Yes, it is hard Helio My post #23 shows what happens extrapolating H0 with GR expansion beyond the comoving radial distance of the postulated 1100 redshift for the CMBR. You run into more space, expanding even faster Extrapolating backwards to the *beginning*, you land in a singularityThat would require infinite space and that is contrary to my understanding of BBT. I keep thinking about the claims that, just after Inflation, the universe was about the size of a grapefruit (or beach ball from one source). It's hard enough for the mind to grasp the 90+ billion lyrs. diameter today.