I've been reading about the possible ends to the universe and I came across the "big freeze". http://en.wikipedia.org/wiki/Big_Freeze In this scenario, all the energy in the Universe goes out and the Universe is cold and desolate with no stars. But the law of conservation of energy states that energy cannot be destroyed. Where did all this energy go then? It's like when I punch something imaginary in mid air. What happens to the energy momentum in my fist after I am done punching? Does it vibrate the air molecules around me on such a small level into infinity? I see energy disappear around me all the time, such as when a light bulb runs out. What happens to the photons that the light bulb was giving off the entire time before it burnt out? Any help would be appreciated. Thanks! Edit: How can electrons go through houses and what not. I was wondering about radio waves and how they're just electrons moving out of the broadcasting location. Do these electrons also continue forever into space? And how do they have enough energy to go on forever?? More importantly, can these radio wave electrons get bonded to something in some sort of electric-chemical reaction?