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Saturday, 9 May, 1998, 02:22 GMT 03:22 UK
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.
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.
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."
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