The Horizon Energy of a Black Hole

We investigate the energy distribution of a black hole in various spacetimes as reckoned by a distant observer using the quasi-local energy approach. In each case the horizon mass of a black hole: neutral, charged or rotating, is found to be twice the irreducible mass observed at infinity. This is known as the Horizon Mass Theorem. As a consequence, the electrostatic energy and the rotational energy of a general black hole are all external quantities. Matter carrying charges and spins could only lie outside the horizon. This result could resolve several long-standing paradoxes related to known black hole properties; such as why entropy is proportional to area and not to volume, the information loss problem, the firewall problem, the internal structure and the thin shell model of a black hole.