Paul Rincon, BBC News: Striking evidence has been found for the enigmatic “stuff” called dark matter which makes up 23% of the Universe, yet is invisible to our eyes. The results come from astronomical observations of a titanic collision between two clusters of galaxies 5.7 billion light-years away.
Astronomers detected the dark matter because it separated from the normal matter during the cosmic smash-up. The research team are to publish their findings in the Astrophysical Journal.
Dark matter is shown in blue, ordinary matter is coloured pink