John. W. Moffat

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A covariant scalar-tensor-vector gravity theory is developed which allows the gravitational constant G, a vector field coupling ω and the vector field mass µ to vary with space and time. The equations of motion for a test particle lead to a modified gravitational acceleration law that can fit galaxy rotation curves and cluster data without non-baryonic dark(More)
A fully relativistic modified gravitational theory including a fifth force skew symmetric field is fitted to the Pioneer 10/11 anomalous acceleration. The theory allows for a variation with distance scales of the gravitational constant G, the fifth force skew symmetric field coupling strength ω and the mass of the skew symmetric field µ = 1/λ. A fit to the(More)
The dynamical consequences of a bimetric scalar-tensor theory of gravity with a dy-namical light speed are investigated in a cosmological setting. The model consists of a minimally-coupled self-gravitating scalar field coupled to ordinary matter fields in the standard way through the metric: gµν +B∂µφ∂νφ. We show that in a universe with matter that has a(More)
The spontaneous breaking of local Lorentz invariance in the early Universe, associated with a first order phase transition at a critical time t c , generates a large increase in the speed of light and a superluminary communication of information occurs, allowing all regions in the Universe to be causally connected. This solves the horizon problem, leads to(More)
A gravity theory is developed with the metricˆg µν = g µν +B∂ µ φ∂ ν φ. In the present universe the additional contribution from the scalar field in the metricˆg µν can generate an acceleration in the expansion of the universe, without negative pressure and with a zero cosmological constant. In this theory, gravitational waves will propagate at a different(More)
The gravitational wave solutions obtained from a perturbation about confor-mally flat backgrounds in Einstein gravity are investigated. A perturbation theory analysis of the Lesame, Ellis and Dunsby results, based on a covari-ant approach, shows that for gravitational waves interacting with irrotational dust, the equations are linearization unstable. The(More)