An Etymological Dictionary of Astronomy and Astrophysics

The observed peculiar velocities of galaxies in the → redshift space of → galaxy clusters when the galaxies undergo → infall toward a central mass.
This → redshift space distortion differs from the → fingers of God in that the peculiar velocities are not random, but correspond to the coherent falling of galaxies toward the central mass. See also → peculiar velocity.

See also: Kaiser, N., 1987, MNRAS 227, 1; → effect.