How old is the Universe? Measuring the expansion rate with the Hubble Space Telescope

Abstract

One of the primary motivations for building the Hubble Space Telescope was to allow an accurate measurement of the age of the Universe. The author describes the Hubble Space Telescope and the Wide Field and Planetary Camera used for this effort. A brief historical summary is given. Early in this century, astronomer Edwin Hubble provided evidence that the Universe was expanding. However, an accurate value for this expansion rate has eluded astronomers for almost seven decades. Unfortunately, the measurement of the expansion rate has turned out to be much more difficult than anticipated by Hubble. The reasons for this difficulty, and the need for an increased resolution over what can be achieved using ground-based telescopes, are outlined. Finally, results from the Hubble Space Telescope are presented. The preliminary results from the Hubble Space Telescope yield an age for the Universe of 8 billion years. This age is younger than the ages measured for the oldest objects in the Galaxy. This paradox and the implications of these results are discussed.