Posted on 04/06/2003 3:48:27 PM PDT by Davea
A billion-sun blast
By Richard Macey
April 2 2003
Anyone watching the sky late on Saturday night could have witnessed one of nature's most violent events since the Big Bang 13 billion years ago.
In a galaxy 2 billion light years away, a giant star had exploded and collapsed, giving birth to a black hole. The blast released almost unimaginable amounts of energy.
"During the first minute after the explosion," said Michael Ashley, head of astrophysics at the University of NSW, it "emitted energy at a rate more than a million times the combined output of all the stars in the Milky Way".
"If you concentrated all the energy that the sun will put out over its entire 9 billion-year life into a tenth of a second, then you have some idea of the brightness..."
Associate Professor Ashley said it was amazing to think that the star had exploded 2 billion years ago and that its light had been "racing across the universe ever since".
"On Saturday night at 10.37pm, it reached the Earth, and it would have been visible for perhaps a minute as a medium brightness star in the northern sky above Australia."
The starlight faded rapidly, vanishing without trace, but fortunately a NASA satellite had leapt into action, beaming news of the blast - designated Gamma Ray Burst 030329 - to a United States ground station.
A message was then flashed to Siding Spring, in northern NSW, alerting Professor Ashley's team, which just three days earlier had commissioned a new telescope designed to hunt gamma ray bursts - ROTSE-lll (Robotic Optical Transient Search Experiment).
"We saw a very bright new star," he said, estimating that the initial blast was 100 times brighter than any gamma ray burst previously seen.
"It was already too faint to see in binoculars but a medium amateur telescope would have easily seen it.
"We are extremely excited, it was an amazing event. We estimate that such an event occurs maybe once in 10 years."
Gamma ray bursts were unknown until 1967, when US military satellites monitoring nuclear tests noticed far bigger explosions in deep space. Three years ago, astronomers agreed they are caused by hypernovas - explosions of stars 50 to 100 times the size of our sun - in distant corners of the universe.
A hypernova can produce a black hole in "a fraction of a second", Professor Ashley estimates.
"During this process a staggering amount of energy is funnelled into two deadly cones of radiation. Any civilisation that found itself aligned with one of these cones, and within about 3000 light years of the hypernova, would be wiped out.
"We expect a hypernova to occur in our own galaxy roughly every 200 million years. Fortunately, our galaxy is a large place and the chances of being within 3000 light years of a hypernova are quite small."
'Unchanging Heavens' bump. I wonder if any UFO sightings in the past decades can be attributed to astronomical phenomenon. "I saw a bright light that seemed to hover, and then disappear . . . . "
Thanks for putting our minds at ease.
Thanks for putting our minds at ease.
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Oh, darn! I guess that means I gotta go and vacuum anyway, huh?
Maybe so, but I'm getting under the bed just in case.
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