# Encyclopedia

### From Wikipedia, the free encyclopedia

Two-dimensional projection of a three-dimensional analogy of space-time curvature described in General Relativity.
.The theory of relativity, or simply relativity, encompasses two theories of Albert Einstein: special relativity and general relativity.^ Contradiction between the special and general theories of relativity ...
• Crank Dot Net | relativity 11 January 2010 8:32 UTC www.crank.net [Source type: FILTERED WITH BAYES]

^ The two great breakthroughs were the Special Theory of Relativity (1905) and the General Theory of Relativity (1915).
• Relativity Theory 11 January 2010 8:32 UTC www.marxist.com [Source type: Original source]

^ At present, the special theory of relativity exists in physics as generally accepted theory.
• Elimination of internal contradictions of special theory of relativity. 11 January 2010 8:32 UTC www.poshelaev.nm.ru [Source type: Original source]

.However, the word "relativity" is sometimes used in reference to Galilean invariance.^ However, due to time dilation, the muons break apart much more slowly relative to the reference frame of Earth.
• NASA - Relativity 11 January 2010 8:32 UTC www.nasa.gov [Source type: FILTERED WITH BAYES]

^ As all this relativity stuff percolated relentlessly between my ears early last year, I was struggling with how we can use dynamic reference points as traders.
• Relativity 11 January 2010 8:32 UTC www.zealllc.com [Source type: FILTERED WITH BAYES]

^ If astronomers can use the cosmic background radiation as a reference frame doesn't that invalidate special relativity?
• Gravity Probe B - Special & General Relativity Questions and Answers 11 January 2010 8:32 UTC einstein.stanford.edu [Source type: FILTERED WITH BAYES]

.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.^ Contradiction between the special and general theories of relativity ...
• Crank Dot Net | relativity 11 January 2010 8:32 UTC www.crank.net [Source type: FILTERED WITH BAYES]

^ This led to the theory of special relativity .
• Relativity Tutorial 11 January 2010 8:32 UTC www.astro.ucla.edu [Source type: FILTERED WITH BAYES]

^ In this sense we speak of the special principle of relativity, or special theory of relativity.
• — Relativity: The Special and the General Theory — Albert Einstein — XHTML eReader — Library.SeaPlusPlus.net/physics — Richard R Plourde 11 January 2010 8:32 UTC library.seaplusplus.net [Source type: FILTERED WITH BAYES]

## Special relativity

USSR stamp dedicated to Albert Einstein
.Special relativity is a theory of the structure of spacetime.^ The answer to this question is the special theory of relativity.

^ It is omission of the special theory of relativity.
• Elimination of internal contradictions of special theory of relativity. 11 January 2010 8:32 UTC www.poshelaev.nm.ru [Source type: Original source]

^ This is particularly true of special relativity theory.
• Einstein's Special Theory of Relativity - An Easy (I hope!) Explanation 11 January 2010 8:32 UTC www.squidoo.com [Source type: General]

.It was introduced in Albert Einstein's 1905 paper "On the Electrodynamics of Moving Bodies" (for the contributions of many other physicists see History of special relativity).^ These included On the Electrodynamics of Moving Bodies (1905) containing what became known as the special theory of relativity .
• Einstein's Implicit Theory of Relativity -- of Cognitive Property? Unexamined influence of patent office procedures 11 January 2010 8:32 UTC www.laetusinpraesens.org [Source type: Reference]

^ Einstein's analysis of simultaneity is provided in the first section of the 1905 special relativity paper.
• Discovering the Relativity of Simultaneity 11 January 2010 8:32 UTC www.pitt.edu [Source type: FILTERED WITH BAYES]

^ BackLinks The special theory of relativity was proposed in 1905 by Albert Einstein .
• The special theory of relativity was proposed in 1905 by Albert Einstein - From the New Universe 11 January 2010 8:32 UTC www.newuniverse.co.uk [Source type: FILTERED WITH BAYES]

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 (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.
.The resultant theory agrees with experiment better than classical mechanics, e.g.^ As well, if I could make you bigger than the universe and put you outside, you could apply the Quantum Mechanics theory to our universe of planets and stars.
• Theory of Universal Relativity - Shrinking Theory 11 January 2010 8:32 UTC www.crownedanarchist.com [Source type: Original source]

^ Concerning the experiment of Michelson and Morley , H. A. Lorentz showed that the result obtained at least does not contradict the theory of an aether at rest.

^ In each of these tests, general relativity yields predictions that agree quantitatively, and in some cases qualitatively, better with experimental results than Newtonian theory.
• Council for Christian Colleges & Universities - Integrative Topics in Modern Physics 11 January 2010 8:32 UTC www.cccu.org [Source type: FILTERED WITH BAYES]

in the .Michelson-Morley experiment that supports postulate 2, but also has many surprising consequences.^ Michelson and Morley did this experiment in the 1880's.

^ Michelson-Morley experiment .
• special relativity@Everything2.com 11 January 2010 8:32 UTC everything2.com [Source type: FILTERED WITH BAYES]

^ Concerning the experiment of Michelson and Morley , H. A. Lorentz showed that the result obtained at least does not contradict the theory of an aether at rest.

Some of these are:
• Relativity of simultaneity: Two events, simultaneous for one 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.
• 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.^ According to the special theory of relativity, the equations which express the general laws of nature pass over into equations of the same form when, by making use of the Lorentz transformation, we replace the space-time variables x , y , z , t , of a (Galilean) reference-body K by the space-time variables x′ , y′ , z′ , t′ , of a new reference-body K′ .
• — Relativity: The Special and the General Theory — Albert Einstein — XHTML eReader — Library.SeaPlusPlus.net/physics — Richard R Plourde 11 January 2010 8:32 UTC library.seaplusplus.net [Source type: FILTERED WITH BAYES]

^ This led the Dutch professor, Lorentz, and myself to develop the theory of special relativity.
• — The Einstein Theory of Relativity — H. A. Lorentz — XHTML eReader — Library.SeaPlusPlus.net/physics — Richard R Plourde 11 January 2010 8:32 UTC library.seaplusplus.net [Source type: Original source]

^ Special relativity allows us to define a distance from the origin for all the points on a world-line, allowing the world-line to be a set of points that have physically distinguishable properties.
• Spacetime - Einstein's Relativity, Space, Time, Quantum Gravity, Quantum Physics, and the Existence of Time 11 January 2010 8:32 UTC www.ws5.com [Source type: FILTERED WITH BAYES]

.^ Maxwell's equations were already compatible with Special Relativity, however Newton's equations were not.

^ The special theory of relativity has rendered the Maxwell-Lorentz theory so plausible, that the latter would have been generally accepted by physicists even if experiment had decided less unequivocally in its favor.
• — Relativity: The Special and the General Theory — Albert Einstein — XHTML eReader — Library.SeaPlusPlus.net/physics — Richard R Plourde 11 January 2010 8:32 UTC library.seaplusplus.net [Source type: FILTERED WITH BAYES]

^ Main article: Formulation of Maxwell's equations in special relativity Maxwell's equations in the 3D form are already consistent with the physical content of special relativity.
• The special theory of relativity was proposed in 1905 by Albert Einstein - From the New Universe 11 January 2010 8:32 UTC www.newuniverse.co.uk [Source type: FILTERED WITH BAYES]

## 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.^ Votes:0 General Theory of Relativity In 1915 Einstein developed the theory of general relativity in which he considered objects accelerated with respect to one another.
• Relativity - Education Resource - StudySphere 11 January 2010 8:32 UTC www.studysphere.com [Source type: Academic]

^ A physical theory of relativity .
• Many-Minds Relativity - a knol by Claes Johnson 11 January 2010 8:32 UTC knol.google.com [Source type: FILTERED WITH BAYES]

^ This prediction was based on his general theory of relativity, which was published in 1915, ten years after he published his special theory of relativity.
• Classical Physics, Quantum Mechanics, Relativity, Super String Theory And Mediation 11 January 2010 8:32 UTC mediate.com [Source type: FILTERED WITH BAYES]

.The upshot of this is that free fall is inertial motion; 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.^ How can there be no distance?
• Theory of Universal Relativity - Shrinking Theory 11 January 2010 8:32 UTC www.crownedanarchist.com [Source type: Original source]

^ How can the dominoes fall if there is no time for the dominoes to fall?
• Spacetime - Einstein's Relativity, Space, Time, Quantum Gravity, Quantum Physics, and the Existence of Time 11 January 2010 8:32 UTC www.ws5.com [Source type: FILTERED WITH BAYES]

^ There is no mysterious force called gravity.

.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.^ The answer to this question is the special theory of relativity.

^ Because accelerations are also relative.
• Theory Of Relativity - Page 7 - GateWorld Forum 11 January 2010 8:32 UTC forum.gateworld.net [Source type: FILTERED WITH BAYES]

^ One example is the Special Theory of Relativity.
• A Dissident View of Relativity Theory by William H. Cantrell, Ph.D. 11 January 2010 8:32 UTC www.infinite-energy.com [Source type: FILTERED WITH BAYES]

.To resolve this difficulty Einstein first proposed that spacetime is curved.^ Curved spacetime, Einstein's field equations.
• Council for Christian Colleges & Universities - Integrative Topics in Modern Physics 11 January 2010 8:32 UTC www.cccu.org [Source type: FILTERED WITH BAYES]

^ The difficulty, as Einstein stressed, was not in writing down the solution of this mathematical problem, but in conceiving of the problem in the first place, and then showing that it represents a viable law of gravitation.
• Who Invented Relativity? 11 January 2010 8:32 UTC www.mathpages.com [Source type: FILTERED WITH BAYES]

^ Since both of these frames describe the same spacetime, Einstein proposed that the interval between two events should be the same for all inertial observers.

.In 1915, he devised the Einstein field equations which relate the curvature of spacetime with the mass, energy, and momentum within it.^ "Derivation/discussion of the Einstein mass-energy equation from conservation of energy and conservation of momentum ...
• Crank Dot Net | relativity 11 January 2010 8:32 UTC www.crank.net [Source type: FILTERED WITH BAYES]

^ Equating energy to mass to space .
• The Contradiction of Theory of Relativity with Quantum Mechanics | Science Blog 11 January 2010 8:32 UTC www.scienceblog.com [Source type: FILTERED WITH BAYES]

^ The rest energy is related to the mass according to the celebrated equation discussed above: .
• The special theory of relativity was proposed in 1905 by Albert Einstein - From the New Universe 11 January 2010 8:32 UTC www.newuniverse.co.uk [Source type: FILTERED WITH BAYES]

Some of the consequences of general relativity are:
.
• Time goes more slowly in higher gravitational fields.^ The speed of transition will, of course, be gradual as one gravitational field yields to another more dominant field in its local neighborhood.
• A Dissident View of Relativity Theory by William H. Cantrell, Ph.D. 11 January 2010 8:32 UTC www.infinite-energy.com [Source type: FILTERED WITH BAYES]

^ In essence, this formulation is not anything more than a theory of gravitation that is somehow artificially relieved from the unitary field of unknown structure.
• UNITARY FOUNDATIONS OF PHYSICS - CRITICISM OF THE THEORY OF RELATIVITY 11 January 2010 8:32 UTC asisbg.netfirms.com [Source type: Academic]

^ Do you age more slowly when traveling at higher velocities?
• Astronomy Cast - Ep. 9: Einstein's Theory of Special Relativity 11 January 2010 8:32 UTC www.astronomycast.com [Source type: General]

.This is called gravitational time dilation.
• Orbits precess in a way unexpected in Newton's theory of gravity.^ This phenomenon is called Time dilation.
• The special theory of relativity was proposed in 1905 by Albert Einstein - From the New Universe 11 January 2010 8:32 UTC www.newuniverse.co.uk [Source type: FILTERED WITH BAYES]

^ The essence of this "paradox," and many others that appear in relativity theory, is that the measuring process takes time, and that both space and time become distorted in different ways in different frames.
• Theory of Universal Relativity - Shrinking Theory 11 January 2010 8:32 UTC www.crownedanarchist.com [Source type: Original source]

^ When you start bringing in energy, one thing that Newton's theory of gravity doesn't take into account is that energy has mass.
• Astronomy Cast - Ep. 44: Einstein's Theory of General Relativity 11 January 2010 8:32 UTC www.astronomycast.com [Source type: FILTERED WITH BAYES]

(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.
• The Universe is expanding, and the far parts of it are moving away from us faster than the speed of light.
.Technically, general relativity is a metric theory of gravitation whose defining feature is its use of the Einstein field equations.^ Episode 44: Einstein's Theory of General Relativity (15.3MB) General Relativity .
• Astronomy Cast - Ep. 44: Einstein's Theory of General Relativity 11 January 2010 8:32 UTC www.astronomycast.com [Source type: FILTERED WITH BAYES]

^ Theory of Relativity Hoax - Einstein the impostor .
• Theory of Relativity Hoax - Einstein the impostor 11 January 2010 8:32 UTC theflatearthsociety.net [Source type: FILTERED WITH BAYES]

^ Einstein’s special theory of relativity, clocks in a gravitational field run SLOW. .
• Proving the theory of relativity in your minivan | GeekDad | Wired.com 11 January 2010 8:32 UTC www.wired.com [Source type: Academic]

.The solutions of the field equations are metric tensors which define the topology of the spacetime and how objects move inertially.^ How do we operationally define an inertial frame?

^ Curved spacetime, Einstein's field equations.
• Council for Christian Colleges & Universities - Integrative Topics in Modern Physics 11 January 2010 8:32 UTC www.cccu.org [Source type: FILTERED WITH BAYES]

^ How can a moving object increase its mass?
• Relativity Theory 11 January 2010 8:32 UTC www.marxist.com [Source type: Original source]

## Further reading

• Bergmann, Peter G. (1976). .Introduction to the Theory of Relativity.^ The Meaning of Einstein's Equation A relatively simple introduction to the fundamental geometric nature of the theory of general relativity (intermediate) .
• Spacetime - Einstein's Relativity, Space, Time, Quantum Gravity, Quantum Physics, and the Existence of Time 11 January 2010 8:32 UTC www.ws5.com [Source type: FILTERED WITH BAYES]

^ Introduction to the Theory of Relativity Part I: History .
• Introduction to the Theory of Relativity Part I: History || kuro5hin.org 11 January 2010 8:32 UTC www.kuro5hin.org [Source type: FILTERED WITH BAYES]

^ Gregory L. Naber , The Geometry of Minkowski Spacetime: An Introduction to the Mathematics of the Special Theory of Relativity .
• A Guide to Relativity Books 11 January 2010 8:32 UTC math.ucr.edu [Source type: General]

Dover Publications. ISBN 0-486-63282-2.

# Simple English

File:Albert Einstein 1979 USSR
$E=mc^2$

The Theory of relativity was developed by Albert Einstein in the early 1900s. There are two theories of relativity. The first is Special Relativity and the second is General Relativity. Both are based on the Principle of relativity, which was created by Galileo Galilei in the 1600s.

## Special relativity

Special Relativity says that every person has their own time. One person's clock says something different from another person's clock. The reason a person's time can be different from another's is because of Time Dilation, which can be thought of more easily by the Twin Paradox.

### Twin paradox

The Twin Paradox shows how time changes because of speed and mass. The faster someone or something moves or the more mass they have, then the slower time passes for them. This is shown by a pair of twins. Imagine that the first twin moves at a fast speed, near the speed of light for example, while the other twin stays in one general location. When the first twin returns from his trip, he will be younger than the second twin. Thus time and speed are related.

• Speed and mass affect how fast time moves

## General relativity

General Relativity adds gravity to Special Relativity. It says that space and time are joined together. Space is like a grid. Balls (planets) on the grid bend it because of their mass or speed. As one ball moves towards another it falls towards the other ball due to the dent in the grid. It can be shown by putting heavy balls on a trampoline. The dent in the grid is like gravity shown by the planets.

### How it works with special relativity

If space and time are one thing represented by a grid and heavy objects stretch out the grid, that means that time passes more slowly near heavy objects. This has been shown in experiments by comparing very accurate clocks on Earth (where Earth's gravity is strong) with very accurate clocks on satellites or rockets in space (where Earth's gravity is weak).

## Criticism of relativity

G. O. Mueller wrote a whole encyclopedia arguing against Einstein's relativity. Mueller, and many other philosophers say that space and time are categories of perception, not distortable "things," and so ideas of relativity that treat them as "things" can not be correct. Paul Dirac and others have said that constants may change over time, including the speed of light. Mueller lists about 4000 Einstein-critical works since 1905, suggesting rethinking relativity.

## References

• Hawking, Stephen. The Universe in a Nutshell. Bantam Books, 2001.

## Other websites

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