Abstract:
In this paper, it is proved that the small deformation strain tensor can be
used instead the fundamental metric tensor of the GeneralTheoryofRelativity,
in order to formulate a DynamicTheoryofGravitation. Also, a solution
of the velocity of the gravitational interactions is given in terms of the escape
velocity due to the apparent size of the heavenly bodies. This last paragraph is
the motivation and the importance of the study here presented. Thus, when it has
a couple of celestial bodies separated by a distance in space, its apparent sizes
as seemed at a distance play a special role in the gravitational interactions. This
is so because of some effect over the size due to the very big distance in space.
In that situation, the values of their escape velocities are dependent on their
mass, and critically on their apparent radius. It is proved that they are the medium
used by the gravity to transmit its effects like propagating force of nature. Then,
when the escape velocities meet in some point of the space between the bodies, they
pull each other; because they are the carriers of the respective attractive gravitational
fields. In other words, the escape velocity due to the apparent size is the exchanging
coin in the gravitational interactions. Also it is proposed that such a dynamic
process is the responsible for the strong link which is established between any
couple of interacting heavenly objects in the Universe.

Abstract:
The answer to the question, what physical meaning should be attributed to the so-called boost-rotation symmetric exact solutions to the field equations of general relativity, is provided within the general interpretation scheme for the ``theories of relativity'', based on group theoretical arguments, and set forth by Erich Kretschmann already in the year 1917.

Abstract:
Maxwell's equations comprise both electromagnetic and gravitational fields. The transverse part of the vector potential belongs to magnetism, the longitudinal one is concerned with gravitation. The Coulomb gauge indicates that longitudinal components of the fields propagate instantaneously. The delta-function singularity of the field of the divergence of the vector potential, referred to as the dilatation center, represents an elementary agent of gravitation. Viewing a particle as a source or a scattering center of the point dilatation, the Newton's gravitation law can be reproduced.

Abstract:
this is a brief summary with comments on selected contributions to the cosmology and gravitation section at the 24th brazilian meeting on particle and fields (enfpc xxiv), held at caxambu, from september 30 to october 4, 2003.

Abstract:
The photoeffect, (vacuum analogue of the photoelectric effect,) is used to study the structure of the physical vacuum, the outcome of which is the basis for an hypothesis on the nature of gravitation and inertia. The source of gravitation is the vacuum which has a weak massless elementary electrical dipole (+/-) charge. Inertia is the result of the elastic force of the vacuum in opposition to the accelerated motion of material objects. The vacuum is seen as the source of attraction for all bodies according to the law of induction.

Abstract:
The classical concept of "mass density" is not fundamental to the quantum theory of matter. Therefore, mass density cannot be the source of gravitation. Here, we treat electromagnetic energy, momentum, and stress as its source. The resulting theory predicts that the gravitational potential near any charged elementary particle is many orders of magnitude greater than the Newtonian value.

Abstract:
The physical basis of the standard theory of general relativity is examined and a nonlocal theory of accelerated observers is described that involves a natural generalization of the hypothesis of locality. The nonlocal theory is confronted with experiment via an indirect approach. The implications of the results for gravitation are briefly discussed.

Abstract:
We consider different deductions of the mysterious Weinberg formula and show that this leads us back to the model of fluctuational cosmology which correctly predicted in advance, dark energy driven, accelerating universe with a small cosmological constant. All this also provides us with an interpretation of Gravitation as the distributional effect of the residual energy of the universe.

Abstract:
Gravitation has posed a puzzle and a problem for many decades. Attempts to unify it with other fundamental interactions have failed. These problems and puzzles have been underscored by the likes of Witten and Weinberg. We survey this and argue that gravitation has a different character compared to other fundamental interactions - it is an energy distributed over all the elementary particles in the universe. The above puzzle and problem is resolved satisfactorily. These considerations lead to a varying $G$ cosmology consistent with observation. It is argued that apart from the usual tests, the above explains in addition the anomalous accelerations of the Pioneer spacecrafts. Further tests are also proposed.