Parametric down-conversion (PDC) and parametric up-conversion (PUC) had been experimentally observed as spontaneous energy conservation processes. The first one could increase cosmic entropy by decreasing energy density. In a Casimir effect experiment could be calculated that the space between plates contracts, because PUC allows that from every two, low energy Cosmic Microwave Background (CMB) photons could be created one of higher energy. This decrease in photon number and increase in photon energy density allow shrinking of the volume of CMB photon localization. This effect reduces initial volume to 6.25% per each pair of integrated photons. This process would be observable as a decrease of the space separating the parallel plates. The higher energy photons are generated from CMB-containing (constituted?) vacuum, and therefore, could be inconsistently attributed as coming out of nothingness an assumption reserved to virtual energy in accordance to Heisenberg’s uncertainty principle. CMB is subject to gravity, but its elongation by PDC is not. Accordingly, PDC present splitting CMB rate was evaluated as equivalent to that of the Hubble’s constant (H 0 ). PDC continuously generates new photons, the summa of their radius could be assumed to reach a length of about to 70 km per Mpc per second. This value, because the photons emerge uniformly into space, would add as the summa of the number of parsecs that separates two galaxies. Accordingly, multiplying the PDC equivalent to H 0 70 km/sec by a distance of about 4300 Mpc, the inter-galactic velocity of recession would approach that of the propagation of light in vacuum. However, the photon themselves are only expanding to expand CMB intergalactic vacuum.