I would just like to put it out there that I do believe that the Big Bang was a cosmic occurance. However, I have been asked to argue the fact that there was a point in the past when the density of the universe was infinite.
I know that the best way to argue this point is by using the formula relating expansion rate (H) and energy density (ρ). This formula is: H^2 = (8πG)ρ/3.
In my opinion, I could go about this in two ways:
- The energy density is energy/volume, and so the way for density to = infinity is that energy is infinity. So there must have been a poing in time where the energy was infinitely large enough to create this expansion.
- Expansion rate = (8πG)ρ/3 where (8πG)/3 are all constants, and so if the expansion rate was to increase by an infinate amount, the energy density must be the only aspect of the formula that increases by that amount as well, thus implying that energy density was at one point infinate.
