The largest-ever structure of the enigmatic substance known as dark matter has been mapped by international astronomers who peered deep into the universe.

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Cosmologists have found the largest web of dark matter so far. Their find supports the idea that galaxies and clusters of galaxies are embedded in giant filamentous structures of dark matter to form a 'cosmic web'


They detected a web of matter spanning 270 million light-years, or more than 2000 times the size of the Milky Way.

"The results are a major leap forward since the presence of a cosmic dark matter web that extends over such large distances has never been observed before," says Ludovic Van Waerbeke, an assistant professor at Canada's University of British Columbia, who took part in the research.

Around a fifth of the universe is believed to consist of dark matter, spreading out in mysterious filaments, sheets and clusters.

But with present technology, it cannot be seen directly; researchers study it indirectly, through the gravitational pull it exerts on light.

The 19-member observational team drew up the map from images provided by the Canada-France-Hawaii Telescope in Hawaii.

The images were captured by the telescope's 340 megapixel digital camera, the largest available to astronomers in the world.

Their technique is based on weak gravitational lensing, a phenomenon predicted by Einstein under which light from distant galaxies is deflected by dark matter as it travels through the cosmos to us.

The work, to be published in the journal Astronomy and Astrophysics, confirms theories about the massive extent of dark-matter structures and the lensing technique, the researchers say.

"The size of the structure we measured corresponds to the limits of our current observational capacity," says Dr Martin Kilbinger of the Paris Institute of Astrophysics.

"In reality, these structures are probably even bigger."

The researchers say their results confirm what's known as the 'cold dark matter' paradigm.

This predicts that galaxies and clusters of galaxies are embedded in giant filamentous structures of dark matter to form a 'cosmic web'.