The age and size of the universe.

Modern distance determinations to galaxies were reviewed and placed on a uniform and self-consistent scale. Based on eight separate but not entirely independent techniques, the distance to the Virgo cluster was found to be 15.8 +/- 1.1 megaparsec. Twelve different determinations yield a Coma/Virgo distance ratio of 5.52 +/- 0.13 and hence a Coma distance of 87 +/- 6 megaparsec. With a cosmological redshift of 7210 kilometers per second, this gives a Hubble parameter H(0) (local) of 83 +/- 6 kilometers per second per megaparsec. From the velocity-distance relation of rich clusters of galaxies, the ratio of the value of H(0) (global) to the value of H(0) (local) was determined to be 0.92 +/- 0.08. In other words, the cluster data do not show a statistically significant difference between the local and global values of the Hubble parameter. If one nevertheless adopts this relation between H(0) (global) and H(0) (local), then the value of H(0) (global) is 76 +/- 9 kilometers per second per megaparsec. This observed value differs at the approximately 3sigma level (where sigma is the standard deviation of the distribution) from values in the range 36 less, similar H(0) less, similar50 kilometers per second per megaparsec, which are derived from stellar evolutionary theory in conjunction with standard cosmological models with a density parameter (Omega) that is equal to 1 and a cosmological constant (lambda) that is equal to 0.