  We point out that the mass of the cosmos on gigaparsec scales can be
measured, owing to the unique geometric role of the maximum in the areal
radius. Unlike all other points on the past null cone, this maximum has an
associated mass, which can be calculated with very few assumptions about the
cosmological model, providing a measurable characteristic of our cosmos. In
combination with luminosities and source counts, it gives the bulk mass to
light ratio. The maximum is particularly sensitive to the values of the bulk
cosmological parameters. In addition, it provides a key reference point in
attempts to connect cosmic geometry with observations. We recommend the
determination of the distance and redshift of this maximum be explicitly
included in the scientific goals of the next generation of reshift surveys. The
maximum in the redshift space density provides a secondary large scale
characteristic of the cosmos.
