Gravitation
 Although we have many theories on gravitation, we are far from understanding its cause or mechanism of its actions. Contemporary theories deal with only a small part of gravitation - the (apparent) gravitational attraction between matter-bodies. Arguments of these theories are based on the worst assumption in science - 'the action at a distance' through empty space. Since 'action at a distance' is irrational, most conjectures about the cause and mechanism of actions of gravitation are also illogical. 'Hypothesis on MATTER' is an alternative concept that provides logical explanations to all physical phenomena of matter. It has no 'actions at a distance'. There is only one type of matter particles, postulated in this concept. These matter particles, in turn, produce everything else in this universe, including gravitation. Gravitation is much more than mere (apparent) attraction between matter-bodies. (Apparent) attraction between matter-bodies is relatively a minor aspect of gravitation. 'Hypothesis on MATTER' provides definite cause and specific mechanism for gravitational actions. Gravitation is the originator of all other actions in nature. All natural forces are derived from it. Various natural forces are nothing but different manifestations of only one type of 'force' in nature. Gravitational actions create and sustain three-dimensional matter particles and macro bodies, constituted by them. Gravitation develops and sustains the universe, as we observe it. While accepting existing theories, even though we knew them to be perfectly irrational, we had no hesitation to accept many assumptions like; 'actions at a distance', 'instantaneous action of gravitation, 'mass-less particles like gravitons', etc. to understand the phenomenon of gravitation. We bear with far too many assumptions, on which contemporary theories are based. Yet they do not give us a comprehensive theory of gravitation, encompassing all actions under all conditions. Hence, I request the reader to bear with the assumption of only one type of matter particles for the development of a comprehensive theory that can logically explain all phenomena related to matter, under all conditions, by the same basic laws. There is no singularity in nature, when physical laws are invalid. Applications of physical laws are identical at all places and under all conditions. Since the book 'Hypothesis on MATTER' deals with all phenomena related to matter, it is brief in details and very elaborate in contents for those who are interested only in certain phenomenon. This book 'Gravitation' is compiled from explanations given in the book, 'Hypothesis on MATTER'. Only those details, directly pertaining to gravitation are included here. Other conclusions, reflected in this book, are from the parent book. Reader may kindly refer to the same for details of mechanisms of various phenomena, omitted in this book.

 Chapter 1. INTRODUCTION
 1.1. Perspective of Gravitation 1.2. Hypothesis on MATTER

 Chapter 2. 2D ENERGY FIELDS
 Chapter 2 briefly describes perspective and development of a logical universal medium . An elementary matter particle, 'quantum of matter', that has positive existence in space and has definite properties is postulated. Other than for the quanta of matter and their properties, no other imaginary particles or assumed properties are used. All actions in nature are originated (ultimately) from the action of quanta of matter. All actions are results of definite causes, which precede them. No action at a distance is envisaged. Quanta of matter form latticework structures of 2D energy fields in space. Everything in the universe is created from and by the 2D energy fields. 2D energy fields are the media of all actions. 2D energy fields, in this concept, replace the all-encompassing 'aether' in the aether theories. Unlike the aether, the 2D energy fields have definite constituents, existence in space, structure, properties and ability to act. Due to the inherent property of 2D energy fields, to maintain their continuity and serenity, a discontinuity in the 2D energy fields causes the gravitational effects.
 2.1. Space: 2.1.1. Aether drag: 2.1.2. Perspective of Universal medium: 2.2. Quantum of Matter: 2.2.1. Properties of quanta of matter: 2.2.2. Formation of junction points: 2.3. 2D energy field: 2.3.1. Reaction: 2.3.2. Work and force: 2.3.3. Self-sustenance of 2D energy field: 2.3.4. Field force: 2.3.5. Stabilization of 2D energy field: 2.3.6. Equilibrium of 2D energy field: 2.3.7. Properties of 2D energy fields: 2.4. Production of a Disturbance: 2.4.1. Development of a disturbance: 2.4.2. Magnitude of a disturbance:
 Chapter 3. GRAVITATION IN 2D SPACE
 Gravitational actions are proportional to the extent of 2D energy fields, producing the gravitational actions and they are of push nature. Gravitational actions have definite nature and limitations. Gravitation is ineffective on straight perimeters of matter particles. Greater gravitational actions from the outer (curved) sides of two 3D matter particles (compared to lower gravitational actions from in between them) cause apparent attraction due to gravity between the two matter particles.
 3.1. Gravitation: 3.1.1. Range of gravitation: 3.1.2. Nature of gravitation: 3.1.3. Strength of gravitation: 3.1.4. Gravitation on a point-disturbance: 3.2. Gravitation on a 2D disturbance: 3.2.1. Shaping up a disturbance: 3.2.2. Application of gravitation: 3.3. Action of gravitation: 3.3.1. Motion of a particle by gravitation: 3.3.2. Pressure energy of a disturbance: 3.3.3. Gravitation on a straight perimeter: 3.3.4. Gravitation on a curved perimeter: 3.4. Apparent gravitational attraction: 3.4.1. Magnitude of apparent gravitational attraction: 3.4.2. Effect of angle subtended: 3.4.3. Many bodies in the same plane:
 Chapter 4. CREATION OF 3D MATTER
 Free quanta of matter, within a gap in the 2D energy fields are gathered and compressed by gravitational action to create a 2D disturbance. Gravitational pressure on larger 2D disturbances converts them into real 3D matter. Photons, the corpuscles of light, are disc shaped matter bodies, moving at constant linear speeds and spinning at speeds proportional to their matter contents. Associated energy of a photon is invested in the 2D energy fields about its matter body in the form of strain in the distorted latticework structure of 2D energy fields. Inertia is a property of 2D energy fields. Actions are simple mechanical movements of quanta in the latticework structures of 2D energy fields. Strain, produced due to the distortions in the 2D energy fields is the energy stored. Characteristic properties of various types of motions are determined by the structure of 2D energy fields. Matter field of a body is the distorted part of 2D energy fields in and about the body limits.
 4.1. Size reduction of a disturbance: 4.1.1. Contraction of a small disturbance: 4.1.2. Contraction of larger disturbance: 4.1.3. Internal pressure of a disturbance: 4.1.4. Very large disturbance: 4.1.5. Disturbance of optimum size: 4.2. Creation of three-dimensional matter: 4.2.1. Creation of higher-dimensional matter: 4.2.2. Critical radial size of a 3D disturbance: 4.2.3. Shaping up of a 3D disturbance: 4.3. Development of 3D matter particle: 4.3.1. Ejection force: 4.3.2. Spinning force: 4.3.3. Ejection and spin of a disturbance: 4.3.4. Centrifugal force in a disturbance: 4.4. Photon: 4.4.1. Shape of a photon: 4.4.2. Concepts of a photon: 4.5. Distortion fields: 4.5.1. Linear distortion field: 4.5.2. Angular distortion field: 4.5.3. Radial distortion field: 4.6. Macro Bodies: 4.6.1. Matter field: 4.6.2. Motion of macro bodies: 4.6.3. Inertia of rotary motion: 4.6.4. Motion due to torque:            Action of a rotating force:            Action of linear force on rotating body:
 Chapter 5. GRAVITATION IN 3D SPACE
 Independent gravitational actions in many 2D energy fields, together form gravitational actions in 3D space system. Practical gravitational constant in 3D space system is only a very small fraction of its real value. Gravitational effort is enormously stronger than other manifestations of forces. Practically, gravitational forces appears to be weak because only a very small number of 3D matter particles in two macro bodies produce apparent gravitational attraction between them, at any instant. Gravitational actions are between each 3D matter body (particle) and surrounding 2D energy fields. This makes the development of apparent attraction due to gravity between two bodies, instantaneous. No transfer of imaginary particles or action at a distance is required to explain the instantaneous development of apparent attraction due to gravity, however far the bodies may be.
 5.1. Gravitation in 3D space: 5.1.1. Apparent gravitational attraction in 3D space: 5.1.2. Push gravitation: 5.1.3. Gravitational attraction between photons:            Gravitational attraction between coplanar photons: 5.1.4. Macro bodies' apparent gravitational attraction: 5.1.5. Magnitude of apparent gravitational attraction: 5.2. 3D system's gravitational constant in 2D system: 5.2.1. Practical gravitational constant: 5.3. Action at a distance: 5.4. Screening the gravitation: 5.4.1. Levitation:
 Chapter 6. MAGNITUDE OF ATTRACTION
 Magnitude of gravitational attraction is determined by inertial action it can produce on macro bodies. Inverse square law, used to determine magnitude of gravitational attraction has its limitations. Irrespective of various methods used to prevent its breakdown, it may breakdown under certain conditions. most of the anomalies, noticed during measurement of gravitational actions are due to improper use of this equation.
 6.1. Centre of gravity: 6.1.1. Inverse square law: 6.1.2. Breakdown of inverse square law: 6.2. Anomalies in gravitational attraction: 6.3. Mass and weight: 6.3.1. Mass of a body: 6.3.2. Weight of a body: 6.3.3. Matter contents of fundamental particles:
 Chapter 7. GENERAL
 Chapter seven explains some of the practical applications of gravitational attraction in nature.
 7.1. Aether drag: 7.2. Heat and gravitation: 7.2.1. Heating: 7.2.2. Acceleration due to external force: 7.2.3. Acceleration due to gravity: 7.3. Central force: 7.3.1. Magnitude of radial velocity: 7.4. Planetary orbits: 7.4.1. Linear motion of a rotating body: 7.4.2. Orbital motion:            Inner solar System: 7.4.3. Circular orbit: 7.4.4. Elliptical Orbit:            Limits of angular speed during entry:            Orbits about a moving central body: 7.4.5. Anomalies in planetary orbits:            Apparent loss of orbital motion of a planet:            Precession due to eccentricity:            Precession due to central body's path:            Perturbations caused by collisions: 7.4.6. Electronic orbits: 7.5. Planetary spin: 7.5.1. Spin due to central force: 7.5.2. Unequal spin motion of a planetary body: 7.5.3. Apparent spin motion: 7.5.4. Anomalies: 7.5.5. Variations in a terrestrial day: 7.6. Tides: 7.6.1. Terrestrial tides: 7.6.2. Direction of tides:            Magnitude of angular shift:            Direction of angular shift:            Direction of Solar tides:            Direction of lunar tides:            Effect of orbital motion on direction of tides: 7.7. Galactic repulsion: 7.8. Gravitational collapse of large bodies: