It's a big day for astrophysics and people like me who love to ponder the many questions it raises about our universe. After much speculation, scientists now have conclusive proof dark matter -- the invisible substance accounting for most of the universe's mass -- truly does exist.
Scientists found evidence of dark matter after a collision between a pair of galactic clusters that formed a "bullet" cluster over the past 100 million years. The key here is the visible mass you see highlighted in the center of the accompanying image that scientists tracked with the help of NASA's Chandra telescope, the Hubble Space telescope and various observatories that illustrates the most energetic cosmic event known to man besides the Big Bang.
Without dark matter, an invisible substance detected only by its gravity, the fast moving galaxies and hot air that make up our universe would quickly come apart, scientists said.
USA Today August 22, 2006
Cosmic Variance August 21, 2006
Chandra X-Ray Observatory August 21, 2006