Ratio of outward speed of galaxies to their distances from Earth.
(cosmology) the ratio of the speed of recession of a galaxy (due to the expansion of the universe) to its distance from the observer; the reciprocal of the Hubble constant is the age of the universe
(cosmology) the ratio of the speed of recession of a galaxy (due to the expansion of the universe) to its distance from the observer; the Hubble constant is not actually a constant, but is regarded as measuring the expansion rate today
