Dark matter Explained

In 1929 , Edwin Hubble discovered while looking in the sky that the stars are moving very fast . They are attracted by some hidden energy , which are called Dark Matter . Though dark matter is invisible , it is coined as dark . Simply put , dark matter is unaccounted for , yet understood to be hidden stuff of the universe , the presence of which can only be inferred by studying gravitational effects . It has no observable celestial bodies . 

Dark matter is not termed as blackhole ; it is called dark because it cannot be seen and pulls everything inwards to it . Dark matter is a form of matter thought to account for approximately 85% of the matter in the universe and about a quarter of its total mass–energy density or about 2.241×10⁻²⁷ kg/m³ .

 

Source : 1001 Ideas , Space.com