I've always found entropy a hard concept to grasp. Some time I read something that seems to make it more clear, then another time I read something else which completely disturbs my understanding of the idea. My current problem with entropy is the violation of the the conservation laws. And the fact that there exist actually irreversible processes. I read this wiki article that states that "During [state] transformation, there will be a certain amount of heat energy loss or dissipation due to intermolecular friction and collisions; energy that will not be recoverable if the process is reversed." But that would mean energy loss and if taken on scale of the whole universe it means that energy is destroyed... Explain please.