Hubble measured the velocity of the movement of galaxies by using

Hubble measured the velocity of the movement of galaxies by using Hubble's law states that galaxies located farthest from the center of the universe than those closest to the center.

Explanation:

Hubble's Law says that an object's velocity away from an observer is directly proportional to its distance from the observer. In other words, the farther away something is the faster it is moving away from us. The spectrum of a galaxy allows you to measure its redshift.

Answer:"the Doppler Effect" and, "are moving faster."