3-D map charts details of dark matter

An international team of astronomers has produced the first three-dimensional map of dark matter, the invisible scaffolding thought to hold the universe together.

The new map provides the best evidence yet that normal matter, including all stars and galaxies, collect within the densest concentrations of dark matter, which is made up of tiny particles invisible to detection.

But while the particles are invisible, the gravitational effect of large concentrations of dark matter allowed researchers to map its whereabouts.

Dark matter accounts for most of the mass of the universe and is "the scaffolding inside of which stars and galaxies have been assembled over billions of years," said Richard Massey, an astronomer at the California Institute of Technology who led in the map's creation.

The map was unveiled Sunday at the 209th meeting of the American Astronomical Society and published online in the journal Nature.

The researchers used data from five powerful space telescopes, including the Hubble, to construct a map of a section of the universe, looking from recent times as far back as 6.5 billion years.

The map was constructed by measuring the shapes of galaxies. Light from these galaxies deflected slightly as it passed through dark matter's gravity, providing subtle distortions that gave clues to the dark matter's location.

The study found normal matter, largely in the form of galaxies, tends to concentrate or clump around the heaviest regions of dark matter.

Dark matter was first proposedin 1933 as atheory to help explain the movement and formation of galaxies. But direct detection of dark matter has onlybeen reported in the past year by researchersanalyzing the Bullet Cluster of galaxies.