Evolution of the cosmic horizons in a closed radiation universe (Ωr=2)
Proper (r) & comoving (R) distances, Plot range: r|R=0…70, t=0…41.1856
If H=67.15 at a=1, the turning point at a=√2 would be at t=20.5928 Gyr
The big bang is at the bottom, the big crunch at the top of the t axis
Gray dashed curves: worldlines of objects comoving with the Hubbleflow
+: static (ȧ=ä=0), matter (Ωr=1), radiation (Ωr=1), mixed (Ωr+Ωm+ΩΛ=1)
