{i} (Astronomy) scientific law that states that the speed at which distant galaxies move away from Earth is proportional to their distance from the observer
(astronomy) the generalization that the speed of recession of distant galaxies (the red shift) is proportional to their distance from the observer
states that the velocity at which a distant object is receding from the Earth (as measured by its redshift) is proportional to its distance; observational evidence for an expanding universe