Blast from the past: gamma-ray burst strikes Earth from distant exploding star

An enormous burst of gamma rays, detected by ESA’s Integral space telescope, has struck Earth. The blast caused a significant disturbance in our planet’s ionosphere. Such disturbances are usually associated with energetic particle events on the Sun but this one was the result of an exploding star almost two billion light-years away. Analysing the effects of the blast could provide information about the mass extinctions in Earth’s history.