When gigantic stars run out of fuel they collapse under their own gravity and, in a last hurrah, send out a blast of light and matter in the most violent known explosions in the universe.

Now astronomers have discovered that these cataclysmic events, known as gamma ray bursts, release roughly twice as much energy as previously thought.

The rethink comes after an international team registered a record-breaking observation of the highest-energy radiation ever measured from gamma ray bursts.