The second law of thermodynamics states that entropy (a measure of disorder simply understood as energy unable to be used to do work) of an isolated system always increases. Isolated systems are those that spontaneously progress toward the state of maximum entropy of the system, also described as thermal equilibrium—no net heat flow between objects. The entropy of the universe only increases with time. One of the impacts of this law is that we need to expend energy to create order. Without the deployment of energy, all things move away from order.
