1. The problem statement, all variables and given/known data Show that by using the Friedmann-equation you can determine the scale factor for a Universe in it's early stages (starting with the Big Bang) to: 2. Relevant equations The equation for the scale factor: Where r(t) is the distance from us to a given galaxy to the time t and r0 is the galaxies current distance from us. And the Friedmann equation: 3. The attempt at a solution I'm dumbfounded and I have no idea of what to do. This is for a major paper and any help is much appreciated. If you don't understand the problem, please do say so and I'll try and clear it up. Thanks a lot!