Spacetime diagram comparison of our mixed (top) with a matter (middle) & a radiation (bottom) dominated universe

Left: proper, middle: comoving, right: conformal. For all 3 models at 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 axes: ↑: t & η, →: r & R

Color code: Comoving world lines | Hubble radius | Event horizon | Particle horizon | Light cone (past & future)

List of all diagrams: Static | Big Crunch | Big Rip | Radiation | Matter | Milne | Hyperbolic | Inflation | ΛCDM

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