Cosmic clocks, cosmic variance and cosmic averages

Cosmic acceleration is explained quantitatively, purely in general relativity with matter obeying the strong energy condition, as an apparent effect due to quasilocal gravitational energy differences that arise in the decoupling of bound systems from the global expansion of the universe. “Dark energy ” is recognised as a misidentification of those aspects of gravitational energy which by virtue of the equivalence principle cannot be localised. Matter is modelled as an inhomogeneous distribution of clusters of galaxies in bubble walls surrounding voids, as we observe. Gravitational energy differences between observers in bound systems, such as galaxies, and volume–averaged comoving locations in freely expanding space can be so large that the time dilation between the two significantly affects the parameters of any effective homogeneous isotropic model one fits to the universe. A new approach to cosmological averaging is presented, which implicitly solves the Sandage-de Vaucouleurs paradox. Comoving test particles in freely expanding space, which observe an isotropic cosmic microwave background (CMB), possess a quasilocal “rest ” energy E = 〈γ(τ,x)〉mc 2: the lower bound refers to fiducial reference observers at “finite infinity”, which is defined technically