- Void is an astonishing medium : some Finnish scientists have been able to extract light from it, according to a survey published in the PNAS journal. Yet it seems impossible if we understand void as what remains when everything has been removed. At this point let us ask ourselves : just what does this “everything” represents ? Matter, of course, and also light. Is it enough? Perhaps we should add more precisely : void is what remains when everything we were thinking of has been removed . Le Monde Science et Techno (March 21rst 2013) Roland Lehouck (Astrophysicist at the Commissariat for atomic energy and alternative energies)