and we try to look for correlations with extinctions, but they are skeptical," said Thomas. "So if you go and give a talk to paleontologists, they are not quite into it. But to astrophysicists, it seems pretty plausible."