PARIS (AFP) -- An international team of astronomers peering into the deep Universe said on Thursday they had mapped the biggest-ever structure of the enigmatic substance known as dark matter.

They detected a web of matter spanning 270 million light years, or more than 2,000 times the size of our own galaxy, the Milky Way, they said.
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. Its existence is perceived indirectly, through the gravitational pull it exerts on light.
Observational team
The 19-member observational team drew up the map from images provided by the Canada-France-Hawaii telescope located in Hawaii.
Their technique is based on 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, published in the U.S. journal Astronomy and Astrophysics, confirms theories about the massive extent of dark-matter structures and the lensing technique, they say.
""The size of the structure we measured corresponds to the limits of our current observational capacity,"" Martin Kilbinger of the Paris Institute of Astrophysics told AFP.
""In reality, these structures are probably even bigger.""