Astronomers from the National Optical Astronomy Observatory in Arizona reported on Wednesday that they have spotted a pair of massive black holes which are orbiting each other in the centre of same galaxy.

This should be the best evidence for existence of binary black hole system.

Astronomers calculated that two black holes are orbiting each other in galaxy which is about 5 billion years away from Earth.

Scientist calculated that mass of one of those two black holes is billion times bigger than mass of the Sun.

Scientists for a long time believed that there are black holes in the centre of most of galaxies in universe.

Scientist believed that when it comes to collision of two galaxies, than their black holes attract each other but now they found evidence for this theories.