Giant machines for giant questions

Australian Institute of Physics Congress 2022, Media releases
Square Kilometre Array sites in South Africa and Australia. Credit: SKA Observatory. 
  • The biggest radio telescope
  • The dark side of the universe – could Australia host a gravitational wave detector?
  • Too wet for next generation telescopes

Australian researchers are in pole position to solve some of the Universe’s greatest mysteries by participating in three massive global projects.

Stories from the Australian Institute of Physics Congress in Adelaide. 

The biggest radio telescope

Last week, construction started in Western Australia of the world’s largest radio telescope.

This will be one of humanity’s biggest-ever scientific endeavours. It is the culmination of 30 years of planning and design, and the first time Australia has hosted a mega-science project on behalf of the international community. 

Sixteen countries are partnering to build the SKA in Australia and Africa, with a total investment of about $3 billion AUD (about €2 billion).

The Australian component, SKA-Low, will consist of 131,000 antennas spread across 74km of Wajarri Yamaji country in Western Australia. It will partner with SKA-Mid, under development in Africa.

“This is an incredibly exciting time for radio astronomers in Australia and around the world,” says Dr Sarah Pearce, Director of the SKA-Low Telescope.

“After 30 years of planning, we are about to start on-site construction of two of the world’s largest telescopes, one in Australia and one in South Africa. This will define the next decades of radio astronomy as we push the boundaries of what we know about the Universe, right back to the cosmic dawn when the first stars and galaxies were born,” she says.

More about SKA

The dark side of the universe

“The Nobel-winning discovery of a gravitational wave in 2015 enabled a new kind of astronomy, exploring the dark side of the universe,” says Caltech experimental physicist Rana Adhikari.

Three Gravitational Wave Observatories, in the USA, Italy, and Japan, have underpinned the discoveries to date. Over one hundred waves have been detected, revealing massive collisions between black holes and stars.

Australian researchers have played an important role: developing sensitive detectors and analysing the results, through OzGrav, the ARC Centre of Excellence for Gravitational Wave Discovery, which has just received a further seven years of support from the Australian government.

“The next series of upgrades will increase our understanding of highly-warped spacetime, nuclear astrophysics, and cosmology. But, to reach those astrophysical targets, the measurements will have to be improved through quantum metrology, advances in thin film materials, and AI-driven feedback controls,” says Rana.

Today’s detectors are L shaped with the arms up to 4 km long. A suite of three new detectors is being discussed internationally, says OzGrav Deputy Director Professor David McClelland. Each would be much bigger than current detectors with arms up to 40km long. Australia would be perfectly placed to host one of these detectors. “Our Southern Hemisphere location will enable better triangulation of gravitational events. And our continent’s stable geology will reduce background interference,” he says.

More about OzGrav

Australia is too wet for the biggest telescopes

While the world is turning to Australia for the best locations for radio astronomy and gravitational waves, our continent is, surprisingly, too flat and wet for the biggest optical telescopes.

So, the optical astronomers are calling on Australia to join ESO, the European Southern Observatory, which operates a suite of telescopes in the Atacama Desert in Chile. It’s the driest place in the world, outside of the polar regions. The Extremely Large Telescope, currently under construction, will be fifteen times sharper than Hubble. Its main mirror will be thirty-nine metres in diameter. Membership will give Australia access to the telescopes, and to contracts to develop new technologies such as the optical microcombs reported yesterday.

Read more about the ESO and Australia