If we consider the observed distance z from us according to the model of curved space with a constant radius of curvature R as measured along the arc z = R·φ, where φ is the central angle of this arc, then for a closed circle we cannot consider any observed element as more distant than half of the circle for φ=π. And we call such a distance the SIZE of UNIVERSE and denote it as Rv = R·π. Because any observed object for φ>π would actually already be observed in the opposite direction for φ<π. However, we cannot include such an object in the Universe twice, because it cannot even be in the Universe twice.
But we also called the expansion of curved space with a constant radius of curvature R, which expansion is the same in all places, as ECSTASY of space. If we consider this expansion as if at a constant speed dR/dt = ΔV0 >0, then not only the observed distance z = R·φ but also the observed speed of receding ΔV = ΔV0·φ must appear to us as linearly increasing with the central angle φ measured from us. And we called the limit of such an increase in the observed speed, when ΔV=c and where c is the speed of light, as the LIGHT BARRIER of the Universe SBV, beyond which we can no longer observe the Universe.
And to this LIGHT BARRIER we also assigned the time term AGE of UNIVERSE Vv assuming that light spread to us along the entire path at a constant speed c. It is therefore such a time interval during which the Universe expanded by ECSTASY, up to a size that I will distinguish by the name Observable SIZE of UNIVERSE RPv= ΔV0•Vv.