Astronomers have detected the strongest radiation blast from deep space ever known, exceeding the power of 9,000 exploding stars.
The gamma ray burst occurred 12.2 billion light years away, and its light has taken most of the age of the universe to reach us. Scientists believe such bursts occur when stars run out of fuel and collapse to form a black hole.
It has been calculated that the material emitting the gamma rays must have been moving at 99.9999 per cent of the speed of light. The explosion was spotted by a Nasa telescope.