For the first time astronomers have observed sign of dark matter interacting with a force other than gravity.

Dark matter makes up most of the universe, it is 85 percent of the universe mass, but constitutes of dark matter are still unknown.

Scientists have made the discovery when they were viewing the simultaneous collisions of four distant galaxies at the center of the galaxy cluster which is 1.3 billion light years away from Earth.

Scientists at the Durham University, UK viewed the galaxies from the Hubble Space Telescope and the European Southern Observatory’s Very Large Telescope.

Scientist found that one dark matter clump is lagging behind the galaxy it surrounds. They said that the dark matter is lagging behind its galaxy by 5,000 light years, and it would take 90 million years to travel by the NASA’s voyager spacecraft.

The dark matter lags behind the galaxy, if it interacts very slightly with the forces other than gravity.

Computer simulations show that extra friction from collision will cause the dark matter to slow down or even lag behind.

It is believed that galaxies exist in the clumps of dark matter called dark, because it is thought to interact with gravity and making it invisible.

If there was no dark matter then the galaxies like the milky way would fling themselves apart as they spin, it is the gravity of the dark matter which is holding on to it.

Dark matter clumps can be seen by gravitational lensing, where the dark matter bends the light from the distant galaxies because of its gravitational force.

The new discovery rules out the standard theory of Cold Dark Matter which theorizes that the dark matter will only interact with 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. Dark matter may not be completely ‘dark’ after all,” said Dr Richard Massey, Royal Society Research Fellow, in Durham University’s Institute for Computational Cosmology, lead author of the study.

More investigation is needed to find the other effects which can bring the lag in the dark matter.

“Our observation suggests that dark matter might be able to interact with more forces than just gravity. The parallel Universe going on around us has just got interesting. The dark sector could contain rich physics and potentially complex behavior,” said, team professor Liliya Williams, of the University of Minnesota.

The new maps show that the large portion of the sky is filled with dark matter. It also shows that there is large amount of dark matter in some places and it is entirely absent in some places.

The galaxies are present where there is high concentration dark matter and where there is less dark matter the galaxies are also very less.

The map is produced from the data taken by the Dark Energy Survey. These maps are unveiled at the American Physical Society.

The new map aggress with the current theories which states that where is dark matter there will be galaxies as the gravitational pull of the dark matter will pull the galaxies towards itself.

The universe has five times more dark matter than the matter which can be seen, and the gravitational pull by the dark matter will influence how the galaxies are formed and evolved.

The study focuses on the smaller area of the sky.

The maps are highest resolution maps of this kind over such a large area which is 150 degrees square on the sky.

The maps point that even though the dark matter and the matter which can be seen are different but dark matter has strong pull on regular matter and determines how it is distributed in the universe.

Maps when zoomed will show how dark matter envelops galaxies and how they evolve together.

The data was taken from the Dark Energy Camera which is 750 megapixels.

The main aim of the Dark Energy Survey is to understand how dark energy is causing the universe to expand faster and faster.

Dark matter is invisible because it does not emit, radiate or block light.

Dark Energy Camera used the gravitational lensing phenomenon to develop those maps. Gravitational lensing is how the dark matter’s gravitational pull bends light from distant galaxies.