Physicist Amelia Brennan knows more than most about the stuff that holds the universe together.

She recently returned to Melbourne after a stint at CERN – the European Organisation for Nuclear Research in Geneva - where the sub-atomic Higgs boson or "God particle" was discovered in 2013.

Despite the discovery, hailed as a major scientific breakthrough, Ms Brennan said she and her CERN colleagues could still only account for 25 per cent of the matter in the universe.

But the mysteries of astrophysics are clearly part of the attraction.

"We don't know about what makes up the majority of the matter in the universe," she said.

"We should want to know. Why should we be satisfied with what we know so far?"

Ms Brennan is one of a growing number of Australians who have contributed to the groundbreaking work at CERN.

She first became interested in this particular strand of physics at high school, and after digging a little deeper she became "absolutely inspired" by the field.

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CERN is home to one of the largest and most expensive science experiments on the planet: the Large Hadron Collider, a 27-kilometre circular tunnel 800 metres below ground that reportedly cost more than $15 billion to build.

As part of her work, Ms Brennan analysed data from the ATLAS detector, which is one component of the CERN collider.

Within this seven-tonne device millions of microscopic particles are smashed together at the speed of light over several hours.

These collisions are photographed and scrutinised by an international team of scientists.

The discovery of the God particle confirmed long-held theories about the universe and why everything within it had mass and weight.

"To actually come [to CERN] and see the number of people working here on site and see the detector – it's really important," she said.

"There's a lot of Australians working on ATLAS in Australia but I do think it's important for us to come over here and see what it's all about."

Australians at the frontier of particle physics

CERN physicist Dr Richard Jacobsson hopes their work will provide more answers to fundamental questions about life and the cosmos.

"It's to see into nature, it's to see into its tiniest detail to understand it," he said.

The Large Hadron Collider is one of the largest and most expensive science experiments ever undertaken. ( CERN )

"We are asking questions about the universe."

Professor Geoff Taylor from the University of Melbourne is another Australian undertaking research at CERN.

"To be at this cutting edge there's only one facility in the world for us," Professor Taylor said.

"The only way of getting to the frontier of particle physics was to come and join the collaborations here."

Professor Taylor was part of the team that discovered the God particle.

"Without [Higgs boson], our universe wouldn't be as it is," he said.

"It would be a completely different universe."

Curiosity drives research ambitions

Despite the contributions of Mr Taylor, Ms Brennan and others at CERN, Australia is not a member nation.

At around $7 million a year, the cost of becoming one does not come cheap.

But CERN physicist Professor Emmanuel Tsesmelis believes such a move could be lucrative for Australia.

"[Australia has] contributed already to the scientific program, they've contributed to the engineering aspects and technology," Professor Tsesmelis said.

"There is an industrial base there to actually profit."

The Large Hadron Collider is currently being upgraded to double its power.

But the hunger for knowledge means physicists such as Dr Jacobsson will not be putting their feet up.

"I will never sit on a sofa, it drives me mad to be sitting down," he said.

"We are all driven by curiosity - I mean, through our lives we are curious about things and this is just the extreme interest in curiosity.

"You're really fixated and of course your family, everyone else suffers."