This paper returns to the evolution of a Relativistic Domain Universe as developed in detail in [1]. Initially, the emergence of a definable boundary is discussed, so resulting in the establishment of the gravitational radius and thereby the 3a_u criterion. Three further subjects are then addressed.

The first, by analysing the gravitational acceleration experienced by a galactic celestial body in Phase I, shows how celestial material accumulates at the core in the form of a large number of adjacent masses in close proximity.

The next subject analyses the dynamic relationship between the physical and the gravitational radii. The result shows how the difference between these two parameters is reduced to the critical level, whereby the physical radius is equal to three times the gravitational radius, so initiating the second evolutionary phase.

The third subject concerns the second phase of evolution, and derives the physical radius of the Universe at the point of inflexion, i.e. the point at which the inward gravitational migration of all galactic bodies towards the centre, is halted by the repulsive gravity field generated within the Universe in the second phase. It also shows that the Acceleration Potential at the boundary at this point is always positive, thereby ensuring that the Universe starts to expand again.

For a full understanding of the material presented in this paper, it is essential that reference [1] be read thoroughly first.

In the interests of brevity, unless necessary for complete clarity, a parameter will only be defined in this paper if it has not previously been so in either [1] or [2], with which familiarity is assumed.