We argue that the geodesic hypothesis based on autoparallels of the Levi-Cività connection may need refinement in the scalar-tensor theories of gravity. Based on a reformulation of the Brans-Dicke theory in terms of a connection with torsion determined dynamically in terms of the gradient of the Brans-Dicke scalar field, we compute the perihelion shift in the orbit of Mercury on the alternative hypothesis that its worldline is an autoparallel of a connection with torsion. If the Brans-Dicke scalar field couples significantly to matter and test particles move on such worldlines, the current time keeping methods based on the conventional geodesic hypothesis may need refinement.
In this paper for the first time the role of gravitational scalars on the motion of the planet mercury was explored and the results confronted with experimental data. This paper led to further developments in the Brans-Dicke formulation of gravitation RAE_import_type : Journal article RAE_uoa_type : Physics