Black Hole Entropy and Planckian Discreteness

Abstract

A brief overview of the discovery that macroscopic black holes are thermodynamical systems is presented. They satisfy the laws of thermodynamics and are associated with a temperature and an entropy equal to one quarter of their horizon area in Planck units. They emit black body radiation and slowly evaporate as a consequence of Heisenberg's uncertainty principle. The problem of understanding the microscopic source of their large entropy, as well as the nature of their final fate after evaporation, are discussed from the perspective of approaches to quantum gravity that predict discreteness at the Planck scale. We review encouraging first steps in computing black hole entropy and briefly discuss their implications for the black hole information puzzle.