The Distance of the Virgo Cluster

Until the discovery (Corey & Wilkinson, 1976) of the anisotropy of the cosmic microwave background, the Virgo cluster represented something like a Rosetta Stone for many observational cosmologists: in the absence of a significant peculiar velocity component for the Local Group in the direction of the Virgo cluster, its distance, accurately measured, might reveal the global expansion rate and the Hubble age. Although this simple picture has changed, the distance of the Virgo cluster remains important, partly for a sharper understanding of the properties of rich clusters and the galaxies they contain, but more importantly (for my purposes here) as an interesting distance over which we may test various constructions of the extragalactic distance scale.