ABSTRACT
How old is the universe? The standard big-bang model of the origin of the universe
says that it expands uniformly, and locally, according to Hubble’s law:,
y = βx,
where y is the relative velocity of any two galaxies separated by distance x, and β is “Hubble’s constant” (in standard astrophysical notation y ≡ v, x ≡ d and β ≡ H0). β−1 gives the approximate age of the universe, but β is unknown and must somehow be estimated from observations of y and x, made for a variety of galaxies at different distances from us.
