Gravity is a force of attraction that acts between bodies that have mass. It is a physical phenomenon of fundamental importance, profoundly affecting the workings of the world around us and the universe beyond. Most familiarly, it is the gravitational attraction of the earth that endows objects with weight and causes them to fall to the ground when dropped. In fact, gravity is also the reason for the very existence of the earth, the sun and other celestial bodies; without it matter would not have coalesced into these bodies and ...

Including:

• Gravity - Overview of the history of gravitational theory
• Gravity - Newton's law of universal gravitation
• Gravity - Acceleration due to gravity
• Gravity - Bodies with spatial extent
• Gravity - Vector form
• Gravity - Gravitational field
• Gravity - The Earth's gravity
• Gravity - Comparative gravities of the Earth Sun Moon and planets
• Gravity - Mathematical equations for a falling body
• Gravity - Gravitational potential
• Gravity - Acceleration relative to the rotating Earth
• Gravity - Gravity and astronomy
• Gravity - Self-gravitating system
• Gravity - Practical uses of gravity
• Gravity - Problems with Newton's theory
• Gravity - Theoretical concerns
• Gravity - Disagreement with observation
• Gravity - Newton's reservations
• Gravity - Einstein's theory of gravitation
• Gravity - Experimental tests
• Gravity - Comparison with electromagnetic force
• Gravity - Gravity and quantum mechanics
• Gravity - Alternative theories
• Gravity - Recent alternative theories
• Gravity - Historical alternative theories
• Gravity - Notes

Read more here: » Gravity: Encyclopedia - Gravity

See also:

Gravity, Gravity - Overview of the history of gravitational theory, Gravity - Newton's law of universal gravitation, Gravity - Acceleration due to gravity, Gravity - Bodies with spatial extent, Gravity - Vector form, Gravity - Gravitational field, Gravity - The Earth's gravity, Gravity - Comparative gravities of the Earth Sun Moon and planets, Gravity - Mathematical equations for a falling body, Gravity - Gravitational potential, Gravity - Acceleration relative to the rotating Earth, Gravity - Gravity and astronomy, Gravity - Self-gravitating system, Gravity - Practical uses of gravity, Gravity - Problems with Newton's theory, Gravity - Theoretical concerns, Gravity - Disagreement with observation, Gravity - Newton's reservations, Gravity - Einstein's theory of gravitation, Gravity - Experimental tests, Gravity - Comparison with electromagnetic force, Gravity - Gravity and quantum mechanics, Gravity - Alternative theories, Gravity - Recent alternative theories, Gravity - Historical alternative theories, Gravity - Notes

Read more here: » Gravity: Encyclopedia II - Gravity - Gravity and astronomy

So Newton's original formula was: where the symbol means "is proportional to". To make this into an equal-sided formula or equation, there needed to be a multiplying factor or constant that would give the correct force of gravity no matter the value of the masses or distance between them. This gravitational constant was discovered in 1797 by Henry Cavendish. Thus the discovery and application of Newton's law of gravity accounts for the detailed information we have about the planets in our sol ...

See also:

Gravity, Gravity - Overview of the history of gravitational theory, Gravity - The Earth's gravity, Gravity - Comparative gravities of the Earth Sun Moon and planets, Gravity - Mathematical equations for a falling body, Gravity - Gravitational potential, Gravity - Acceleration relative to the rotating Earth, Gravity - Gravity and astronomy, Gravity - Self-gravitating system, Gravity - Practical uses of gravity, Gravity - Newton's law of universal gravitation, Gravity - Acceleration due to gravity, Gravity - Bodies with spatial extent, Gravity - Vector form, Gravity - Gravitational field, Gravity - Problems with Newton's theory, Gravity - Theoretical concerns, Gravity - Disagreement with observation, Gravity - Newton's reservations, Gravity - Einstein's theory of gravitation, Gravity - Experimental tests, Gravity - Comparison with electromagnetic force, Gravity - Gravity and quantum mechanics, Gravity - Alternative theories, Gravity - Recent alternative theories, Gravity - Historical alternative theories, Gravity - Notes

Read more here: » Gravity: Encyclopedia II - Gravity - Gravity and astronomy

When a row of blocks is cleared and removed, the stacks of blocks above it fall. Traditional versions of Tetris move the stacks of blocks down by a distance exactly equal to the height of the cleared rows below them. Unlike Newtonian gravity, blocks may be left floating above gaps. This behavior is known as "naive gravity." Some variants implement a different algorithm that uses a flood fill to segment the playfield into connected regions and then makes each region fall individually, in parallel, until it touches the region at ...

See also:

Tetris, Tetris - The game, Tetris - Gravity, Tetris - History and legal issues, Tetris - Scoring formula, Tetris - Modes of Play and Feature Deviations, Tetris - Newest feature additions, Tetris - Tetris variants, Tetris - Is it possible to play forever?, Tetris - Music, Tetris - Notes

Read more here: » Tetris: Encyclopedia II - Tetris - Gravity

Action at a distance physics - Newton. Newton's theory of gravity offered no prospect of identifying any mediator of gravitational interaction. His theory assumed that gravitation acts instantaneously, regardless of distance. Newton had shown mathematically that if the gravitational interaction is not instantaneous, angular momentum is not conserved, and Kepler's observations gave strong evidence that in planetary motion angular momentum is conserved. (The mathematical ...

See also:

Action at a distance physics, Action at a distance physics - Electricity, Action at a distance physics - Gravity, Action at a distance physics - Newton, Action at a distance physics - Einstein, Action at a distance physics - Quantum mechanics

Read more here: » Action at a distance physics: Encyclopedia II - Action at a distance physics - Gravity

The first mathematical formulation of gravity was Isaac Newton's law of universal gravitation, published in his 1687 work Principia Mathematica. Professor William Whewell of Cambridge University, author of History of the Inductive Sciences (1837) stated: "The law of gravitation is indisputably and incomparably the greatest scientific discovery ever made, whether we look at the advance which it involved, the extent of the truth disclosed, or the fundamental and satisfactory nature of this truth." [In A Treasury o ...

See also:

Gravity, Gravity - Overview of the history of gravitational theory, Gravity - Newton's law of universal gravitation, Gravity - Acceleration due to gravity, Gravity - Bodies with spatial extent, Gravity - Vector form, Gravity - Gravitational field, Gravity - The Earth's gravity, Gravity - Comparative gravities of the Earth Sun Moon and planets, Gravity - Mathematical equations for a falling body, Gravity - Gravitational potential, Gravity - Acceleration relative to the rotating Earth, Gravity - Gravity and astronomy, Gravity - Self-gravitating system, Gravity - Practical uses of gravity, Gravity - Problems with Newton's theory, Gravity - Theoretical concerns, Gravity - Disagreement with observation, Gravity - Newton's reservations, Gravity - Einstein's theory of gravitation, Gravity - Experimental tests, Gravity - Comparison with electromagnetic force, Gravity - Gravity and quantum mechanics, Gravity - Alternative theories, Gravity - Recent alternative theories, Gravity - Historical alternative theories, Gravity - Notes

Read more here: » Gravity: Encyclopedia II - Gravity - Overview of the history of gravitational theory

The first mathematical formulation of gravity was Isaac Newton's law of universal gravitation, published in his 1687 work Principia Mathematica. Professor William Whewell of Cambridge University, author of History of the Inductive Sciences (1837) stated: "The law of gravitation is indisputably and incomparably the greatest scientific discovery ever made, whether we look at the advance which it involved, the extent of the truth disclosed, or the fundamental and satisfactory nature of this truth." [In A Treasury o ...

See also:

Gravity, Gravity - Overview of the history of gravitational theory, Gravity - The Earth's gravity, Gravity - Comparative gravities of the Earth Sun Moon and planets, Gravity - Mathematical equations for a falling body, Gravity - Gravitational potential, Gravity - Acceleration relative to the rotating Earth, Gravity - Gravity and astronomy, Gravity - Self-gravitating system, Gravity - Practical uses of gravity, Gravity - Newton's law of universal gravitation, Gravity - Acceleration due to gravity, Gravity - Bodies with spatial extent, Gravity - Vector form, Gravity - Gravitational field, Gravity - Problems with Newton's theory, Gravity - Theoretical concerns, Gravity - Disagreement with observation, Gravity - Newton's reservations, Gravity - Einstein's theory of gravitation, Gravity - Experimental tests, Gravity - Comparison with electromagnetic force, Gravity - Gravity and quantum mechanics, Gravity - Alternative theories, Gravity - Recent alternative theories, Gravity - Historical alternative theories, Gravity - Notes

Read more here: » Gravity: Encyclopedia II - Gravity - Overview of the history of gravitational theory

In physics, the center of gravity (CG) of an object is a point at which the object's mass can be assumed, for many purposes, to be concentrated. For example, if you hang an object from a string, the object's center of gravity will be directly below the string. The path of an object in orbit depends only on its center of gravity. In objects that are radially symmetric, both the center of gravity and the center of mass coincide. The center of gravity of an object is the average location of its weight. In a uniform gravitation ...

Including:

• Center of gravity - Centers of gravity of simple objects
• Center of gravity - Locating Center of Gravity 1
• Center of gravity - Locating Center of Gravity 2
• Center of gravity - Similarities between center of mass and center of inertia
• Center of gravity - Differences between center of mass and center of inertia

Read more here: » Center of gravity: Encyclopedia - Center of gravity

The Aristotelian theory of gravity was that all bodies move towards their natural place. For some objects, Aristotle claimed the natural place to be the center of the earth, wherefore they fall towards it. For other objects, the natural place is the heavenly spheres, wherefore gases, steam for example, move away from the center of the earth and towards heaven and to the moon. The speed of th ...

Read more here: » Aristotelian theory of gravity: Encyclopedia - Aristotelian theory of gravity

API Gravity is a specific gravity scale developed by the American Petroleum Institute (API) for measuring the relative density of various petroleum liquids. API gravity is gradated in degrees on a hydrometer instrument and was designed so that most values would fall between 10 and 70 API gravity degrees. The U.S. National Bureau of Standards established the Baumé scale (see degrees Baumé) as the standard for measuring specific gravity of liquids less dense than water in 1916. Investigation by the U.S. National A ...

Read more here: » API gravity: Encyclopedia - API gravity

Anti-gravity is a hypothetical means of countering or otherwise modifying the effects of gravity, typically in the context of spacecraft propulsion. Such systems are limited to the realm of science fiction given the current understanding of the way gravity works, but this has not stopped legions of hopefuls from making various spinning disks and magnets in hopes of perfecting such a device. Anti-gravity - Anti-gravity in the context of mainstream physics. Newton's Law of Gravitation cons ...

Including:

• Anti-gravity - Anti-gravity in the context of mainstream physics
• Anti-gravity - Conventional effects that look like anti-gravity
• Anti-gravity - Anti-gravity in the context of non-mainstream physics

Read more here: » Anti-gravity: Encyclopedia - Anti-gravity

Artificial gravity could be created in several ways: Artificial gravity - Rotation. The spacecraft could rotate so that anything inside will be forced toward the outside by centrifugal force. Artificial gravity by rotation has the following side effects: Coriolis forces produced by rotation could cause dizziness, nausea and disorientation. Experiments have shown that slower rates of rotation reduce the Coriolis forces and its effects. It is generally believed that at 2 rpm or less no adverse e ...

See also:

Artificial gravity, Artificial gravity - Methods, Artificial gravity - Rotation, Artificial gravity - Acceleration, Artificial gravity - Mass, Artificial gravity - Tidal forces, Artificial gravity - Magnetism, Artificial gravity - Fiction, Artificial gravity - Rotational Gravity, Artificial gravity - Field generators

Read more here: » Artificial gravity: Encyclopedia II - Artificial gravity - Methods

If two bodies are rigidly fixed to each other, then the center of gravity of the combination lies on the line joining the centers of gravity of the individual bodies. In symmetric bodies, the CG lies on the line of symmetry. If there are two or more lines of symmetry, then the CG is at the point of intersection of these lines. The CG of a rectangle is at the intersection of the two diagonals. This principle is used in the example given below. The CG of a triangle lies on the median (line joining the vertex to the mid-point of the opposite side ...

See also:

Center of gravity, Center of gravity - Centers of gravity of simple objects, Center of gravity - Locating center of gravity 1, Center of gravity - Locating center of gravity 2, Center of gravity - Similarities between center of mass and center of inertia, Center of gravity - Differences between center of mass and center of inertia

Read more here: » Center of gravity: Encyclopedia II - Center of gravity - Centers of gravity of simple objects

There are a number of proposed quantum gravity theories: String theory/superstring theory/M-theory Supergravity AdS/CFT Wheeler-deWitt equation Loop quantum gravity Euclidean quantum gravity Noncommutative geometry Twistor theory Discrete Lorentzian quantum gravity Sakharov induced gravity Regge calculus acoustic metric and other analog model ...

See also:

Quantum gravity, Quantum gravity - Overview, Quantum gravity - Historical perspective, Quantum gravity - The incompatibility of quantum mechanics and general relativity, Quantum gravity - Theories, Quantum gravity - Weinberg-Witten theorem, Quantum gravity - Quantum gravity theorists, Quantum gravity - In Popular Culture

Read more here: » Quantum gravity: Encyclopedia II - Quantum gravity - Theories

If two bodies are rigidly fixed to each other, then the center of gravity of the combination lies on the line joining the centers of gravity of the individual bodies. In symmetric bodies, the CG lies on the line of symmetry. If there are two or more lines of symmetry, then the CG is at the point of intersection of these lines. The CG of a rectangle is at the intersection of the two diagonals. This principle is used in the example given below. The CG of a triangle lies on the median (line joining the vertex to the mid-point of the opposite side ...

See also:

Center of gravity, Center of gravity - Centers of gravity of simple objects, Center of gravity - Locating Center of Gravity 1, Center of gravity - Locating Center of Gravity 2, Center of gravity - Similarities between center of mass and center of inertia, Center of gravity - Differences between center of mass and center of inertia

Read more here: » Center of gravity: Encyclopedia II - Center of gravity - Centers of gravity of simple objects

In linearised gravity, the metric tensor of spacetime g is treated as a sum of a solution of Einstein's equations (usually the Minkowksi metric) and a perturbation h. where η is the nondynamical background metric that we are perturbing about and h represents the deviation of the true metric (g) from flat spacetime. The perturbation is treated using the methods of perturbation theory. The adjective "linearized" means that all terms of order higher than one (quadratic in h, cu ...

See also:

Linearized gravity, Linearized gravity - The method, Linearized gravity - Applications

Read more here: » Linearized gravity: Encyclopedia II - Linearized gravity - The method

A simple experiment to locate the center of gravity of a "2-D" object: You will need: 1) A roughly cut piece of cardboard [lamina](for best results just tear a piece of carboard off) 2) Some string 3) A weight of some sort (not very heavy, but heavy enough to hold string down) 4) A punch (or some sort of device which can be used to puncture a hole in the carboard) 5) 2 pencils 6) Scissors with which t ...

See also:

Center of gravity, Center of gravity - Centers of gravity of simple objects, Center of gravity - Locating Center of Gravity 1, Center of gravity - Locating Center of Gravity 2, Center of gravity - Similarities between center of mass and center of inertia, Center of gravity - Differences between center of mass and center of inertia

Read more here: » Center of gravity: Encyclopedia II - Center of gravity - Locating Center of Gravity 1

Gravity's Rainbow is available in paperback under ISBN 0140188592 and ISBN 0140283382. Also available is Steven C. Weisenburger's A Gravity's Rainbow Companion: Sources and Contexts for Pynchon's Novel which documents many the references and allusions used by Pynchon for his novel. ISBN 0820310263 ...

See also:

Gravity's Rainbow, Gravity's Rainbow - Structure and chronology, Gravity's Rainbow - Plot, Gravity's Rainbow - Relation to actual wartime events, Gravity's Rainbow - Public reaction, Gravity's Rainbow - Availability

Read more here: » Gravity's Rainbow: Encyclopedia II - Gravity's Rainbow - Availability

Much of the difficulty in merging these theories comes from the radically different assumptions that these theories make on how the universe works. Quantum field theory depends on particle fields embedded in the flat space-time of special relativity. General relativity models gravity as a curvature within space-time that changes as mass moves. The most obvious ways of combining the two (such as treating gravity as simply another particle field) run quickly into what is known as the renormalization problem. Gravity particles would attract eac ...

See also:

Quantum gravity, Quantum gravity - Overview, Quantum gravity - Historical perspective, Quantum gravity - The incompatibility of quantum mechanics and general relativity, Quantum gravity - Theories, Quantum gravity - Weinberg-Witten theorem, Quantum gravity - Quantum gravity theorists, Quantum gravity - In Popular Culture

Read more here: » Quantum gravity: Encyclopedia II - Quantum gravity - Overview

It is often difficult to follow the plot and direction of Gravity's Rainbow, particularly as a main plot line does not emerge until the second part of the book; the lengthy first part effectively acts as an introduction. The plot is complex, involving the V-2 rocket and Operation Paperclip, IG Farben, Standard Oil, parapsychology, behaviorism, psychology theory (Ivan Pavlov's experiments concerning conditioning especially), and conspiracy theories, such as the Phoebus cartel and the Illuminati. Gravity's Rainbow also dra ...

See also:

Gravity's Rainbow, Gravity's Rainbow - Structure and chronology, Gravity's Rainbow - Plot, Gravity's Rainbow - Relation to actual wartime events, Gravity's Rainbow - Public reaction, Gravity's Rainbow - Availability

Read more here: » Gravity's Rainbow: Encyclopedia II - Gravity's Rainbow - Plot