Stars and galaxies account for just 10% of the 'normal' matter (as opposed to dark matter or dark energy) of the universe. The remainder is predicted to exist as intergalactic filaments which the current study confirms accounts for the "missing mass".

Credit: NASA

Related articles

• "Warm" dark matter lights up earliest stars
• Large chunk of missing universe found
• Physicists capture image of elusive neutrinos
• Black holes are bigger than we thought
• Probe finds missing baryonic matter

SYDNEY: A 22-year-old Australian university student has solved a problem which has puzzled astrophysicists for decades, discovering part of the so-called 'missing mass' of the universe during her summer break.

Undergraduate student Amelia Fraser-McKelvie made the breakthrough during a holiday internship with a team at Monash University in Melbourne, locating the mystery material within vast structures in the intergalactic medium called filaments.

The paper has been accepted for publication in the Monthly Notices of the Royal Astronomical Society.

Ordinary mass - just missing

Monash astrophysicist Kevin Pimbblet explained that scientists had previously detected matter that was present in the early history of the universe but that could not now be located.

"There is missing mass, ordinary mass not dark mass ... It's missing to the present day," said Pimbblet.

"We don't know where it went. Now we do know where it went because that's what Amelia found."

Fraser-McKelvie, an aerospace engineering and science student, was able to confirm after a targeted X-ray search for the mystery mass that it had moved to the filaments of galaxies, which stretch across enormous expanses of space.

New technology accounts for missing matter

Pimbblet's earlier work had suggested the filaments as a possible location for the "missing" matter, thought to be low in density but high in temperature.

Pimbblet said astrophysicists had known about the 'missing' mass for the past two decades, but the technology needed to pinpoint its location had only become available in recent years.

"It was thought from a theoretical viewpoint that there should be about double the amount of matter in the local universe compared to what was observed.

"It was predicted that the majority of this missing mass should be located in large-scale cosmic structures called filaments - a bit like thick shoelaces," said Pimbblet.

He said the discovery could drive the construction of new telescopes designed to specifically study the mass.

"I cannot underscore enough what a terrific achievement this is. We will use this research as a science driver for future telescopes that are being planned, such as the Australian Square Kilometre Array Pathfinder, which is being built in outback Western Australia."

Knock on effects of pure physics

Pimbblet admitted the discovery was primarily academic, but he said previous physics research had led to the development of diverse other technologies.

"The pure research has knock-on effects to the whole society which are sometimes difficult to anticipate."

"Whenever I speak to people who have influence, politicians and so on, they sometimes ask me 'Why should I invest in physics pure research?'. And I sometimes say to them: 'Do you use a mobile phone? Some of that technology came about by black hole research'."