Too much from too little

Features of black holes and quasars which have been detected empirically and/or predicted theoretically are described qualitatively. Colliding shock waves have been modeled as the cause of the large fluctuations in output observed with quasars. The duration of the fluctuations, in combination with observed redshift distances of the objects, have been used to estimate the size of the emitting regions. Models of a black hole suggest that quasars are black holes converting up to 10% of their rest mass to energy, having a preferred direction of rotation, and absorbing destroyed stars as fuel.