Edwin Hubble's 1929 observation linked galaxy recession speed to distance. The slope H₀ is one of cosmology's most contested constants.
Explore interactively
Open equation pagev = H₀d — distant galaxies recede faster, evidence that the universe is expanding.
7 min read · 2026-06-11
Edwin Hubble's 1929 observation linked galaxy recession speed to distance. The slope H₀ is one of cosmology's most contested constants.
Explore interactively
Open equation page