Cosmic Stocktake Reveals What's Left of Big Bang

Aug 18, 2006

The Universe has guzzled its way through about 20 per cent of its normal matter, or original fuel reserves, according to findings from a survey of the nearby Universe by an international team of astronomers involving researchers at The Australian National University.

The survey, to be released at the General Assembly of the International Astronomical Union in Prague today, revealed that about 20 per cent of the normal matter or fuel that was produced by the Big Bang 14 billion years ago is now in stars, a further 0.1 per cent lies in dust expelled from massive stars (and from which solid structures like the Earth and humans are made), and about 0.01 per cent is in super-massive black holes.

The survey data, which forms a 21st century database called the Millennium Galaxy Catalogue, was gathered from over 100 nights of telescope time in Australia, the Canary Islands and Chile, and contains over ten thousand giant galaxies, each of these containing 10 million to 10 billion stars.

According to the survey leader Dr Simon Driver of St Andrews University, Scotland, the remaining material is almost completely in gaseous form lying both within and between the galaxies, forming a reservoir from which future generations of stars may develop.

“I guess the simplest prognosis is that the Universe will be able to form stars for a further 70 billion years or so after which it will start to go dark," said Dr Driver. “However, unlike our stewardship of the Earth the Universe is definitely tightening its belt with a steady decline in the rate at which new stars are forming."

Dr Alister Graham, an astronomer at The Australian National University who worked on the survey, said that the team of researchers were able determine how much of matter is in the stars through a ‘cosmic stocktake.’

“We needed to measure the stellar mass within a representative volume of the local Universe. This required accurate and complete distance information for all the galaxies of stars that we imaged. This is where the Australian telescopes played a key role," Dr Graham said.

One of the unique aspects of this program was the careful separation of a galaxy's stars into its central bulge component and surrounding disc-like structure. This allowed the researchers to determine that, on average, roughly half of the stars in galaxies reside in discs and the other half in bulges.

“Measuring the concentration of stars in each galaxy's bulge is what enabled us to determine their central super-massive black hole masses," said Dr Graham. “Some of these are up to one million billion times more massive than the Earth. Once we had these masses it was a simple task of summing them up to determine how much of the Universe's matter is locked away in black holes at the centres of galaxies."

Dr Graham said next-generation telescopes such as the Giant Magellan Telescope, currently in production, will enable astronomers to directly measure black hole masses in galaxies ten times further away and thus ten times further back in time. “In effect, we’ll soon be able to observe how galaxies and their black holes evolved into what we see around us today."

Other members of the research team include Paul Allen and Ewan Cameron of The Australian National University, Jochen Liske of the European Southern Observatory, and Roberto De Propris of the Cerro Tololo Inter-American Observatory.

The Millennium Galaxy Catalogue consists of data from the Anglo-Australian Telescope, The Australian National University's 2.3 m telescope at Siding Spring Observatory, the Isaac Newton Telescope and the Telescopio Nazionale Galileo at the Spanish Observatorio del Roque de Los Muchachos of the Instituto de Astrofisica de Canarias, and also from the Gemini and ESO New Technology Telescopes in Chile.

Source: Australian National University

Explore further: How can dark matter cause chaos on Earth every 30 million years?

Related Stories

Far from home: Wayward cluster is both tiny and distant

Mar 03, 2015

Like the lost little puppy that wanders too far from home, astronomers have found an unusually small and distant group of stars that seems oddly out of place. The cluster, made of only a handful of stars, ...

Time for the world's largest radio telescope

Feb 13, 2015

On a recent trip to Australia, the National Physical Laboratory (NPL) visited one of the two sites of the Square Kilometre Array (SKA) - a global science and engineering project to build the worlds largest ...

Recommended for you

Dusty substructure in a galaxy far far away

6 hours ago

Scientists at the Max Planck Institute for Astrophysics (MPA) have combined high-resolution images from the ALMA telescopes with a new scheme for undoing the distorting effects of a powerful gravitational ...

ALMA disentangles complex birth of giant stars

6 hours ago

A research group led by Aya Higuchi, a researcher at Ibaraki University, conducted observations of the massive-star forming region IRAS 16547-4247 with the Atacama Large Millimeter/submillimeter Array (ALMA). ...

Image: The tumultuous heart of the Large Magellanic Cloud

Mar 31, 2015

A scene of jagged fiery peaks, turbulent magma-like clouds and fiercely hot bursts of bright light. Although this may be reminiscent of a raging fire or the heart of a volcano, it actually shows a cold cosmic ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.