Seeing stars after a big bang

The dying embers of the explosion seen by the Hubble Space Telescope

Astronomers have witnessed the biggest explosion since the big bang that created the cosmos. Our science correspondent David Whitehouse reports.

The huge explosion, coming from a point near the edge of the observable universe, released more energy in one second than all the other objects in the universe combined.

It was initially detected as a burst of gamma rays, high energy radiation, picked up by an orbiting satellite.

Thousands of so-called gamma ray bursts have been detected. Astronomers know they must come from far away but this is the first time that the distance to one has been determined.

The distance measurement was possible because four months later the Hubble Space Telescope was able to see the afterglow of the explosion and estimate its distance by analysing its light.

Close up of the fading explosion

The explosion occurred about 12 billion light years away and therefore not long after the origin of the universe 15 billion years ago.

Combined with the observed brightness of the blast, this large distance implies an enormous energy release.

Finding such an energetic explosion is unprecedented in astronomy except for the Big Bang itself. The explosion has been called Big Bang 2.

It is believed that this titanic release of energy occurred when two spinning black holes collided with each other, explosively turning matter into radiation.

"In a region about a hundred miles across, the burst created conditions like those in the early universe," said Professor George Djorgovski of the California Institute of Technology.

The research is published in the science journal Nature.

Scientists hope that this explosion will shed light on the earliest stages in the evolution of stars and galaxies.