article_snippet.sent: The first signs of dark matter interacting with a force other than gravity may have been found.
article_snippet.sent: Until now it was thought that dark matter did not interact with anything other than gravity, earning it it
article_snippet.sent: Dark matter is confusing because Dark matter interacts with nothing - including itself.
article_snippet.sent: This is despite seeming to account for 85 per cent of the universe’s mass and having an observable effect on galaxies: without dark matter, our galaxies would ‘fall apart’ as our galaxies spin.
article_snippet.sent: Aside from gravity, though, dark matter seemed to just pass through our universe without interacting with any other mass, such as humans, planets or stars.
article_snippet.sent: If physicists only take visible matter into account, physicists equations don't add up; the elements that can be observed are not sufficient to explain the rotation of objects and the existing gravitational forces.
article_snippet.sent: From this physicists deduced there must be an invisible kind of matter that does not interact with light but does, as a whole, interact by means of the gravitational force.
article_snippet.sent: The offset is important because it is only possible if dark matter interacts with itself through forces other than gravity.
article_snippet.sent: If the particles collide with each other, the friction from the collisions would cause the dark matter to slow down, and fall behind the galaxy.
article_snippet.sent: But dark matter has never before been observed interacting in any way other than through the force of gravity - making the discovery of huge interest.
article_snippet.sent: We used to think that dark matter just sits around, minding We own business, except for We gravitational pull,’ Dr Richard Massey from Durham University said.
article_snippet.sent: But if dark matter were being slowed down during this collision, dark matter could be the first evidence for rich physics in the dark sector - the hidden universe all around us.
article_snippet.sent: Dr Richard Massey from Durham University added to MailOnline: 'This is the first time we've caught dark matter in the act of doing something interesting. '
article_snippet.sent: Once the dark universe around we is allowed to interact at all, the possibilities for what it could get up to are rich and varied.'
article_snippet.sent: Although dark matter cannot be seen, its gravitational pull,’ Dr Richard Massey from Durham University could deduce its gravitational pull,’ Dr Richard Massey from Durham University location using a technique called gravitational lensing.
article_snippet.sent: Our current understanding is that all galaxies exist inside clumps of dark matter, which is how all galaxies are able to survive without flinging all galaxies apart.
article_snippet.sent: We know that dark matter exists because of the way that dark matter interacts gravitationally, helping to shape the universe, but We still know embarrassingly little about what dark matter actually is,' said team member Dr Liliya Williams of the University of Minnesota. '
article_snippet.sent: We observation suggests that dark matter might interact with forces other than gravity, meaning We could rule out some key theories about what dark matter might be.'
article_snippet.sent: This result follows on from recent findings from the team which observed 72 collisions between galaxy clusters and found that dark matter interacts very little with itself.
article_snippet.sent: This latest study follows research by the same team last month that found dark matter interacts with This latest study very little - but the fact that This latest study interacts at all is very exciting, said Dr Massey.
article_snippet.sent: Taken together, the two results bracket the behaviour of dark matter for the first time.
article_snippet.sent: Dr Massey Dr Massey added: 'We are finally homing in on dark matter from above and below - squeezing We knowledge from two directions.'
highlights_snippet.sent: This suggests dark matter particles can self-interact and slow down .
  
highlights_snippet.sent: It means dark matter may not be as oblivious to our universe as we thought .