Dark Matter Proof Found, Scientists SayPublication: National Geographic News Date: August 22, 2006 View Article
A team of researchers has found the first direct proof for the existence of dark matter, the mysterious and almost invisible substance thought to make up almost a quarter of the universe.
Dark matter does not absorb or emit light. So far, astronomers have inferred its presence only indirectly by measuring the effects of its gravity.
But now, by observing a massive collision between two large clusters of galaxies, astronomers have detected what they say could only be the signature of dark matter.