In 1929, Hubble measured galaxies’ redshifts, showing the universe is expanding. This implies a dense origin point, supporting the Big Bang model. Expansion is still ongoing and accelerating due to dark energy. The rate of expansion, Hubble’s constant, affects estimates of the universe’s age. Modern measurements refine our understanding of cosmic history and expansion dynamics. Hubble’s work transformed cosmology from speculation to quantitative science.
It matters because galaxy redshifts confirm a dynamic universe originating from the Big Bang.
It also guides estimates of age, size, and future evolution of the cosmos.
Galaxies are still racing apart from the Big Bang’s aftermath.
Hubble Space Telescope [nasa.gov]