Cosmological Parameters 2000

Abstract

The cosmological parameters that I emphasize are the age of the universe $t_0$, the Hubble parameter $H_0 \equiv 100 h$ km s$^{-1}$ Mpc$^{-1}$, the average matter density $\Omega_m$, the baryonic matter density $\Omega_b$, the neutrino density $\Omega_\nu$, and the cosmological constant $\Omega_\Lambda$. The evidence currently favors $t_0 \approx 13$ Gyr, $h \approx 0.65$, $\Omega_m \approx 0.4\pm0.1$, $\Omega_b = 0.02h^{-2}$, $0.001 < \Omega_\nu < 0.1$, and $\Omega_\Lambda \approx 0.7$.