velocity dispersion

velocity dispersion

A measure of the spread of velocities of members within a cluster of galaxies or of stars. If both radius, R , and velocity dispersion, V , of a cluster are measured, an estimate of mass, V 2R /G , is obtained.

velocity dispersion

[və′läs·əd·ē di′spər·zhən] (physics) The root-mean-square value of the magnitudes of the random velocities of particles about their mean velocity.