AS FEATURED IN THE AGE
Local scientists have begun the groundwork for a campaign to potentially make Australia the site of one of the biggest science instruments ever built.
Nicknamed Cosmic Explorer South, the 40-kilometre long, $1.5 billion instrument is designed to detect ripples in space time throughout the entire universe.
The global astronomy community is drawing up plans for three such detectors based around the world, which are slated for construction in the 2030s.
Australia is the perfect place to build one, local scientists believe.
"There is no doubt in my mind that Australia is the best location for this," says Professor Matthew Bailes, who directs the Australian Research Council Centre of Excellence for Gravitational Wave Discovery and is spearheading Australia’s bid, along with Professor David McClelland at the Australian National University.
"We don’t have a preferred site yet. But we have been placing little L-shaped things on maps to see where they might fit."
Explorer South is a next-generation gravitational wave detector. It would be able to sense gravitational waves from the very first stars born in the universe.
It will consist of two, 40-kilometre long vacuum tubes placed at right angles, like a big L.
Down the middle scientists would fire a "James Bond-strength" laser, says Professor Bailes.
A device of that size would dwarf another piece of big science, the Large Hadron Collider, which is 27 kilometres in diameter and straddles the Franco-Swiss border.
A white paper for the gravitational wave project was quietly submitted to the Australian Academy of Science earlier this year, proposing an initial $5 million investment to begin exploratory work.
The technique has already been proved by the American-based LIGO, which first detected a gravitational wave in 2015, using two arms, each four kilometres long.
How it works
When black holes collide, so much energy is released it causes ripples in space time.
These ripples spread out through the universe, like ripples on a pond. When they reach Earth, they slightly stretch and then shrink our space-time (yes, you are being very slightly stretched and shrunk too). As a gravitational wave passes through Earth, LIGO's arms stretch a little; a laser beam shone down the middle of the arms allows scientists to detect that tiny change in distance.
Scientists now want to go further – using those ripples to get information about the formation of the universe. To do that, they need to go bigger.
International astronomers are now planning the next generation of gravitational wave detectors. One wave detector, the Einstein Telescope, is planned in Europe. Another, Cosmic Explorer, is being planned for America.
A third detector in the southern hemisphere – Cosmic Explorer South – would allow scientists to triangulate the source of any waves they detected. Senior experts from the National Science Foundation, the American government’s science funding agency, are aware of Australia's interest.
Any location needs to be extremely flat and geologically stable, which makes Australia’s vast interior perfect. The arms of the detector need to be perfectly straight. But if you build something 40 kilometres long, you need to take into account the Earth’s curve.
"So you want to find a valley, where the shape of the valley is exactly compensated by the curve of the Earth," says Professor Bailes.
If you were to place it in Melbourne’s CBD, one 40 kilometre arm would stretch nearly to Healesville and the other well past Sunbury. The extreme size makes Cosmic Explorer South 100 times more powerful than LIGO, says Professor Bailes. It could measure distances down to one ten-thousandth of the width of a proton, and be sensitive enough to detect the gravity of a passing cloud.
Professor Bailes would not reveal any possible locations, because of the risk of land speculators buying them. But it would need to be near an airport or regional hub, he said. The government needs long lead times on science mega-projects, and there is a lot of due diligence to do before asking for government funding, Professor Bailes says.
If Explorer South were built here, Australia would likely have to spend about $300 million on the project, with the rest kicked in by governments around the world.