Univers en expansion

Animate cosmic expansion in a flat ΛCDM universe. The scale factor obeys

H(a)/H₀ = E(a) = √(Ω_r/a⁴ + Ω_m/a³ + Ω_Λ + Ω_k/a²)

with cosmic time t = ∫ da/(a H(a)). Galaxies sit at fixed comoving coordinates while the grid stretches with a(t). Press Run to animate from early a to today (a=1).