If we start with Einstein’s beautiful hypothesis that test particles in gravitational field move along geodesic lines of some Riemannian spaces V4, it is natural to expect that the differential equations for finding the metric tensor gαβ(x) for a given distribution of matter also should be invariant under any transformations at which the geodesic equations remain invariant. However, the geodesi...

A general method of regularisation of classical self interaction in strings is extended from the electromagnetic case (for which it was originally developed) to the gravitation case, for which the result can also be represented as a renormalisation.

In the context of the fact that the existence of dark energy causing the accelerated expansion of the universe has been confirmed by the WMAP and the Sloan Digital Sky Survey, we reexamine gravitation itself, starting with the formulation of Sakharov and show that it is possible to obtain gravitation in terms of the electromagnetic charge of elementary particles, once the ZPF and its effects at...

Gunnar Nordström constructed the first relativistic theory of gravitation formulated in terms of interactions with a scalar field. It was an important precursor to Einstein’s general theory of relativity a couple of years later. He was also the first to introduce an extra dimension to our spacetime so that gravitation would be just an aspect of electromagnetic interactions in five dimensions. H...

This essay argues that when measurement processes involve energies of the order of the Planck scale, the fundamental assumption of locality may no longer be a good approximation. Idealized position measurements of two distinguishable spin-0 particles are considered. The measurements alter the space-time metric in a fundamental manner governed by the commutation relations [xi pj] = ih̄ δij and th...

A covariant theory of gravitation in flat space-time is stated and compared with general relativity. The results of the theory of gravitation in flat space-time and of general relativity agree for weak gravitational fields to low approximations. For strong fields the results of the two theories deviate from one another. Flat space-time theory of gravitation gives under some natural assumptions ...