And it's not the space between W's ears.
Analysis of Galactic Collision Said to Reveal Mysterious Substance
By Marc Kaufman
Washington Post Staff Writer
Tuesday, August 22, 2006; Page A01
For decades, many scientists have theorized that the universe is made up of nearly undetectable mysterious substances called dark matter and dark energy. But until yesterday there was no proof that the subatomic matter actually exists.
After studying data from a long-ago collision of two giant clusters of galaxies, researchers now say they are certain dark matter does exist and plays a central role in creating and defining gravity throughout the universe.
...
The breakthrough came using data from NASA's orbiting Chandra X-Ray Observatory and involved information from what researchers called the most massive release of detected energy in the universe since the big bang.
Scientists said that the "bullet cluster," formed by a collision between an enormous cluster of galaxies more than 3 billion light-years away and a smaller galaxy cluster, demonstrated the existence of dark matter. In effect, the collision stripped the dark matter away from visible matter. Once stripped, dark matter was clearly identified by the strong gravitational pull that it exerted.
http://www.washingtonpost.com/wp-dyn/content/article/2006/08/21/AR2006082101139.html_____________________________
Any physicists in da house? Does this observation really damage the competing theory that gravity simply works differently over vast scales?