The hunt for dark matter: Sydney joins ARC Centre of Excellence

20 September 2019
Professor Celine Boehm welcomes $35 million funding for national research centre to answer one of physics great open questions.
Professor Céline Boehm, Head of the School of Physics. Photo: Jayne Ion. Main image above: MPA Garching

Professor Céline Boehm, Head of the School of Physics. Photo: Jayne Ion. Main image above: MPA Garching

Astronomy – and physics itself – stand on the brink of a revolution.

Despite Einstein’s theory of general relativity proving itself an astoundingly precise predictor of physical events, we also know something is not quite right.

The ordinary stuff of matter we see every day – puppies, mountains, smoke, insects, algae, oceans, planets, butterflies, the Moon and the Sun and our friends – only makes up 5 percent of the energy of the universe. It is the stuff of stars.

Yet from our observations we know there is much more; dark matter and dark energy, which make up the rest. We just don’t know what they are.

“There is a revolution to be had,” said Professor Céline Boehm, Head of the School of Physics at the University of Sydney. “Our laws are not complete and who knows, maybe our interpretation of the laws of physics is completely wrong.”

Professor Boehm last month was named a Chief Investigator in the new $35 million Australian Research Council Centre of Excellence for Dark Matter Particle Physics.

Her job is to help explain what it is we call dark matter, which we estimate makes up 25 percent of the entire energy of the universe.

Our observations of rotating galaxies tell us that our understanding of the cosmos is incomplete. If the observable matter was all there was, then galaxies would fall apart – and might not even form in the first place.

The outer reaches of these agglomerations of stars should rotate slower than their centres and the structures should fall apart.

But they don’t. They hold together.

“We still don’t know how galaxies rotate the way they do,” Professor Boehm said. “What we do know is that there is something weird we need to understand. It means our laws of physics are incomplete.”

Unlocking the secrets of physics

Professor Boehm will join researchers across Australia to tackle one of the greatest open questions in science today: what is dark matter?

“Unlocking this secret has the potential to completely transform modern physics,” Professor Boehm said.

“Einstein’s revolution in gravity opened up the 20th century to completely new understanding and to technologies that he couldn’t predict. General relativity changed everything. Without it there would be no comprehension of black holes, no GPS, no satellite communication and no modern electronics.

“Discovering the secret to dark matter will be just as transformational.”

The ARC Centre for Dark Matter Particle Physics will be based at the University of Melbourne, with research nodes at Sydney, the University of Western Australia, Swinburne University, the Australian National University and ANSTO, Australia’s Nuclear Science and Technology Organisation.

Professor Elisabetta Barberio.

Professor Elisabetta Barberio.

The director of the centre is Professor Elisabetta Barberio, who is also the founding director of the Stawell Underground Physics Laboratory, which will be an important site in the centre’s hunt for dark matter.

The ARC centre will establish a detector in the Stawell laboratory designed to interact with elusive dark matter a kilometre underground in an old gold mine.

“The detector needs to be isolated from neutrons,” Professor Boehm said.

Professor Barberio said the ARC Centre will allow scientists to conduct vital research at the underground facility and provide a much-needed boost for Australian scientists in the search for dark matter.  

“Our strong and diverse team of physicists from particle and nuclear physics, quantum measurement and astrophysics will conduct experiments using new cutting-edge technologies,” she said.

The Stawell Underground Physics Laboratory will be a national facility and the southern hemisphere's epicentre for dark matter research.

“It will provide a dynamic environment for advances in ultra-sensitive detectors, ultra-low radiation techniques, spin-off technology translation and highly trained graduates ready to lead innovation in Australian industry,” Professor Barbeiro said.

Professor Boehm will lead the Sydney node and will hire an associate professor and postdoctoral researcher to work with her on the research.

“If – or when – they get a signal at Stawell, there will be a lot of work to do. As a theoretician it will be my job to explain what has happened. I have the expertise to build the models that can explain the signal and we can hopefully use this to explain what we see in the cosmos.”

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