Dark matter ‘interacting’ with force other than gravity

Washington: Dark matter may not be completely "dark" after all as an international team of scientists has discovered the first potential signs of dark matter interacting with a force other than gravity. The finding potentially rules out the standard theory of "Cold Dark Matter" where dark matter interacts only with gravity.

The team found that one dark matter clump appeared to be lagging behind the galaxy it surrounds.The clump was currently offset from its galaxy by 5,000 light years (50,000 million million km) - a distance that would take NASA's Voyager spacecraft 90 million years to travel. Such an offset is predicted during collisions if dark matter interacts, even very slightly, with forces other than gravity.