Appendix E. Glossary of Terms.
Age of the Universe t0
Radioactive isotope studies yield ages of at least nine to sixteen billion years for our Galaxy, and the ages of the oldest star clusters put the limit at about 14 billion years.
The Universe is about 13.9 billion years (-1.4 to +1.7 billion years).
Source: University of Chicago, "Long Distance Discovery", Sky and Space June/July 2000 pp 26-27
"Evolution of the Galaxies"http://csep1.phy.ornl.gov/guidry/violence/galaxies-evol.html [Date accessed 11 Apr 2000]