A new formulation of the Friedmann-Lemaître-Robertson-Walker equation has been developed in a previous paper. The present study analyses an alternative approach to the cosmological constant Λ from the perspective of the so called CBU model (Continuously Breeding Universe). Instead of having a cosmological constant responsible for the expansion, an excess pressure is boosted by a "bang factor" β. It is assumed that expansion is caused by the continuous addition of matter, due to, say, electron-positron fluctuations. Even if only a fraction of virtual pairs "stay alive", while the majority returns to nothingness, the phenomenon is vigorous enough to explain the expansion. The momentum change due to the inflow of new matter provides a force and accordingly a pressure explaining the expansion. An equation of said pressure is derived and then interpreted as the equivalent to the cosmological 'constant', Λ_eq. The momentum pressure provides a perfect match to the dark energy density.

general relativity, cosmological constant, Friedmann's equation, Robertson-Walker metric, dark energy