Is there a possibility that the Universe is perpetually expanding ? I think that after the initial impetus of the big bang where matter was distributed progressively, gravitation between the different sub-components of the Universe (like globular clusters) determines how the Universe will pan out. (much like Plasticine). When interactive forces become very small voids are created which are either worm holes or black holes, implying the creation of new "universes". This process can continue perpetually. The semantics of the word "Universe" are open to debate.