Hoping to catch a new wave
	MSc student Karl Baigent, Prof John Sandeman and PhD student Daniel Shaddock with some of the equipment which would be used in the gravity-wave detector.
By Damon Shorter Einstein predicted them in 1916. Two US astronomers earned a Nobel Prize in 1993 for proving they exist. All that is needed now is for someone to actually find them. Gravity waves are the latest in a long list of holy grails for physicists around the world - unimaginably tiny wobbles in the fabric of space-time which, if discovered, would give scientists a way to "listen" to the noises of the universe in the same way that astronomers now use light and radio waves to "see" into the depths of space. ANU Emeritus Professor John Sandeman, from the Department of Physics, heads the Australian Consortium for Gravitational Wave Astronomy, a delegation seeking funding to have a state-of-the-art gravity-wave detector built at a site near Perth in Western Australia. Known as the Australian International Gravitational Observatory (AIGO), the proposed device will, in its initial phase, consist of a building with two 500-metre arms positioned in an L-shape. A powerful and unprecedentedly accurate laser beam will be bounced back and forth in a vacuum between mirrors in these arms, creating a precise optical instrument known as an interferometer. The machine will be sensitive enough to "hear" the individual motion of atoms in the mirrors and, it is hoped, detect the unimaginably tiny distortions in distance between the mirrors that signal the passing of a gravity wave. Daniel Shaddock, a PhD student helping design the optics for the instrument, said discovering gravity waves will open a new window on the universe and generate many spin-off technologies as by-products of the research. Anti-gravity boots are not forshadowed but physicists from the University of Adelaide working on the AIGO project are designing lasers powered by the equivalent of a car battery that can slice through a brick. Mr Shaddock said other important technical breakthroughs necessitated by the construction the observatory would flow on to industry. Space is thought to be full of gravity wave "sounds" - loud drum beats from the formation of black holes, tweets like bird-calls from neutron-stars coalescing, pure tones from rotating neutron stars and continuous murmurs from the Big Bang itself. But the noises of the universe have gone unheard, Prof Sandeman said, because gravity waves "are so bloody small". The largest waves the team hopes to find will show up as blips less than one billionth of a billionth of a metre in size. Once built, the Australian observatory will form a crucial southern hemisphere component of an international array of detectors working together to try and sort out the tell-tale gravity waves signals from other background seismic rumbles. A prototype machine with 40-metre arms has already been built in the US and full-sized observatories are under construction in Europe, the US and Japan. Prof Sandeman said the Australian device could be built for around $10 million - a cost he says is easily justified. "The 10km stretch of road they've just built from Sutton to Canberra cost about $70 million," he said. "So for the cost of about one kilometre of road we can make one of the most sensitive instruments ever built."