Stargazers Hitch High Hopes To New Wave Of Astronomy
Sydney Morning Herald
Sunday May 29, 1994
Astronomers are on the verge of finding a new way to view the universe. It may rival Galileo's invention of the telescope.
If they can show that gravity waves - vibrations which travel harmlessly through space - can be detected, they will have another means to map distant parts of the universe.
For the past four months, physicists at the University of Western Australia, the University of Rome and Louisiana State University have been jointly searching for gravity waves created by stars collapsing in the centre of the Milky Way to form black holes.
The waves were first proposed by Einstein in his Theory of Relativity but no-one has ever detected one.
Last year two American astronomers won a Nobel Prize for proving they existed. But they only observed the effects of the waves on two distant stars spiralling towards each other.
Associate Professor David Blair, of the Department of Physics at the University of Western Australia, which has built the most sensitive gravity wave detector in the world, said yesterday mapping the vibrations would give science new eyes to observe the sky.
"It will mean the start of gravitational astronomy," said Associate Professor Blair. "We want to make the first survey of the rate of gravitational wave events. We don't really know what to expect but we know the universe is a lot more exotic than we can ever imagine."
The West Australian detector consists of a three-metre bar of niobium - the biggest lump of the metal in the world - cooled by liquid helium to almost absolute zero.
The bar is inside a vacuum cylinder and the machine is mounted on equipment designed to dampen vibrations of earthly origins.
Associate Professor Blair said niobium did not absorb sound. "If you dong it like a bell it will ring for a week," he said.
The physicists hope gravity waves pouring out of black holes being born at the centre of the galaxy will set the niobium bar ringing just enough for the vibrations to be measured.
Most vibrations detected have local causes. But any simultaneously recorded in Perth, Rome and Louisiana would have to be considered suspicious. Using triangulation, the physicists will be able to work out if the waves are from deep space.
On June 15 the scientists will gather in Rome to compare data. Associate Professor Blair warned the first look would probably reveal nothing. "It could take a month ... it could take years."
If the vibrations can be observed, gravity wave "telescopes" may be possible. He said the ultimate aim would be to map waves created less than a billionth of a second after the Big Bang.
The niobium detector, worth $3 million and designed and made by his university, was twice as sensitive as the overseas devices, made from aluminium.
"It is a leapfrog in technology," Associate Professor Blair said. "The vibration we are measuring is as small, compared with an atom, as an atom is to a human being." However, the amount of energy believed to be carried by gravity waves is enormous.
"If you could see gravity waves, you would be blinded. They would be like flashes in the sky ... like a camera flash going off in your face."
He said it was impossible to predict what gravity wave astronomy might find.
© 1994 Sydney Morning Herald