Cosmological solutions of the Einstein-Friedmann equations ...

Cosmology
The conclusion of the above discussion: provided Λ = 0 and p = 0, we may
determine the age and the curvature of the universe by evaluating the observable
relations at t = t0. Since, in principle, we can determine H0 and ρ0 independently,
we can find whether k = 0, +1 or − 1. The density ρEdS for k = 0, shows up as the
critical density. Generally,
ρ(t) = ρEdS(t) · 2 q(t)
such that
ρ0 > ρ0 EdS ✄ k = 1
Thus:
ρ0 < ρ0 EdS ✄ k = −1
● Lot of matter – space closes under gravity, gravity wins.
● Little matter – space is open and matter spreads forever.
c○ 2009, F. Jegerlehner ≪❘ Lect. 7 ❘≫ 455