> which states that entropy, or a loss of the energy available to do work, must rise over time.[2] Stars will eventually exhaust their supply of hydrogen fuel a

> which states that entropy, or a loss of the energy available to do work, must rise over time.[2] Stars will eventually exhaust their supply of hydrogen fuel and burn out. Since entropy is a statistical quantity, the second law of thermodynamics is a statistical statement. And because modern physics essentially deals with Hamiltonian systems, it can be proven that a time exists when entropy goes down again. The intuitive proof is really nice. Since energy is conserved, one can imagine the global state (position, momentum) as position in a park covered in snow. So someone walking through it will eventually walk over his own footsteps. Not precisely but it's arbitrarily close, the longer one waits. https://en.wikipedia.org/wiki/Poincaré_recurrence_theorem https://en.wikipedia.org/wiki/Poincaré_recurrence_theorem I really like that theorem