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relativity

[rel-uh-tiv-i-tee] /ˌrɛl əˈtɪv ɪ ti/
noun
1.
the state or fact of being relative.
2.
Physics. a theory, formulated essentially by Albert Einstein, that all motion must be defined relative to a frame of reference and that space and time are relative, rather than absolute concepts: it consists of two principal parts. The theory dealing with uniform motion (special theory of relativity or special relativity) is based on the two postulates that physical laws have the same mathematical form when expressed in any inertial system, and the velocity of light is independent of the motion of its source and will have the same value when measured by observers moving with constant velocity with respect to each other. Derivable from these postulates are the conclusions that there can be no motion at a speed greater than that of light in a vacuum, mass increases as velocity increases, mass and energy are equivalent, and time is dependent on the relative motion of an observer measuring the time. The theory dealing with gravity (general theory of relativity or general relativity) is based on the postulate that the local effects of a gravitational field and of acceleration of an inertial system are identical.
3.
dependence of a mental state or process upon the nature of the human mind:
relativity of values; relativity of knowledge.
Origin
1825-1835
1825-35; relative + -ity
Related forms
nonrelativity, noun
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
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Examples from the web for relativity
  • He also added the earliest concepts of relativity and the concept of infinity.
  • The ingredients are of secondary importance, and always in a divine relativity.
  • No matter who tries to spin them, they do not lie when their reality of relativity is shown.
  • Examines the physics behind the mathematical formalism of the theory of relativity.
  • These tragic news events remind all of us about the relativity and uncertainty of our safety.
  • Known for his theory of relativity, this scientist was also a fashionista, patenting a suit jacket that adjusts with your weight.
  • relativity places an important practical limit on this because some experiments would fall outside the causal horizon of others.
  • There is no paradox, and if you believe that there is, then you clearly do not understand the accepted theory of relativity.
  • The quote is not related to the theory of relativity.
  • They don't need to know that anymore than they need to understand relativity, string theory or the chaos theory of the universe.
British Dictionary definitions for relativity

relativity

/ˌrɛləˈtɪvɪtɪ/
noun
1.
either of two theories developed by Albert Einstein, the special theory of relativity, which requires that the laws of physics shall be the same as seen by any two different observers in uniform relative motion, and the general theory of relativity which considers observers with relative acceleration and leads to a theory of gravitation
2.
(philosophy) dependence upon some variable factor such as the psychological, social, or environmental context See relativism
3.
the state or quality of being relative
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for relativity
n.

1834, "fact or condition of being relative" (apparently coined by Coleridge, of God, in "Notes on Waterland's Vindication of Christ's Divinity"), from relative (adj.) + -ity. In scientific use, connected to the theory of Albert Einstein (1879-1955), published 1905 (special theory of relativity) and 1915 (general theory of relativity), but the word was used in roughly this sense by J.C. Maxwell in 1876.

Online Etymology Dictionary, © 2010 Douglas Harper
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relativity in Science
relativity
  (rěl'ə-tĭv'ĭ-tē)   
Either of two theories in physics developed by Albert Einstein, General Relativity or Special Relativity. See Notes at Einstein, gravity, space-time.

relativistic adjective
Our Living Language  : Albert Einstein's two theories of relativity were the first successful revisions of Newtonian mechanics—a mechanics so simple and intuitive that it was held to be a permanent fixture of physics. Uniting the theories is the idea that two observers traveling relative to each other may have different perceptions of time and space, yet the laws of nature are still uniform, and certain properties always remain invariant. Einstein developed the first theory, the theory of Special Relativity (1905), to explain and extend certain consequences of Maxwell's equations describing electromagnetism, in particular, addressing a puzzle surrounding the speed of light in a vacuum, which was predicted always to be the same, whether the light source is stationary or moving. Special Relativity considers the laws of nature from the point of view of frames of reference upon which no forces are acting, and describes the way time, distance, mass, and energy must be perceived by observers who are in uniform motion relative to each other if the speed of light must always turn out the same for all observers. Two implications of Special Relativity are space and time dilation. As speed increases, space is compressed in the direction of the motion, and time slows down. A famous example is the space traveler who returns to Earth younger than his Earth-dwelling twin, his biological processes proceeding more slowly due to his relative speed. These effects are very small at the speeds we normally experience but become significant at speeds approaching the speed of light (known as relativistic speeds). Perhaps the best-known implication of Special Relativity is the equation E=mc2, which expresses a close relation between energy and mass. The speed of light is a large number (about 300,000 km per second, or 186,000 mi per second), so the equation suggests that even small amounts of mass can be converted into enormous amounts of energy, a fact exploited by atomic power and weaponry. Einstein's General Theory of relativity extended his Special Theory to include non-inertial reference frames, frames acted on by forces and undergoing acceleration, as in cases involving gravity. The General Theory revolutionized the way gravity, too, was understood. Since Einstein, gravity is seen as a curvature in space-time itself.

The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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relativity in Culture

relativity definition


A theory concerning time, space, and the motion of objects, proposed first in 1905 by Albert Einstein in his special theory of relativity.

The “special theory of relativity” is based on the principle of special relativity, which states that all observers moving at constant velocities with respect to each other should find the same laws of nature operating in their frames of reference. It follows from this principle that the speed of light would have to appear to be the same to every observer. The theory predicts that moving clocks will appear to run slower than stationary ones (see time dilation), that moving objects will appear shorter and heavier than stationary ones, and that energy and mass are equivalent (see E = mc2). There is abundant experimental confirmation of these predictions.

The general theory of relativity is the modern theory of gravitation, proposed in 1915, also by Albert Einstein. The central point of the theory is the principle of general relativity, which states that all observers, regardless of their state of motion, will see the same laws of physics operating in the universe. The most famous prediction of the theory is that light rays passing near the sun will be bent — a prediction that has been well verified.

Note: The special and general theories of relativity have had important implications for thought in general. They show that no frame of reference for observation of nature is more correct than any other.
Note: It is important to distinguish between the theory of relativity, in which the laws of nature are the same for all observers anywhere in the universe, and the philosophical doctrine of relativism, which holds that there are no absolute truths. The similarity in their names has been a source of confusion.
The American Heritage® New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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