|Contemporary theories on gravitation, deal only with its dynamic actions on 3D matter-bodies. Dynamic actions due to gravitation are continuation of its actions on static matter-bodies. Static part of gravitational action is usually ignored in most theories on gravitation. Hence, gravitation is generally understood as a force (trying to or) moving a three-dimensional macro matter-body towards another. There are no accepted theories on its basic nature or mechanism of its actions in general (or on static bodies). I hope the concept, put forward the book 'Hypothesis on MATTER' can fill this vacuum and provide logical description to the nature and mechanism of gravitation in its static and dynamical states. According to this concept, gravitational effort or manifestation of its (force) actions is enormously stronger, when compared to other manifestations of natural efforts or actions (forces). All natural actions have their origin in gravitational actions. (Apparent) attraction due to gravitation between three-dimensional matter-bodies (the only effect of gravitation, known to present-day science) is relatively a minor by-product of gravitation in nature.
Currently, natural forces are assumed to be of distinctly different types; gravitational, electromagnetic and (strong & weak) nuclear forces. In mechanics, gravitation is the assumed universal (apparent) attraction between matter-bodies. It is assumed a separate kind from other types of natural forces. Although the gravitational actions do much more, apparent attraction between matter-bodies is the only action currently attributed to gravitation. No cause or mechanism of action are postulated.
Primarily, real gravitational actions in nature; create, sustain and destroy basic 3D matter particles and superior matter-bodies in space, under appropriate conditions. Apparent attraction between matter-bodies is in fact a by-product of separate gravitational actions on different matter-bodies. Appearance of attraction between matter-bodies is the result of separate and simultaneous gravitational actions on the matter-bodies. Apparent gravitational attraction between matter-bodies is a very minute fraction of gravitational actions (forces) on these bodies. It is because of this, that the gravitational force is incorrectly assumed the weakest of all natural forces. Contrary to truth, gravitational force is assumed to play no role in determining the internal properties of everyday matter-bodies. However, due to its long reach and universality, gravitational actions are assumed to shape the structure and evolution of stars, galaxies and the entire universe. Laws of gravitation determine the trajectories of bodies in the solar and galactic systems.
Works of Isaac Newton and Albert Einstein dominate the development of current gravitational theories. Building on the works of many great men leading up to Galileo (Galilei) and Johannes Kepler, Isaac Newton developed the first quantitative theory of gravitation. Newton's classical theory of gravitational force held absolute sway until Einstein's work in the early 20th century. Even today, Newton's theory is of sufficient accuracy for all but the most precise applications. Newtonian theory of gravitation is based on an assumed force, acting between all pairs of matter-bodies through empty space, i.e., an action at a distance. When a matter-body (mass) moves or changes its parameters, this assumed force, acting on other matter-bodies has been considered to adjust instantaneously to the new location of the displaced body and change its magnitude corresponding to the present parameters of matter-bodies. Without giving any reasons or mechanism of action, Newton held that every particle of matter in the universe attracts every other particle with a force that is proportional to the product of their masses (representing their matter contents) and inversely proportional to the square of distance between their centers (of gravity). This assumption was the result of observation of nature. Newton (or any other scientist) provided no reason or logical explanation for such (assumed) attraction between matter-bodies across empty space. This assumption formed the basis of all further developments of theories on gravitation.
Another assumption, prevailing at that time (and even today) is that planets orbit around their central bodies. This assumption played a crucial role in establishing the current theories on gravitation. It is from these closed geometrical figures of planetary orbits around the central body that proofs of contemporary gravitational laws were derived. Since no free body (a free body is under no other influence other than the effort considered) can orbit in closed geometrical path around another moving body, above-given assumption is baseless. Newton was able to show Kepler's three empirical laws of planetary motion mathematically, from his own three general laws of motion and the above mentioned law of gravitation. Power of these laws to explain and predict various phenomena were confirmed later. This made Newton's laws of gravitation infallible truths of science, all the while forgetting that the mathematical treatments used for the purpose are the (observed paths) apparent planetary orbital motions around a central body and not the true orbital paths of the planets about their central body.
We must consider that Kepler's laws of planetary motions were formulated at a time, when the phenomenon of gravitation or central force between earth and sun were unknown. What Kepler has done is to formulate laws to suite the observed locations of planets about the sun, which was considered to be static in space. No interactions or forces between central body and the planets were even considered as a cause of these relative motions of planets. Moreover, orbital path of moon was discarded. Probably, due to the realization that the moon could not execute an elliptical orbit around the moving earth. His laws are applicable only to the observed orbits of planets around a (static) sun. Despite these facts, Kepler's laws on planetary motion are routinely used in conjunction with many types of multi-body problems. Although mathematical treatments of apparent actions may produce results, which suit apparent phenomena, they cannot describe real facts.
Another but similar assumption is about the cause and nature of terrestrial tides. In mechanics, two forces acting on a body produce a single resultant action on the body. Yet two separate central forces on earth cause two separate and simultaneous sets of tides on earth. Smaller central force due to the moon causes larger set of tides, while greater central force towards the sun causes smaller set of tides. None of the exotic theories, formulated to justify these anomalies is logical. Centre of gravity of a macro body is an important assumption in Newtonian gravitational theory. Each macro body has a single centre of gravity. If more than one center of gravity is assigned to a single macro body, it is corrupting the phenomenon of centre of gravity. It is not correct to assume that an external macro body can gravitationally interact with different parts of a macro body, differently, as is considered in explanations on terrestrial tides.
Though, theoretically, vector equations in Newton's theory of gravitation could be used for finding the resulting gravitational field, when used for irregular non-spherical macro bodies, these equations are inefficient. In order to overcome this difficulty, potential theory was developed by scientists to deal with mysterious gravitational fields, mathematically. Potential theory led to the formulation of gravitational acceleration at any point in space called the gravitational potential. These are very useful in mathematical operations. However, at present, no one has clear understanding of what is a gravitational field.
Newton's conception and quantification of gravitation held absolute until the notion of instantaneous action at a distance (and through empty space), which his concept entailed, was recognized generally as unintelligible and illogical. In his general theory of relativity, Albert Einstein developed a wholly new concept of gravitation. Einstein proposed the idea of four-dimensional space-time continuum, which is curved by the presence of matter. This concept produces a universe in which bodies travel in geodesics (shortest paths). Geodesics replace the curved planetary orbits interpreted by Newton, as the result of some attractive force. Even in this case the planetary orbital paths are considered as closed geometrical figures around central bodies. Structure of space or the ability of a form-less space to bend or the mechanism of its wrap are not explained. Instead, non-physical space is assumed to possess physical characteristics to suit the theory.
Both, the above theories, rely heavily on the elliptical nature of planetary orbits around central bodies for their validity. Elliptical or circular natures of planetary orbital path are relative or apparent paths, as observed about the planets and their central bodies by observers on them. Kepler's laws of planetary motion are with respect to imaginary orbital paths of planets around a central body. Theories, based on imaginary concepts cannot be true. These theories also do not provide any explanations to the instantaneous nature of gravitational action or logically explain the mechanism of actions at a distance.
Special relativity theory considers that no physical signal travels faster than the speed of light and that all signals travel at this speed through empty space. No reason as to why or how they do so is given. Special relativity theory, with the field theories of electrical and magnetic phenomena, has met with much empirical success that most modern gravitational theories are constructed as field theories, consistent with the principles of special relativity. In a field theory, it is assumed that mere presence of a macro body produces a gravitational field, which permeates all surrounding space and become weaker in strength as distance from the body increases. A second macro body within this gravitational field is then acted upon by its gravitational field and experiences a force. This Newtonian force is then viewed as the response by the first macro body to the gravitational field produced by the second macro body. However, there are no explanations on the structure, constituents or the mechanism of development of these 'gravitational' fields. Often, the space itself is assumed to replace these fields.
Predictions of several phenomena by the relativistic view of gravitation violate Newtonian theory of gravitation and to the limits of observational accuracy; they have been confirmed by various experiments. However, prediction of relativistic (gravitation) theory about the existence of gravity waves, propagated by objects (matter-bodies), moving in a gravitational field or any implied existence of gravitational particles are not confirmed or detected yet. Moreover, the relativity theory has no logical explanation to the instantaneous gravitational actions or to the 'actions at a distance', without numerous assumptions.
Contemporary gravitational theories do not acknowledge gravitational actions on static bodies. Force, which comes into existence only during motion, is its sole expression.