spacetoday.net: Astronomers map dark matter

Posted: Mon, Jan 8, 2007, 8:09 AM ET (1309 GMT)
Dark matter 3-D map (STScI)

Astronomers announced Sunday that they have constructed the first three-dimensional map of dark matter in the universe, finding that the distribution of the msyterious matter has become more clumpy over time. Researchers used data from the Hubble Space Telescope, augmented with observations by groundbased telescopes and ESA's XMM-Newton spacecraft, to measure the shapes of a half-million galaxies, using the subtle distortions in their shapes caused by the gravitational lensing effect of intervening clusters of dark matter to map the darm matter's location and distribution. The results confirm earlier hypotheses that normal matter accumulates in the densest concentrations of dark matter, and that galaxy clusters are found where filaments of dark matter intersect. The distribution of dark matter has also become more clumpy over time as it collapses under the force of gravity. The results do not, however, provide new insight on the nature of dark matter, whose total mass is more than five times that of normal matter in the universe.