The observational determination of the age of the universe as a laboratory exercise

It is now practical for undergraduate students to carry out a laboratory exercise in which they determine an approximate age for the universe using their own data. Because of the wide availability and excellent performance of charge-coupled device cameras designed for astronomy, a relatively small telescope with a modest spectrograph is sufficient to carry out the necessary observations. The age determination rests on a measurement of the Hubble constant, which, in this experiment, is derived from the measured distance and velocity of recession of a single galaxy. The distance is determined from an image of the galaxy, while the velocity is obtained from a measurement of the redshift of the spectrum of the galaxy. Examples of such observations made at a small college observatory are presented and the extraction of an estimate of the age of the universe from those data is described. (C) 1999 American Association of Physics Teachers.