During evolution, cosmic thermal energy density is always directly proportional to the critical mass-energy density. The product of cosmic ‘critical density’ and ‘critical Hubble volume’ can be called as the ‘critical mass’ of the evolving universe. With reference to Mach’s principle, cosmic ‘critical density’, ‘critical volume’ and ‘critical mass’ can be considered as the quantified back ground dynamic properties of the evolving universe. By considering the Planck mass as the critical mass connected with big bang, Planck scale Hubble constant and critical density can be defined. Observed redshift can be reinterpreted as a cosmological light emission phenomenon connected with cosmologically reinforcing or strengthening hydrogen atom. Super novae dimming can also be understood in this way. To understand the ground reality of cosmic rate of expansion, accuracy of the current methods of estimating the magnitudes of current Hubble’s constant and current CMBR temperature must be improved.