 Notice that, as represented in  Figure 4, the matter of the collapsing  star eventually disappears into the black hole singularity. All the  details of the matter are then completely lost; all that is left is  the geometrical properties of the black hole. Astonishingly, those  properties can be identified with a small, fixed set of physical  quantities. Indeed, the remarkable No-Hair Theorems (Israel 1967,  1968; Carter 1971, 1973, 1997 [Other Internet Resources]; Robinson  1975; Mazur 1982; Heusler 1996; Chruściel et al. 2012)  make rigorous the idea that a black hole in equilibrium is entirely  characterized by just three numbers, viz., its mass, its  angular momentum, and its electric  charge.[9] This  has the remarkable consequence that no matter what the particulars  may be of any body that collapses to form a black hole—it may  be as intricate, complicated and Rococo as one likes, composed of the  most exotic materials—the final result after the system has  settled down to equilibrium will be identical in every respect to a  black hole that formed from the collapse of any other body  having the same total mass, angular momentum and electric charge  (Carter 1997 [Other Internet Resources]). Because of this extremity  of simplicity, Chandrasekhar (1983, Prologue,  p. xxiii) called black  holes “the most perfect macroscopic objects … in the  universe.” (The fact that their physical state is entirely  characterized by only three numbers plays an important role in the  ascription of thermodynamical properties to black holes, discussed in  5.2  below.) 