'Dark matter' not as dark as first thought: Scientists find it interacts with forces other than just gravity | Steve Connor

Hubble telescope enables first view of the cosmic entity "interacting with itself."

April 15, 2015 (Independent.co.uk) -- Dark matter may not be so dark after all, after scientists witnessed the mysterious cosmic entity interacting with the universe around it an entirely new way.

Despite accounting for an estimated 85 per cent of matter in the Universe, dark matter has never been seen directly by any scientific instruments.  Its existence has only been inferred by its gravitational effects.

But astronomers have now for the first time witnessed dark matter apparently “slowing down” after interaction with other dark matter - suggesting it is capable of engaging with a force other than gravity.

“We used to think that dark matter sits around, minding its own business. But if it slowed down during this collision, this could be the first dynamical evidence that dark matter notices the world around it,” said Richard Massey of Durham University. who led the research.

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