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Revision as of 00:22, 24 September 2007 view sourceC.Fred (talk | contribs)Autopatrolled, Administrators278,130 edits rv - If this example belongs in this article (of which I'm not convinced), then part of the list item is not where it goes← Previous edit Revision as of 00:59, 24 September 2007 view source Viran (talk | contribs)74 edits I am saying repeatedly to talk on article talk page what is unclear. I can sign up with 100 usernames, create false history and go on reverting what I want on wikipedia. Such tactics will not work. Discuss it with logic on talk page of this article.Next edit →
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Special relativity is a theory of the structure of ]. It was introduced in ]'s ] paper "On the Electrodynamics of Moving Bodies". Special relativity is based on two postulates which are contradictory in ]: Special relativity is a theory of the structure of ]. It was introduced in ]'s ] paper "On the Electrodynamics of Moving Bodies". Special relativity is based on two postulates which are contradictory in ]:
# The laws of physics are the same for all observers in ] relative to one another (]'s ]), # The laws of physics are the same for all observers in ] relative to one another (]'s ]),
# The ] in a ] is the same for all observers, regardless of their relative motion or of the motion of the source of the ]. # The ] in a ] is the same for all observers, regardless of their relative motion or of the motion of the source of the ]. This principle defies common sense. But it can be explained in simple words following way. For stationary observer and moving observer speed of blades of fan is same. For stationary observer and moving observer, speed of particle travelling in coil of spring is same. In two dimension, spring looks like transverse ~wave~. When the '''gravity spring''' between earth and flying away galaxy is stretched, the distance between two coils of ] i.e ] increases resulting in ].


The resultant theory has many surprising consequences. Some of these are: The resultant theory has many surprising consequences. Some of these are:

Revision as of 00:59, 24 September 2007

Two-dimensional analogy of space-time curvature described in General Relativity.

The theory of relativity, or simply relativity, refers specifically to two theories: Albert Einstein's special relativity and general relativity.

The term "relativity" was coined by Max Planck in 1908 to emphasize how special relativity (and later, general relativity) uses the principle of relativity.

Special relativity

Main article: 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". Special relativity is based on two postulates which are contradictory in classical mechanics:

  1. The laws of physics are the same for all observers in uniform motion relative to one another (Galileo's principle of relativity),
  2. 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. This principle defies common sense. But it can be explained in simple words following way. For stationary observer and moving observer speed of blades of fan is same. For stationary observer and moving observer, speed of particle travelling in coil of spring is same. In two dimension, spring looks like transverse ~wave~. When the gravity spring between earth and flying away galaxy is stretched, the distance between two coils of Spring i.e wavelength increases resulting in Red Shift.

The resultant theory has many surprising consequences. Some of these are:

  • Time dilation: Moving clocks tick slower than an observer's "stationary" clock.
  • Length contraction: Objects are observed to be shortened in the direction that they are moving with respect to the observer.
  • Relativity of simultaneity: two events that appear simultaneous to an observer A will not be simultaneous to an observer B if B is moving with respect to A.
  • 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

Main article: 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:

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 intertially.

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.

External links

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