Based on the OBD wiki: Want to find out how much energy it takes to blow up a planet? This is the way to do it. Gravitational Binding Energy is defined as the amount of energy it would take to scatter the mass of a gravitationally bound body to the point that its own gravity will not pull it back together again. There are precise calculations for this via integration, but a good approximation can be achieved with the following formula: File:Gravitational Binding Energy.jpg Where U = GBE, M = the mass of the body in question, r = its radius, and G = the gravitational constant.