US astronomers say they have found the first direct evidence for the mysterious stuff called dark matter. Dark matter – which does not emit or reflect enough light to be “seen” – is thought to make up 25% of the Universe. By contrast, the ordinary matter we can see is believed to make up no more than about 5% of our Universe. …
WHAT THE UNIVERSE IS MADE OF
What the researchers have done is, in effect, to identify the gravitational “signature” of dark matter. This signature was created by dark matter and ordinary matter being wrenched apart by the immense collision of two large galaxy clusters.
Study leader Doug Clowe, from the University of Arizona, said: “This provides the first direct proof that dark matter must exist and that it must make up the majority of the matter in the Universe.”? – bbc