The Universe is not expanding – the galaxies are simply falling toward boundary of a finite non-expanding universe. I estimate the universe to be a finite size of at least 100 billion light years across with the galaxies falling outward toward their respective parts of the boundary powered by a fifth force (Super Force) located at the boundary.
The size of the universe is determined by the laws of nature. Where these laws end, at the boundary, the universe ends, space itself ends – nothing can exist beyond the border. All the matter and energy that strike the boundary are absorbed. At the same time new massless matter is created to replace the absorbed matter. The energy that was absorbed at the boundary becomes the mass/gravity/energy of the matter as it accelerates toward the boundary.
Following the law of the conservation of matter and mass/energy, the amount of matter and energy within the universe remains constant at all times as does the size of the universe. The matter and energy, of the galaxies striking the boundary, that happened to be directed away from the boundary and not absorbed, travels back into the universe as high energy cosmic rays, quasar radiation, and background radiation.
The big bang theory itself infers there is a center of the universe with all the galxies rushing away from the origin. If we cannot see any evidence of a center with an anisotropy red shift it would indicate that the center is beyond our observable distance. The galaxies are all traveling in the same general direction toward the outer boundary of the universe. Our observable portion of the universe is just a small part of a much larger universe. (Similar in relation to a baseball within a basketball). If our portion of the observable universe was represented by the baseball we would never see the center or boundary of the finite universe but the galaxies within our observable portion of the universe would maintain their proper redshifts.
We are limited to the observable universe but it would be great to imagine what is going on in the regions beyond that we cannot see. The galaxies crashing into the border and being absorbed. The new massless matter being created in the central region. The new matter gaining mass/energy and therefore gravitational attraction as it begins its long journey of falling toward the border, The galaxies forming as they slowly accelerate (fall) toward the border. Our universe is a very old, very dynamic, constant state entity. Did the universe always exist or was it created? The anwer to that question will never be known and will always remain a speculation in the imagination of mankind.
refer: The MIND of Mankind – (chapter 14 – The Finite Universe)