The value of the Hubble constant is around 70 km s-1 Mpc-1. Consider two galaxies moving with the Hubble flow of the Universe that are currently separated by 1 Mpc and assume that the rate of expansion of the Universe is constant with time. A. At what time in the past were the galaxies coincident? This is presumably the origin of the Universe. B. In this non-accelerating Universe, how does the Hubble constant vary as a function of time? What was the Hubble constant when the Universe was half its current age? This should be an easy question, but I am having some trouble with it. I feel that (A) should just be Hubble Time right? If you guys could lead me in the right direction or give some hints that would be great.