Gamma-ray burst, most powerful type of explosion in universe, may have hit Earth in 8th century

Zenaira Ali | Jan 21, 2013 6:38 PM ET | Last Updated: Jan 21, 2013 10:10 PM ET
More from Zenaira Ali | @thezenaira

NASA / AFP / Getty Images Files A      NASA image of the Earth from March 2, 2010. According to researchers, the Earth was hit with a gamma-ray burst in the 8th century.

 

Gamma-ray bursts are the brightest and most powerful explosions that happen in the entire universe. And German researchers are now saying one may have hit Earth in the 8th century.

This would be a rarity, as gamma-ray bursts once every 10,000 to one million years per galaxy. According to V. V. Hambaryan and R. Neuhauser’s research on this electromagnetic event, “this is the first evidence for a short gamma-ray burst in our galaxy.”

The researchers were led to this conclusion by their observation of elevated radiation levels around the world. Using aging techniques on ice and trees, researchers were able to track down what the levels looked like in 774 and 775 AD. In Japan, ancient trees had 20 times the expected amount of carbon-14, a radioactive type of carbon, while in Antarctica, there was a 30 per cent increase of beryllium-10 detected in ice.

Both of these isotopes are created when atoms in the upper atmosphere are hit with intense radiation. Professor Neuhauser told the BBC that a gamma-ray burst resulting in these elevated levels of isotopes is “fully consistent” with their research.

NASA / AFP / Getty Images   The sun unleashing a solar flare on June 7, 2011. Some researchers are saying that it is more likely the spikes in radiation around the world were caused by a solar flare.

 

These bursts of energy occur when black holes, neutrons or white dwarfs collide. Although the preliminary event takes seconds, they give off a huge wave of radiation.

Professor Adrian Melott from the University of Kansas told the BBC that although a gamma-ray burst is a possible explanation for the radiation, it is “about 10,000 times less likely to be true” than a solar flare event occurring in that time period.

Hambaryan and Neuhauser’s research indicates that although the explosion happened within our galaxy, it would have occurred 3,000 to 12,000 light-years away from the Earth. It is possible that humans at the time did not even notice it, as researchers do not believe any visible light was emitted.
If such an explosion were to take place today at just a few hundred light-years away, our ozone layer would be destroyed, which would have devastating effects for life on earth. But Professor Neuhauser told the BBC such an event “extremely unlikely.”

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