Expanding Universe Simulator

This simulator solves the Friedmann equation live and plays the result back as a 3D field of galaxies uniformly stretching apart from a fixed observer at the center. Adjust the matter density (Ωm), dark energy density (ΩΛ) and the Hubble constant (H₀) to see how the balance between gravity's pull and dark energy's push decides the universe's fate: gentle accelerating expansion near the real Lambda-CDM values, decelerating coasting when matter dominates, or a full recollapse into a Big Crunch when the implied curvature is closed. The scale factor a(t) and instantaneous Hubble parameter H(t) update in real time, and the camera pulls back automatically as the field grows so the whole galaxy population stays in frame.