What do we really know when we are looking at the stars? It is like reading a detective story following Grégoire Eloy tracking what's going on in the corridors of astrophysics. It is as unpredictable as the scientists’ research on how it all began. No clues or evidences are presented. It is a matter of thesis, mathematics and beliefs. A Black Matter is a publication of images produced in 2010 in French astrophysics laboratories (Project “Ether”), as a result of an assignment by f93, a scientific cultural center based in Montreuil, France.