Related papers: Einstein's E = mc^2 mistakes
These notions in the title are of fundamental importance in any branch of physics. However, there have been great difficulties in finding physically acceptable definitions of them in general relativity since Einstein's time. I shall explain…
In this paper, we first review Huei's formulation in which it is shown that the linearized Einstein equations can be written in the same form as the Maxwell equations. We eliminate some imperfections like the scalar potential which is ill…
The historical and conceptual foundations of General Relativity are revisited, putting the main focus on the physical meaning of the invariant ds, the Equivalence Principle, and the precise interpretation of spacetime geometry. It is argued…
The confrontation between General Relativity and experimental results, notably binary pulsar data, is summarized and its significance discussed. The agreement between experiment and theory is numerically very impressive. However, some…
In 1905 A. Einstein, from the experiments of Michelson and Morley in 1887, enunciates the light speed constancy principle in the inertial frames of reference. However, this principle was pointed by the equations of the electromagnetism of…
This note is by no means a comprehensive study of Minkowski's space-time formalism of special relativity. The mathematician, Hermann Minkowski was Einstein's former mathematics professor at the Z\"urich Polytechnic. During his studies at…
This note is devoted to a detail concerning the work of Albert Einstein and Peter Bergmann on unified theories of electromagnetism and gravitation in five dimensions. In their paper of 1938, Einstein and Bergmann were among the first to…
We propose a revised formulation of General Relativity for cosmological settings, in which the Einstein constant varies with the energy density of the Universe. We demonstrate that this modification has only phenomenological impact of…
The intermediate stage of the development of general relativity is inseparable of Marcel Grossmann's mathematical assistance. Einstein acknowledges Grossmann's help during 1912-1914 to the development of general relativity. In fact, as with…
Careful analysis of parametrized variational principles in mechanics and field theory leads to a generalization of Einstein theory that includes a cosmological stress tensor. This generalization also follows by restricting variations of the…
The Einsteinian Theory of Gravitation ("General Theory of Relativity") is founded essentially; on the reception that the geometrical properties of the 4-dimensional space-time continuum are defined from the matter in it. Contrary to this,…
This article reviews the biography of the Swiss mathematician Marcel Grossmann (1878-1936) and his contributions to the emergence of the general theory of relativity. The first part is his biography, while the second part reviews his…
This remodeled form of Einstein's relativity theories retains and incorporates only experimentally proven principles. It is based on a generalized law for spinning and rotational motions, which is in fact the conservation law of momentum…
The first results of Einstein-Maxwell equations established by Raincih in 1925 are therefore called the Raincih conditions. Later the result was rediscovered by Misner and Wheeler in 1957 and made the basis of their geometrodynamics. The…
This commentary reflects on the 1930 discoveries of L\'eon Rosenfeld in the domain of phase-space constraints. We start with a short biography of Rosenfeld and his motivation for this article in the context of ideas pursued by W. Pauli, F.…
The mysterious `dark energy' needed to explain the current observations, poses a serious confrontation between fundamental physics and cosmology. The present crisis may be an outcome of the (so far untested) prediction of the general theory…
Taking a hint from Dirac's large number hypothesis, we note the existence of cosmologically combined conservation laws that work to cosmologically long time. We thus modify Einstein's theory of general relativity with fixed gravitation…
In a previous work we have shown that the null result of the Michelson-Morley experiment in vacuum is deeply connected with the notion of time. The same is true for the the postulate of constancy of the two-way speed of light in vacuum in…
There is general agreement that the universe began with an "explosion" of matter and energy at a "singularity", the "Big Bang". This paper analyses the mechanics of that beginning and two alternative theories related to it: - The…
This paper deals with four topics: The first subject is Abraham's spherical electron, Lorentz's contracted electron and B\"ucherer's electron. The second topic is Einstein's 1905 relativity theory of the motion of an electron. Einstein…