Late-time asymptotic dynamics of Bianchi VIII cosmologies

In this paper we give, for the first time, a complete description of the late-time evolution of non-tilted spatially homogeneous cosmologies of Bianchi type VIII. The source is assumed to be a perfect fluid with equation of state p = ((gamma) - 1)(mu), where (gamma)is a constant which satisfies 1 <= (gamma) <= 2. Using the orthonormal frame formalism and Hubble-normalized variables, we rigorously establish the limiting behaviour of the models at late times, and give asymptotic expansions for the key physical variables. The main result is that asymptotic self-similarity breaking occurs, and is accompanied by the phenomenon of Weyl curvature dominance, characterized by the divergence of the Hubble-normalized Weyl curvature at late times.