Authors: Steven S. Gubser & Frans Pretorius
Although Einstein understood that black holes were mathematical solutions to his equations, he never accepted their physical reality — a viewpoint many shared.Â
This all changed in the 1960s and 1970s, when a deeper conceptual understanding of black holes developed just as new observations revealed the existence of quasars and X-ray binary star systems, whose mysterious properties could be explained by the presence of black holes.
