WASHINGTON, Nov. 5 (UPI) -- The substance known as dark matter seems to create ghost galaxies that mirror the ones we can see, astrophysicists said Wednesday.
Dark matter, a mysterious substance discovered about 30 years ago, comprises at least 25 times more mass than all the stars, planets, gas, dust and other material in the visible universe. It is the reason, scientists say, stars in galaxies and galaxies in clusters are held together by gravity and do not fly apart.
Chung-Pei Ma, an associate professor of astronomy at the University of California-Berkeley, and Edmund Bertschinger of the Massachusetts Institute of Technology, said new data prove dark matter is not a uniform mist but, rather, forms clumps that resemble the galaxies and clusters it seems to inhabit. The findings should provide scientists with a new way to calculate the evolution of dark matter and reconcile it with the observable universe, the pair said.
"Our galaxy, the Milky Way, has about a dozen satellites," Ma said. But in computer simulations, dark matter forms a "dynamic, lively environment in which thousands of smaller satellites of dark matter clumps are swarming around a big parent dark matter halo, constantly interacting and disturbing each other."
