So I'm looking to find the distance light has traveled since matter - dark energy equivalence. Assume dark energy dominance from equivalence. Space-time has flat geometry and Ω0m = 0.315 , Ω0 = 1 Thus: Ω0Λ will equal Ω0 - Ω0m= 0.685 ρ0m (1 + zeq)3 = ρ0Λ where: ρ0m = ρ0c * Ω0m and: ρ0Λ = ρ0c * Ω0Λ I used this to find z = 0.296 Next, I need to use this somehow to find the light travel time. My guess is that I should use a solution of the Friedmann equation and use it to find a time? I haven't been able to figure out how to do this so far. I think I may just need to find the right Friedmann equation for dark energy dominance and work it out from there. But, it's missing from my notes and I don't know how to get there. Any pointers here guys?