An international research team conducted a giant survey, called the 2dF Galaxy Redshift Survey, to create the world's largest 'catalogue' of the galaxies, currently numbering 210,000.
"This is by far the biggest such map," said Dr Matthew Colless from the Australian National University, a co-leader of the survey team.
"This is the first time we have looked at a big enough volume of the universe to say we have a fair sample. Now we have a fair idea of what all the other galaxies look like."
Galaxies are pulled around by the gravity of the Dark Matter forming into large-scale 'sheets' and 'filaments', Dr Colless explained.
"It's only because of the Dark Matter that galaxies hold together."
For example, our galaxy is rotating so quickly that if there was only the visible matter it would pull apart by centrifugal force.
"The Dark Matter around it holds our star in its orbit in the galaxy."
The galaxy map compiled by the researchers show that the distribution of sheets and filaments is just what is expected if the galaxies and Dark Matter cluster in the same way.
Until now astronomers thought that the distribution of Dark Matter in the Universe was different to that of galaxies.
"That opened up a whole a Pandora's box of difficult and hard-to-explain scenarios for how galaxies formed," Dr Colless said.
"The new thing we have been able to say with this work is the Dark Matter is scattered around the Universe in exactly the same way as the visible matter."
"This finding that things are relatively simple makes things much easier."
The survey was made possible by the Anglo-Australian Telescope's 2dF (two-degree field) instrument, which can find the three-dimensional positions of 400 galaxies simultaneously.
The 2dF is currently unique in the world because it covers an area of sky equivalent to the diameter of four full moons.
"That's one field," said Dr Colless. "We [observe] a thousand times and that gets us five per cent of the sky about 2000 square degrees."
The astronomers map the position of galaxies by measuring a phenomenon called redshift. As a galaxy expands, the light moving away from it stretches, making the wavelengths longer so that the light moves from the visible to the infra-red spectrum.
"The amount of that shift is proportional to how far the galaxy is away from us," said Dr Colless. The 'redder' an object is, the further away it must be. "By measuring the colour of a galaxy you can measure its distance."
|Computer simulation of Dark Matter (grey) and galaxies (coloured circles). Red box indicates formation of a rich cluster of galaxies. Note how the galaxies appear to trace out the major features in the Dark Matter. (Pic: Benson, Baugh, Cole, Frenk and Lacey, Monthly Notices of the Royal Astronomical Society, vol 311, 2000)|
"Because there is seven times as much Dark Matter as ordinary matter, it is the Dark Matter that really does, well, matter," explained Dr Colless.
The finding should help astronomers work out how galaxies and stars formed.
"This finding does two things. It allows us to get a more accurate measurement of the total amount of matter in the Universe," Dr Colless said. "The second thing is it narrows down which theories work and which don't."
The paper was published online this week on the preprint service astro-ph.
The survey began in 1997 after four years after pre-planning, and the team has had 15 papers released this year.
"It's really just now showing the fruits of our long labours on the project," Dr Colless said.