Thermodynamics is statistical. It don't exactly apply to individual particle pairs interacting. It apply to the larger system they're a part of. Also: http://w

Thermodynamics is statistical. It don't exactly apply to individual particle pairs interacting. It apply to the larger system they're a part of. Also: http://www.livescience.com/18580-perpetual-motion-time-crystals.html http://www.livescience.com/18580-perpetual-motion-time-cryst... The thing is that you can have essentially static periodic systems, where in entropy do not go down but simply don't increase. Overall in the universe entropy will however increase on average.