A quick follow up question.
If Hubble's constant changes over time, surely each distant galaxy you observe would have a different value for H = v/d seeing as their light was emitted at different times in the past so Hubble's constant was different for each of them. But as I understand it...
Is I understand it Hubble's law states that V = Hd = dx/dt
Solving this differential equation, I got d = kexp(HT) where k is an arbitrary constant.
This implies d²x/dt² = Hv = H²d and dⁿx/dtⁿ = Hⁿd.
However (at least for me), finding the value of k is a problem, for 1, it must vary from galaxy...