text: how does the universe contrtacts?   the universe is expanding. whether it will contract or not depends on the amount of "dark matter" in the universe, which since we can't see all of it we really don't know how much there is. if there's enough dark matter the additonal gravity will stop the expansion and eventually the universe will start contracting, otherwise if there isn't enough dark matter, it will just keep expanding and never contract. see the attached link "crisis in cosmology".