| Map of the universe years in the making|
|After 10 years of surveying the night sky, astronomers based in Australia have completed the most accurate view of our galactic neighbourhood.|
Australian, British and American astronomers at the Anglo Australian Observatory in Coonabarabran, New South Wales, meticulously charted hundreds of thousands of galaxies in our region of the universe.
Dr Heath Jones from the Anglo Australian Observatory says the map shows where galaxies are, in respect to each other, and to our own.
"Because of course we are looking into space, space is three dimensional and so really to look at this or we look at this map in a computer, we have to fly through the space between the galaxies, so we have to think of it as three dimensional space rather than a 2D roadmap," says Jones speaking to The World Today.
Previously much astronomical energy was spent trying to find the most far out objects in the universe.
In this project, astronomers looked a little closer home.
Jones says they looked at the nearest 100,000 galaxies or so.
"The galaxies just aren't uniform. They are scattered throughout the universe," he says.
"What we find is that they tend to clump and cluster together.
"So you'll get galaxies clustering along nice delicate filamentary chains.
"You get some galaxies that will congregate in their clusters and you will get clusters of galaxies collecting in super clusters of galaxies, so the universe that we see is really quite structured."
The clustering and intense speeds at which these galaxies are travelling in cannot be explained by the gravitational pull of ordinary visible matter.
Jones says explaining dark matter is one of the holy grails of science.
"Astronomers know that this dark matter must exist in the universe," he says.
"We can't see it with our telescopes directly, but by studying large objects like galaxies and how they move with respect to each other we can infer its existence quite accurately."
He says while it does seem weird, scientists have to figure out ways of mapping what they cannot see.
"I guess that is a lot of science. One has to infer the existence of things that are at the very limits of what we can detect and I mean dark matter is really important ingredient of the universe," says Jones.
"It seems to hold the galaxies together. It stops their constituent stars from flying off and it seems to be driving the large scale galaxy clusters and super clusters. They are the largest objects that we see in the universe."
Dr Jones says the galactic neighbourhood census also confirmed the theory that the universe will keep on expanding rather than eventually collapse under its own gravity.
"One of the things you see with this survey is the galaxies are all getting further apart from each other and that is the well known expansion of the universe," he says.
"But in particular with this survey we are able to analyse the very individual motions of the galaxies on top of that - what we call the peculiar motions of the galaxies.
"That is one of the strengths of this survey. We are able to look at many more peculiar motions of galaxies than has been done before."