Lunatic on a mountain : Fritz Zwicky and the early history of dark matter

Abstract

Fritz Zwicky is identified commonly as the discoverer of dark matter, the unobservable mass that is believed to occupy about 90 percent of the universe. In 1933 Zwicky found a mass discrepancy in the Coma cluster of galaxies, and in 1936 a similar discrepancy was found in the Virgo cluster. The startling news of a mass discrepancy in clusters did not raise many eyebrows. In fact, the astronomical community did not address the problem until the occasion of two conferences held in 1961, and it only gained astronomical prestige at the end of the 1970s, forty years after the initial postulation. Zwicky's role in the history of this most important subject in astronomy is significant in tracing the progression of the understanding of extragalactic dynamics and observations. It also shows that it is not only scientific evidence that defines theories, but that social interactions are also of vital importance.