Monday, June 15, 1998 Published at 10:48 GMT 11:48 UK
What caused the biggest explosion ever seen?
A sky map showing the violent parts of the universe
Earlier this year, astronomers revealed that they had seen the biggest explosion in space since the big bang. Now they want to explain it. Our science correspondent David Whitehouse reports.
Scientists are gathering at a meeting of the American Astronomical Society in San Diego to try to work out what caused this gigantic explosion.
They had thought it was caused by the collision between two superdense stars, called neutron stars. But the explosion that was observed was too energetic to be explained that way.
Now astronomers believe that two black holes were involved.
Two black holes, each created by the explosion of a massive star that lived and died swiftly, approached each other.
It would have been an incredible sight. Each black hole, about the size of the Earth, would be totally black because no light can escape from a black hole, hence its name.
However if you could watch the black hole passing by you would see the light from distant stars distort as the black hole's gravity acted like a lens.
Around each black hole may have been a swirling disk of matter called an accretion disk.
The matter in this disk would be spiralling into the black hole like water down a plughole. The gas at the centre of this disk would be superhot, millions of degrees, and would radiate vast amounts of high energy radiation.
When the two black holes collided the release of energy was titanic. The shock waves rippled the very fabric of space-time, streams of particles were blasted into space as well as cascades of intense radiation.
More energy was released in one second than in all of the other objects in the universe combined.
The black hole collision idea may explain the explosion. Astronomers would like to spot another one so that they can test their ideas.