A gamma-ray burst (GRB) in our galactic neighbourhood could decimate life, destroy the ozone layer and trigger drastic climate change. A new study of Hubble data, published in Nature, has found such a cosmic deathray scenario is less likely than previous doomsday predictions.
The radiation the international team investigated comes with some of the biggest star explosions in the universe – long GRBs, which occur when a core-collapse supernova triggers an even more violent explosion.
More: http://www.theregister.co.uk/2006/05/11/grb_deathrays/