Birkhoff’s theorem is similar to a set of theorems called no-hair theorems describing black holes. The most general no-hair theorem states that a black hole is completely characterized by its mass, ch...Birkhoff’s theorem is similar to a set of theorems called no-hair theorems describing black holes. The most general no-hair theorem states that a black hole is completely characterized by its mass, charge, and angular momentum. Other than these three numbers, nobody on the outside can recover any information that was possessed by the matter and energy that were sucked into the black hole.
