A LOWER LIMIT ON THE AGE OF THE UNIVERSE

A detailed numerical study was designed and conducted to estimate the absolute age and the uncertainty in age (with confidence limits) of th e oldest globular clusters in our galaxy, and hence to put a robust lo wer bound on the age of the universe. Estimates of the uncertainty ran ge and distribution in the input parameters of stellar evolution codes were used to produce 1000 Monte Carte realizations of stellar isochro nes, which were then used to derive ages for the 17 oldest globular cl usters. A probability distribution for the mean age of these systems w as derived by incorporating the observational uncertainties in the mea sured color-magnitude diagrams for these systems and the predicted iso chrones, The dominant contribution to the width of the distribution (a pproximately +/-5 percent) resulted from the observational uncertainty in RR-Lyrae variable absolute magnitudes. Subdominant contributions c ame from the choice of the color table used to translate theoretical l uminosities and temperatures to observed magnitudes and colors, as wel l as from theoretical uncertainties in heavy element abundances and mi xing length. The one-sided 95 percent confidence limit lower bound for this distribution occurs at an age of 12.07 x 10(9) years, and the me dian age for the distribution is 14.56 x 10(9) years. These age limits , when compared with the Hubble age estimate, put powerful constraints on cosmology.