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)
A dynamical model for varying light velocity in cosmology is developed , based on the idea that there are two metrics in spacetime. One metric g µν describes the standard gravitational vacuum, and the otherˆg µν = g µν + βψ µ ψ ν describes the geometry through which matter fields propagate. Matter propagating causally with respect tô g µν can provide(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)
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 field equations in the nonsymmetric gravitational theory are derived from a Lagrangian density using a first-order formalism. Using the general covariance of the Lagrangian density, conservation laws and tensor identities are derived. Among these are the generalized Bianchi identities and the law of energy-momentum conservation. The Lagrangian density(More)
BACKGROUND National campaigns focusing on key symptoms of bowel and lung cancer ran in England in 2012, targeting men and women over the age of 50 years, from lower socioeconomic groups. METHODS Data from awareness surveys undertaken with samples of the target audience (n=1245/1140 pre-/post-bowel campaign and n=1412/1246 pre-/post-lung campaign) and(More)
Two variable speed of light models and their physical consequences are investigated. It is ten years ago that an alternative solution to the initial value problems of cosmology based on a variable speed of light (VSL) was published [1]. The model was based on the idea that in the very early universe at a time t ∼ t P ∼ 10 −43 sec., where t P denotes the(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)