If you divide the distance light traveled since the Big Bang by the Planck length, you get a factor of 8.17722722*10^60. ((1 / (70 ((km / s) / Mpc))) * (1 (light year / year))) / sqrt(((h / (2 * pi)) * G) / (c^3)) = 8.17722722 * 10^60 If you cube this value, you get the factor by which the volume was smaller. (((1 / (70 ((km / s) / Mpc))) * (1 (light year / year))) / sqrt(((h / (2 * pi)) * G) / (c^3)))^3 = 5.4678702 * 10^182 Try dividing the planck density by the current density of the universe. (5.1 * ((10^96) (kg / (m^3)))) / (5 * ((10^(-30)) (g / (cm^3)))) = 1.02 × 10^123 Presumably, the density of the universe would have to be greater than the planck density at planck time, by almost 60 orders of magnitude. But scientists say otherwise. Knowing that the scientists are more likely to be right than I, can somebody explain why this result is different by almost 60 orders of magnitude? Does the planck density ignore radiation and only consider massive particles? As an aside question, how would you calculate the electric permittivity and magnetic permeability of the universe at planck time?