Estimating Milky-Way Dark Matter: Its Amount and Distribution

摘要

The fate of the universe is determined by its average mass density, whether it is open or closed, or by gravitational braking of the Hubble expansion hovering on the threshold between open and closed. The present research gives size and distribution of a possible dark-matter contribution to the average mass density of the universe; it connects two research efforts. Big Bang Nucleosynthesis [BBNS] calculates the relative abundances of the light elements formed during the first moments of the universe as a function of average mass density (Riordan and Schramm, 1991). These estimates show nuclear-type matter provides less than 10% of the mass-density needed to close the universe. Dark matter is a possible source of additional mass-density which may relate to the ultimate fate of the universe, and dark matter is suggested to explain the discovery of a flat rotation curve found for stars in the Milky Way galaxy (Rubin, 1991).