Tufts/CfA/MIT Cosmology Seminar, at MIT: Tsafrir Kolatt, Center for Astrophysics Title: The Power of Velocities Abstract: The peculiar velocity power spectrum is derived and related to the density fluctuations power spectrum. Constraints on theoretical power spectra are obtained by comparing the results to the COBE measurement of the CMB temperature flactuations. Constraints on the density parameter, Omega, and the galaxy biasing parameters are derived by comparison to galaxy power spectra.