The noun has one meaning:
Meaning #1:
(physics) the theory that space and time are relative concepts rather than absolute concepts
Synonyms: relativity, relativity theory, Einstein's theory of relativity
Theory of relativity
| WordNet: theory of relativity |
| 5min Related Video: Theory of relativity |
| Wikipedia: Theory of relativity |
 |
This article includes a list of references, related reading or external links, but its sources remain unclear because it lacks inline citations. Please improve this article by introducing more precise citations where appropriate. (February 2008) |
- This page is about the scientific concept of relativity, for philosophical or sociological theories about relativity see Relativism.
The theory of relativity, or simply relativity, generally refers specifically to two theories of Albert Einstein: special relativity and general relativity. However, the word "relativity" is sometimes used in reference to Galilean invariance.
The term "theory of relativity" was coined by Max Planck in 1908 to emphasize how special relativity (and later, general relativity) uses the principle of relativity.
Contents |
Special relativity
Special relativity is a theory of the structure of spacetime. It was introduced in Albert Einstein's 1905 paper "On the Electrodynamics of Moving Bodies"; however, the term was first used by Galileo Galilei in 1632 in his Dialogue concerning the World's Two Chief Systems. But Galileo's version was flawed: for example, he thought the spin of the Earth caused the tides[1]. Special relativity is based on two postulates which are contradictory in classical mechanics:
- The laws of physics are the same for all observers in uniform motion relative to one another (Galileo's principle of relativity),
- The speed of light in a vacuum is the same for all observers, regardless of their relative motion or of the motion of the source of the light.
The resultant theory has many surprising consequences. Some of these are:
- Relativity of simultaneity: Two events, simultaneous for some observer, may not be simultaneous for another observer if the observers are in relative motion.
- Time dilation: Moving clocks are measured to tick more slowly than an observer's "stationary" clock. To illustrate this further, imagine an observer sitting beside an oval race track, with a motorcycle driver traveling close to the speed of light for several years around the track.The sitting observer will age faster because time for the motorcycle driver will elapse relatively slower.
- Length contraction: Objects are measured to be shortened in the direction that they are moving with respect to the observer.
- Mass-energy equivalence: E = mc2, energy and mass are equivalent and transmutable.
The defining feature of special relativity is the replacement of the Galilean transformations of classical mechanics by the Lorentz transformations. (See Maxwell's equations of electromagnetism and introduction to special relativity).
General relativity
General relativity is a theory of gravitation developed by Einstein in the years 1907–1915. The development of general relativity began with the equivalence principle, under which the states of accelerated motion and being at rest in a gravitational field (for example when standing on the surface of the Earth) are physically identical. The upshot of this is that free fall is inertial motion: In other words an object in free fall is falling because that is how objects move when there is no force being exerted on them, instead of this being due to the force of gravity as is the case in classical mechanics. This is incompatible with classical mechanics and special relativity because in those theories inertially moving objects cannot accelerate with respect to each other, but objects in free fall do so. To resolve this difficulty Einstein first proposed that spacetime is curved. In 1915, he devised the Einstein field equations which relate the curvature of spacetime with the mass, energy, and momentum within it.
Some of the consequences of general relativity are:
- Time goes more slowly in higher gravitational fields. This is called gravitational time dilation.
- Orbits precess in a way unexpected in Newton's theory of gravity. (This has been observed in the orbit of Mercury and in binary pulsars).
- Rays of light bend in the presence of a gravitational field.
- Frame-dragging, in which a rotating mass "drags along" the space time around it.
Technically, general relativity is a metric theory of gravitation whose defining feature is its use of the Einstein field equations. The solutions of the field equations are metric tensors which define the topology of the spacetime and how objects move inertially.
References and links
See the special relativity references and the general relativity references.
For information on the silent film produced on this subject, see The Einstein Theory of Relativity.
References
- ^ lloyd, john; john mitchinson (2006). The General Book of Ignorance. Britain: faber and faber limited. p. 184. ISBN 978-0-571-24139-2. http://en.wikipedia.org/wiki/The_Book_of_General_Ignorance.
External links
 |
Look up theory of relativity in Wiktionary, the free dictionary. |
 |
Wikimedia Commons has media related to: Category:Theory of relativity |
Wikisource has original text related to this article:
|
|||||
|
|||||||||||||||||||||||||||||||||||||
|
||||||||||||||||||||||||||||||||||
This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)
Learn More
 | Einstein, Elsa (Quotes By) |
| relativistic theory (physics) |
| time dilation (Science) |
Help us answer these
Post a question - any question - to the WikiAnswers community:
Copyrights:
 |
 | WordNet. WordNet 1.7.1 Copyright © 2001 by Princeton University. All rights reserved. Read more |
 |
| Wikipedia. This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Theory of relativity". Read more |
Related answers
- How does einstein's theory of relativity help support the big bang theory?
- What does the theory of relativity mean?
ADVERTISEMENT
Answer these
- When are atomic theory and the theory of relativity first proposed?
- When were atomic theory and the theory of relativity first proposed?
Mentioned in
- Einstein, Elsa (Quotes By)
- relativistic theory (physics)
- time dilation (Science)
- curved space-time (relativity)
- fourth dimension (relativity)
- Minkowski electrodynamics (electromagnetism)
- relativistic kinematics (relativity)
- tachyon (particle physics)
- Max Fleischer's Documentary Features (1923 Film)
- Klein-Gordon equation (quantum mechanics)
- relativistic quantum theory (quantum mechanics)
- unified field theory (relativity)
- Eddington, Sir Arthur Stanley (British mathematician)
- relativistic
|
