A special-relativistic approach to gravitation and its astrophysical consequences

In the framework of Rastall's conservative program for the construction of gravitation theory we present a variant of modified classical gravitation theory based on Einstein's energy-mass equivalence principle. We pursue further the special-relativistic arguments and obtain a theory for the static spherically-symmetric gravitation field that is based only on the well-established physical principles and accounts for all experimental tests known in gravitation. Some astrophysical consequences of the modified classical gravitation theory (e.g., the non-existence of black holes, the creation of real particles in a strong gravitation field) are also discussed.     

Is there GR in the bimetric scalar-tensor theory of gravitation?

A theory of gravitation with a flat background metric and a dynamical variable (variable gravitational constant) is investigated. It is shown that such bimetric scalar-tensor theory (BSTT) generalized GR as all the solutions of GR equations and(x) = constant satisfy BSTT equations, firstly, and BSTT equations contain non-Einstein solutions with the variable, secondly. Due to this fact, the problem on the agreement of BSTT with the observational data is reduced to the problem on the agreement of GR with the observational data and to the interpretation of the solutions with the variable. The latter may prove useful for the prediction of new effects. Examples of such effects are discussed.     

The Ω-field theory of gravitation and cosmology

The present paper presents, within the Einstein conceptual framework, a scalar field theory of gravitation. The -field, however, is not superimposed on the space-time manifold from outside the given geometry but is derived from the space-time torsion which is shown to be the generator of gravitation and inertia as well as spin. The theory predicts the three crucial tests of gravitation to the same degree of accuracy as does Einstein's theory. But it also predicts gravitational radiation emitted by a pulsating sphere and a singularity free cosmology in contradiction to Einstein's results. Above all, the scalar gravitational field can be easily quantized in the present context.     

Post-newtonian gravitational radiation from binary systems in flat space-time theory of gravitation

For a previously studied theory of gravitation in flat space-time a general formula of the gravitational radiation at large distances from a system of bodies is derived. The calculations are carried out through post-Newtonian order within this theory of gravitation. A more explicit formula is given for a binary system. It agrees with the result of general relativity.     

The gravitation theory in bimetric formulation

The gravitation theory is considered in bimetric formulation with a Lagrangian of the most common type and quadratic with respect to the derivativesg _ik/l of the metric tensor. Restrictions on the dimensionless parameters of the theory are found, basing on the comparison with the Newtonian theory and the analysis of corresponding observational data in the vicinity of the solar system. Propagation of the weak gravitation waves is investigated in the outside gravitational field.     

Qualitative behaviour of the trajectories of test bodies in five-dimensional spherically-symmetric gravitational field

Qualitative behaviour of the trajectories of test bodies is investigated in the five-dimensional gravitation theory for the spherically-symmetric solution. The Binnet formula is obtained for the trajectory. The region of the existence of circular trajectories as well as the regions of their stability are specially investigated using the method of numerical calculations. The values of the free parameters in the five-dimensional gravitation theory are estimated for the solar system.     

Accretion disks in bimetric theory of gravitation. A strong field test of general relativity?

The sensitivity of accretion disk models with respect to its inner boundary conditions, being located in the strong gravity region of a highly compact central body, is used to discuss a possibility of strong field tests of gravitation via compact source observations. Within the bimetric theory of gravitation the optically thin bremsstrahlung model is calculated as an example for this possibility. Using this model to describe the innermost region of the “bimetric disk”, significant differences with respect to the corresponding results in Einstein's theory were found. The more massiv and compact “bimetric disk” radiates softer with higher luminosity.     

行星磁场与卫星引力及其相对运动的统计关系

从知道某些天体具有磁场起，人们就对其磁场的起源提出种种解释，例如有电池说，转子说，化石说，发电机说等等。但由于这些学说都分别与某些观测事实相抵触而未被公认，因此星球磁场的起源一直是未能解决的命题。余先河先生提出，星球的磁场起源可能与所受的引力有关，行星的磁场强度正比于其所受卫星的引力；正比于卫星与行星的引力连线转动的相对角速度。本文对这两方面的命题分别进行了相关分析，得到其相关系数分别为：ｒ＝０．８４８１和ｒ＝０．８４２５，它们都在ａ＝０．０１的信度水平上相关。结果表明余新河关于行星磁场起源的设想是有基础的。本文还对其统计结果和可能机制进行了讨论。     

Post-Newtonian approximation of gravitation theory in flat space-time

The post-Newtonian approximation of the gravitational field of a perfect fluid for a previously stated theory of gravitation in flat space-time is studied. The conservation laws of energy-momentum and angular-momentum are derived and the equivalence of the conservation law of energy-momentum and the equations of motion is shown to the studied accuracy. The equations of motion are stated. All the results of the post-Newtonian approximation of the gravitation theory in flat space-time and of the general theory of relativity, as considered by Will in his famous book, agree to the studied accuracy.     

Exact Bianchi type II, VIII and IX string cosmological models in General Relativity and self-creation theory of gravitation

Exact Bianchi type II, VIII and IX String cosmological models are obtained in Einstein’s theory of gravitation and Barber’s (1982) second self-creation theory of gravitation. Some physical and geometrical properties of the models are also discussed.     

Bianchi type-V anisotropic cosmological models in certain theories of gravitation with perfect fluid distribution

Exact Bianchi type-V cosmological models are presented in Einstein’s theory of gravitation with cosmological constant Λ in case of perfect fluid distribution. Also obtained Bianchi type-V cosmological models in a scalar-tensor theory of gravitation proposed by Saez and Ballester (1986) in case of perfect fluid distribution using and without using negative constant deceleration parameter. Some physical and geometrical properties of the models are also discussed.     

Plane-symmetric vacuum in self-creation cosmology

Vacuum field equations for the static and non-static plane-symmetric metric are obtained in self-creation theory of gravitation proposed by Barber (1982). It is shown that, in both static and non-static cases, the only plane-symmetric solution in vacuum is the empty flat space-time of Einstein's theory. It is observed that this result is quite different from that of the Brans-Dicke and other scalar-tensor theories of gravitation.     

Working with Fred on action at a distance

This paper reviews the work the author carried out with Fred Hoyle on the development of electrodynamics and gravitation as direct particle theories. In this account the author reviews how the work was started, and went through stages of increasing sophistication, e.g., extending the Wheeler-Feynman electrodynamics to curved spacetime, its consequences in different cosmologies, and the issues arising from its quantization. The resolution of ultraviolet divergences in quantum electrodynamics is also briefly discussed. The parallel development of a Machian theory of gravitation followed the lead from electrodynamics. In both theories one sees a strong link between the large scale structure of the universe and local physics, as might be expected from an action-at-a-distance framework. It is recalled why Fred considered this an important aspect of a physical theory. This revised version was published online in August 2006 with corrections to the Cover Date.     

Photospheric Abundance Peculiarities in RS CVn Binaries

It is shown that Kantowski–Sachs cosmological models do not exist in Rosen's (1973) bimetric theory of gravitation when the source of gravitation is either perfect fluid or cosmic string. Hence, the vacuum model is constructed.     

Polteilchen in der TREDERSchen Tetradentheorie

In the framework of TREDERS ' tetrad theory of gravitation the interaction of pole-particles is considered in post-NEWTON ian approximation. The perihelion shift for the two-body problem is calculated for different matter-field-couplings. In general it depends not only from the sum of the masses but also from the reduced mass. The additional term is connected with the absorption of gravitation.     

On Some Bianchi Type Cosmological Models in a Bimetric Theory of Gravitation

Spatially-homogeneous and anisotropic Bianchi type-III, V, VI₀ cosmological models in Rosen's (1973) bimetric theory of gravitation are considered. It is shown that, in each case, when the soure of the gravitation field is a perfect fluid distribution Bianchi type cosmological models do not exist. Hence vacuum models are presented and studied. This revised version was published online in July 2006 with corrections to the Cover Date.     

Anisotropic fluid distributions in bimetric general relativity

Static and spherically-symmetric solutions of the field equations in the bimetric theory of gravitation are obtained for isotropic and anisotropic distributions of matter when the physical metric admits a one-parameter group of conformal motions. The solutions agree with Einstein's general relativity for physical systems comparable to the size of the Universe, such as the solar system.     

The model of a flat (Euclidean) expansive homogeneous and isotropic relativistic universe in the light of the general relativity,quantum mechanics,and observations

Assuming that the relativistic universe is homogeneous and isotropic, we can unambiguously determine its model and physical properties, which correspond with the Einstein general theory of relativity (and with its two special partial solutions: Einstein special theory of relativity and Newton gravitation theory), quantum mechanics, and observations, too.     

Vacuum friedmann model in self-creation cosmology

The field equations of the self-creation theory of gravitation proposed by Barber are solved for a vacuum with the aid of a space-time metric of Friedmann. Some physical properties of the solution are discussed.