Galactic Cluster Collision Divides Ordinary Matter from Dark Matter

Almost six billion years ago, two of the largest gravitational structures in the universe slammed into each other with velocities in the millions of miles per hour. Galactic clusters are collections of galaxies (sometimes thousands of them) that seem to hang together in violation of the known laws of physics. Not only… »8/29/08 11:00am8/29/08 11:00am