Cosmology and a General Scalar-Tensor Theory of Gravity

The cosmological models resulting from a general scalar-tensor theory of gravity are discussed. Those models for which the scalar field varies as a power of the cosmological expansion factor $$(\text{i}.\text{e}.\,\phi \,\propto \,{R}^{n})$$ are considered in detail, leading to a set of such models compatible with observation. This set includes models in which the scalar coupling parameter ω is negative. The models described here are similar to those of Newtonian cosmology obtained from an impotence principle.