Aussies spy 'birth' of black hole

Explosion is the bright spot in the centre
[Image: Mt Stromlo/Siding Spring Observatories]

Australian astronomers believe they are the first people to observe the birth of a black hole.

No-one has witnessed such an event before. The phenomenon is caused by a huge star collapsing in on itself.

The remarkable sighting could be the key to explaining the enigmatic gamma-ray bursters, the most powerful explosions in the Universe since the Big Bang.

Eta Carinae: A star on the brink of destruction

Telescopes of both the Anglo-Australian Observatory and the Commonwealth Scientific and Industrial Research Organisation (Csiro) are trained on the spectacular fireball.

The fireball looks like a supernova, a gigantic explosion that ends the lives of stars many times bigger than our Sun.

Supernova are well-studied. But there is a one-in-a-million chance of an exploding star being so massive that the objects innards are crushed into a black hole.

Such a possibility was predicted more than a decade ago but no-one knew what it looked like. They may do now.

First clues

The first inkling was a blast of gamma rays spotted by the Italian-Dutch BeppoSAX satellite on 25 April.

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As this blast happened in the southern sky, telescopes in Australia and Chile swung into action looking for light waves.

Such alerts are frequent but often end in disappointment with nothing being detected.

Dr Mark Wieringa, of the Csiro's Australia telescope, said: "We've done two or three in the last year without success."

The Mount Stromlo Observatory, near Canberra, became the first to pick up light from the fireball.

Then on 2 May, the Anglo-Australian telescope, near Coonabarabran, got a spectrum of light.

This was used to work out the distance to the fireball, some 100 million light years.

A light year is the distance light travels in 12 months at 300,000 kilometres (186,000 miles) a second.

Cruel nature

Director of the Csiro Australia Telescope Ron Ekers said: "This is only the third gamma-ray burster that anyone has been able to see radio waves from."

Unlike other gamma-ray bursters, this one is not fading but growing stronger, astronomers say.

Mr Ekers said: "This one is already 10 times stronger. It's doubled in strength since last week and is still increasing."

Elaine Sadler, of the University of Sydney, said: "It could be the death of a really giant star, up to 100 times the mass of the Sun."

But Dale Frail of the US National Radio Observatory has struck a note of caution. He said whatever astronomers were seeing could be two separate events, a gamma-ray burster and a supernova nearby.

He said: "Nature can be cruel. It has done this to me before."