In this article we are going to discuss one of the biggest embarrassments for astrophysics: The fact that we do not really know what most of the universe is made of. Astronomers believe that there are about five times more of some untraceable dark matter in the universe than there is normal matter. Dark matter is to cosmos as air is to humankind: ubiquitous, necessary, unseen but felt.

In previous article we tried to understand more about neutron stars, but the subject of this article is about even more massive and even denser stellar objects: Black holes. Two years ago, the first ever picture of a black holes was released, which engaged the whole world.