Comparison of our mixed component universe (top) with a pure matter (middle) and a pure photon (bottom) universe

Left: proper distances, right: comoving distances. For all 3 models @ a=1 the Hubbleparameter H=67.15 km/sec/Mpc

Top row: Ωr=0.000092136, Ωm=0.315, ΩΛ=1-Ωr-Ωm; middle row: Ωm=1; bottom row: Ωr=1. Plot units: ↑t=Gyr, →r&R=Glyr

Colors: Hubble radius (rH), event horizon (rE), particle horizon (rP), light cone (rL), comoving world lines (a)

In the universes without dark energy (ΩΛ=0) there's no event horizon (rE=RE=∞) since RP & RH grow without bounds

Lightcone origin: ↑ t=13.842 / ↓ t=50

Simon Tyran, Vienna (CC BY 4.0)                          Index:     a, ȧ, ä, ã, â, H, , , rH, rE, rP, rL, Σr, Ω