There is the concept of the heat death of the universe. http://en.wikipedia.org/wiki/Heat_death_of_the_universe http://en.wikipedia.org/wiki/Heat_death_of_the

There is the concept of the heat death of the universe. http://en.wikipedia.org/wiki/Heat_death_of_the_universe http://en.wikipedia.org/wiki/Heat_death_of_the_universe Essentially, as particles expand and spread out, the universe will reach a point where there is not enough energy localized in one area to support anything. Of course this is just one theory. etc etc