Black Hole Mechanics and Thermodynamics
In the 1970’s, Bekenstein realized that, assuming the second law of thermodynamics holds, a black hole must carry entropy . This follows from the fact that if we throw an object with some entropy into a black hole, the entropy of the total system may not decrease, hence the entropy of a black hole must grow when we throw an object into it. Such thought experiments can be used to derive the laws of black hole mechanics, which turn out to be profoundly connected to the laws of thermodynamics. In particular, certain parameters from black hole physics will be seen to correspond to thermodynamic quantities.