Post by glactus on Sept 25, 2008 4:44:54 GMT
Just as unseen dark energy is increasing the rate of expansion of the universe, there's something else out there causing an unexpected motion in distant galaxy clusters.
Scientists believe the cause is the gravitational attraction of matter that lies beyond the observable universe, and they are calling it "Dark Flow," in the vein of two other cosmological mysteries, dark matter and dark energy.
"The clusters show a small but measurable velocity that is independent of the universe's expansion and does not change as distances increase," said lead researcher Alexander Kashlinsky at NASA's Goddard Space Flight Center in Greenbelt, Md. "The distribution of matter in the observed universe cannot account for this motion."
"We never expected to find anything like this," he said.
Using NASA's Wilkinson Microwave Anisotropy Probe's (WMAP) three-year view of the microwave background and a catalog of clusters, the astronomers detected hundreds of galaxy clusters that appear to be carried along by a mysterious cosmic flow.
The bulk cluster motions are traveling at nearly 2 million miles per hour. The clusters are heading toward a 20-degree patch of sky between the constellations of Centaurus and Vela.
The Astronomer
Glactus
Credits: Original source - NASA
This is part text only. See image, full text and all scientists involved at universetoday.com
www.universetoday.com/2008/09/23/scientists-detect-dark-flow-matter-from-beyond-the-visible-universe/
Article presenter : Nancy Atkinson