there is a theory that gravity could have called could pull back galaxies back together causing a reverse Big Bang which observation makes a theory less likely than the idea that the Universe make you continue to expand
As the universe will continue to expand the galaxies are getting far away from each other and all this has started about 5 billion years ago. Thus the universe will accelerate and expand at a much faster rate and this will grow outwards an give the universe a linger life cycle.
