Gamma-ray burst 'hit Earth in 8th Century'

In 2012 researchers found evidence that our planet had been struck by a blast of radiation during the Middle Ages, but there was debate over what kind of cosmic event could have caused this.

Now a study suggests it was the result of two black holes or neutron stars merging in our galaxy.

http://www.bbc.co.uk/news/science-environment-21082617