History of special relativity - Revision history

CriticalT: /* Criticisms */

2019-02-14T20:48:07Z

Criticisms

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	===Criticisms===		===Criticisms===
	{{Main\|Criticism of relativity theory}}		{{Main\|Criticism of relativity theory}}
	Some criticized Special Relativity for various reasons, such as lack of empirical evidence, internal inconsistencies, rejection of mathematical physics ''per se'', or philosophical reasons. ~~Although~~ there ~~still~~ are critics of relativity outside the ~~scientific~~ mainstream, ~~the overwhelming majority of~~ scientists ~~agree~~ that ~~Special Relativity has been verified in many different ways and there are no inconsistencies within the theory~~.		Some criticized Special Relativity from the beginning (1905) for various reasons, such as lack of empirical evidence, internal inconsistencies, paradoxes, logic contradictions, rejection of mathematical physics ''per se'', or philosophical reasons. Today, there are a growing number of critics of relativity, but mostly outside the academic theoretical physics mainstream. In addition, most scientists doing real world work that includes "relativistic" effects come to reject relativity to get their physical mechanisms to work (e.g,. GPS).

	==See also==		==See also==

NickPercival: /* Time dilation and twin paradox */ correcting relativists view of Twin ParaDOX

2017-07-14T17:51:16Z

Time dilation and twin paradox: correcting relativists view of Twin ParaDOX

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	Einstein (1907a) proposed a method for detecting the [[transverse Doppler effect]] as a direct consequence of time dilation. And in fact, that effect was measured in 1938 by [[Herbert E. Ives]] and G. R. Stilwell ([[Ives–Stilwell experiment]]).<ref>Miller (1981), 245–253</ref> And Lewis and Tolman (1909) described the reciprocity of [[time dilation]] by using two light clocks A and B, traveling with a certain relative velocity to each other. The clocks consist of two plane mirrors parallel to one another and to the line of motion. Between the mirrors a light signal is bouncing, and for the observer resting in the same reference frame as A, the period of clock A is the distance between the mirrors divided by the speed of light. But if the observer looks at clock B, he sees that within that clock the signal traces out a longer, angled path, thus clock B is slower than A. However, for the observer moving alongside with B the situation is completely in reverse: Clock B is faster and A is slower. Also Lorentz (1910–1912) discussed the reciprocity of time dilation and analyzed a clock "paradox", which apparently occurs as a consequence of the reciprocity of time dilation. Lorentz showed that there is no paradox if one considers that in one system only one clock is used, while in the other system two clocks are necessary, and the relativity of simultaneity is fully taken into account.		Einstein (1907a) proposed a method for detecting the [[transverse Doppler effect]] as a direct consequence of time dilation. And in fact, that effect was measured in 1938 by [[Herbert E. Ives]] and G. R. Stilwell ([[Ives–Stilwell experiment]]).<ref>Miller (1981), 245–253</ref> And Lewis and Tolman (1909) described the reciprocity of [[time dilation]] by using two light clocks A and B, traveling with a certain relative velocity to each other. The clocks consist of two plane mirrors parallel to one another and to the line of motion. Between the mirrors a light signal is bouncing, and for the observer resting in the same reference frame as A, the period of clock A is the distance between the mirrors divided by the speed of light. But if the observer looks at clock B, he sees that within that clock the signal traces out a longer, angled path, thus clock B is slower than A. However, for the observer moving alongside with B the situation is completely in reverse: Clock B is faster and A is slower. Also Lorentz (1910–1912) discussed the reciprocity of time dilation and analyzed a clock "paradox", which apparently occurs as a consequence of the reciprocity of time dilation. Lorentz showed that there is no paradox if one considers that in one system only one clock is used, while in the other system two clocks are necessary, and the relativity of simultaneity is fully taken into account.

	[[File:Max von Laue.jpg\|thumb\|left\|Max von Laue]] A similar situation was created by [[Paul Langevin]] in 1911 with what was later called the "[[twin paradox]]", where he replaced the clocks by persons (Langevin never used the word "twins" but his description contained all other features of the paradox). Langevin ~~solved~~ the paradox by alluding to the fact that one twin accelerates and changes direction, so ~~Langevin could show that~~ the symmetry is broken and the accelerated twin is younger. However, Langevin himself interpreted ~~this~~ as a hint as to the existence of an aether~~. Although Langevin's explanation is still accepted by some, his conclusions regarding the aether were not generally accepted~~. Laue (1913) pointed out that any acceleration can be made arbitrarily small in relation to the inertial motion of the twin, and that the real explanation is that one twin is at rest in two different inertial frames during his journey, while the other twin is at rest in a single inertial frame. Laue was ~~also~~ the first to analyze the situation based on Minkowski's spacetime model for special relativity – showing how the world lines of inertially moving bodies maximize the proper time elapsed between two events.<ref>Miller (1981), 257–264</ref>		[[File:Max von Laue.jpg\|thumb\|left\|Max von Laue]] A similar situation was created by [[Paul Langevin]] in 1911 with what was later called the "[[twin paradox]]", where he replaced the clocks by persons (Langevin never used the word "twins" but his description contained all other features of the paradox). Langevin tried to solve the paradox by alluding to the fact that one twin accelerates and changes direction, so the symmetry is broken and the accelerated twin is younger. However, this attempt has been shown to fail (see [[Twin paradox]] section 3) for multiple obvious reasons. Further, Langevin himself interpreted even his failed solution as a hint as to the existence of an aether. Laue (1913) pointed out that any acceleration can be made arbitrarily small in relation to the inertial motion of the twin, and that the real explanation is that one twin is at rest in two different inertial frames during his journey, while the other twin is at rest in a single inertial frame. However, this explanation was also seen as being obviously flawed and further, if true, would render special relativity worthless as it means that special relativity cannot be applied by any observer or to any instrument that has or will experience acceleration. Laue was the first to analyze the situation based on Minkowski's spacetime model for special relativity – showing how the world lines of inertially moving bodies maximize the proper time elapsed between two events.<ref>Miller (1981), 257–264</ref>. However, when looked at from the frame of the traveling twin in the outbound leg plus the frame of traveling twin in the inbound leg a contradictory conclusion results.[[User:NickPercival\|NickPercival]] ([[User talk:NickPercival\|talk]]) 10:50, 14 July 2017 (PDT)

	====Acceleration====		====Acceleration====

NickPercival: /* Electrodynamics of moving bodies */ More objective view of SR

2017-07-13T22:41:18Z

Electrodynamics of moving bodies: More objective view of SR

NickPercival: 1 revision imported

2017-07-05T18:09:45Z

1 revision imported

Show changes

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	====Electrodynamics of moving bodies====		====Electrodynamics of moving bodies====
	[[File:Einstein1921 by F Schmutzer 4.jpg\|thumb\|right\|Albert Einstein, 1921]]		[[File:Einstein1921 by F Schmutzer 4.jpg\|thumb\|right\|Albert Einstein, 1921]]
	On September 26, 1905 (received June 30), Albert Einstein published his ~~[[Annus Mirabilis Papers\|annus mirabilis]]~~ paper on what is now called ''special relativity''. Einstein's paper includes a fundamental new definition of space and time (all time and space coordinates in all reference frames are on an equal footing, so there is no physical basis for distinguishing "true" from "apparent" time) and makes the aether an unnecessary concept, at least in regard to inertial motion. Einstein ~~identified~~ two fundamental principles, the [[principle of relativity]] and the ''principle of the constancy of light'' (''light principle''), which ostensibly served as the axiomatic basis of his theory. To better understand Einstein's step, a summary of the situation before 1905, as it was described above, shall be given<ref>Whittaker (1951)</ref> (it must be remarked that Einstein was familiar with the 1895 theory of Lorentz, and ''[[Science and Hypothesis]]'' by Poincaré, but not their papers of 1904-1905):		On September 26, 1905 (received June 30), Albert Einstein published his paper on what is now called ''special relativity''. Einstein's paper includes his fundamental new definition of space and time in which all time and space coordinates in all reference frames are alleged to be on an equal footing, so there is no physical basis for distinguishing "true" from "apparent" time and would, therefore, makes the aether an unnecessary concept, at least in regard to inertial motion. Einstein assumed two fundamental principles, the [[principle of relativity]] and the ''principle of the constancy of light'' (''light principle''), which ostensibly served as the axiomatic basis of his theory. To better understand Einstein's step, a summary of the situation before 1905, as it was described above, shall be given<ref>Whittaker (1951)</ref> (it must be remarked that Einstein was familiar with the 1895 theory of Lorentz, and ''[[Science and Hypothesis]]'' by Poincaré, but not their papers of 1904-1905):

	:''a'') Maxwell's electrodynamics, as presented by Lorentz in 1895, was the most successful theory at this time. Here, the speed of light is constant in all directions in the stationary aether and completely independent of the velocity of the source;		:''a'') Maxwell's electrodynamics, as presented by Lorentz in 1895, was the most successful theory at this time. Here, the speed of light is constant in all directions in the stationary aether and completely independent of the velocity of the source;
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	with the following consequences for the speed of light and the theories known at that time:		with the following consequences for the speed of light and the theories known at that time:

	#The speed of light is not composed of the speed of light in vacuum and the velocity of a preferred frame of reference, by ''b''~~. This contradicts the theory of the (nearly) stationary aether~~.		#The speed of light is not composed of the speed of light in vacuum and the velocity of a preferred frame of reference, by ''b''.
	#The speed of light is not composed of the speed of light in vacuum and the velocity of the light source, by ''a'' and ''c''. This contradicts the [[emission theory]].		#The speed of light is not composed of the speed of light in vacuum and the velocity of the light source, by ''a'' and ''c''. This contradicts the [[emission theory]].
	#The speed of light is not composed of the speed of light in vacuum and the velocity of an aether that would be dragged within or in the vicinity of matter, by ''a, c'', and ''d''. This contradicts the hypothesis of the [[aether drag hypothesis\|complete aether drag]].		#The speed of light is not composed of the speed of light in vacuum and the velocity of an aether that would be dragged within or in the vicinity of matter, by ''a, c'', and ''d''. This contradicts the hypothesis of the [[aether drag hypothesis\|complete aether drag]].
	#The speed of light in moving media is not composed of the speed of light when the medium is at rest and the velocity of the medium, but is determined by Fresnel's dragging coefficient, by ''c''.<ref group=W>For many other experiments on light constancy and relativity, see PhysicsFaq: [http://math.ucr.edu/home/baez/physics/Relativity/SR/experiments.html What is the experimental basis of special relativity?]</ref>		#The speed of light in moving media is not composed of the speed of light when the medium is at rest and the velocity of the medium, but is determined by Fresnel's dragging coefficient, by ''c''.<ref group=W>For many other experiments on light constancy and relativity, see PhysicsFaq: [http://math.ucr.edu/home/baez/physics/Relativity/SR/experiments.html What is the experimental basis of special relativity?]</ref>

	In order to make the principle of relativity as required by Poincaré an exact law of nature in the immobile aether theory of Lorentz, the introduction of a variety [[Ad hoc hypothesis\|ad hoc hypotheses]] was required, such as the contraction hypothesis, local time, the Poincaré stresses, etc.. This method was criticized by many scholars, since the assumption of ~~a conspiracy of~~ effects which completely prevent the discovery of the aether drift is ~~considered~~ to be very improbable, and it would violate [[Occam's razor]] ~~as well~~.<ref name="Miller 1982"/><ref name=holt>Holton (1988)</ref><ref name="Pais 1982">Pais (1982)</ref><ref name="Jannssen 1995">Jannssen (1995)</ref> Einstein is considered the first who completely dispensed with ~~such~~ auxiliary hypotheses and drew the direct conclusions from the ~~facts~~ stated above:<ref name="Miller 1982"/><ref name=holt>Holton (1988)</ref><ref name="Pais 1982"/><ref name="Jannssen 1995"/> that the relativity principle is correct and the directly observed speed of light is the same in all inertial reference frames. Based on ~~his axiomatic approach~~, Einstein was able to derive ''all results'' obtained by his predecessors – and in addition the formulas for the [[relativistic Doppler effect]] and [[relativistic aberration]] – in a few pages, while prior to 1905 his competitors had devoted years of long, complicated work to arrive at the ~~same mathematical formalism~~. Before 1905 Lorentz and Poincaré had adopted these same principles, as necessary to achieve their final results, but didn't recognize that they were also sufficient ~~in the sense that there was no immediate logical need to assume the existence of a stationary aether~~ in order to arrive at the Lorentz transformations.<ref name="Darrigol 2005, 15-18"/><ref name=Jannn>Janssen (1995), Ch. 4</ref> ~~Another~~ reason for Einstein's early rejection of the aether in any form (which he later partially retracted) may have been related to his work on [[quantum physics]]. Einstein discovered that light can also be described (at least heuristically) as a kind of particle, so the aether as the medium for electromagnetic "waves" (which was highly important for Lorentz and Poincaré) no longer fitted into his conceptual scheme.<ref>Rynasiewicz/Renn (2006)</ref>		In order to make the principle of relativity as required by Poincaré an exact law of nature in the immobile aether theory of Lorentz, the introduction of a variety of allegedly [[Ad hoc hypothesis\|ad hoc hypotheses]] was required, such as the contraction hypothesis, local time, the Poincaré stresses, etc.. This method was criticized by many scholars, since the assumption of those effects which completely prevent the discovery of the aether drift is alleged to be very improbable, and it would violate [[Occam's razor]].<ref name="Miller 1982"/><ref name=holt>Holton (1988)</ref><ref name="Pais 1982">Pais (1982)</ref><ref name="Jannssen 1995">Jannssen (1995)</ref> On the other hand, those effects were conceived in response to the empirical data shown abve.

			Einstein is considered the first who completely dispensed with those auxiliary hypotheses and drew the direct conclusions from the conclusions stated above:<ref name="Miller 1982"/><ref name=holt>Holton (1988)</ref><ref name="Pais 1982"/><ref name="Jannssen 1995"/> that the relativity principle is correct and the directly observed speed of light is the same in all inertial reference frames. Based on these assumptions, Einstein was able to derive ''all results'' obtained by his predecessors – and in addition the formulas for the [[relativistic Doppler effect]] and [[relativistic aberration]] – in a few pages, while prior to 1905 his competitors had devoted years of long, complicated work to arrive at the base of knowledge used by Einstein. Before 1905 Lorentz and Poincaré had adopted these same principles, as necessary to achieve their final results, but didn't recognize that they were also sufficient in order to arrive at the original Lorentz transformations with their Lorentzian physical interpretation.<ref name="Darrigol 2005, 15-18"/><ref name=Jannn>Janssen (1995), Ch. 4</ref> One reason for Einstein's early rejection of the aether in any form (which he later partially retracted) may have been related to his work on [[quantum physics]]. Einstein discovered that light can also be described (at least heuristically) as a kind of particle, so the aether as the medium for electromagnetic "waves" (which was highly important for Lorentz and Poincaré) no longer fitted into his conceptual scheme.<ref>Rynasiewicz/Renn (2006)</ref>

	It's notable that Einstein's paper contains no direct references to other papers. However, many historians of science like Holton,<ref name=holt /> Miller,<ref name="Miller 1981"/> Stachel,<ref name=stach>Stachel (1982)</ref> have tried to find out possible influences on Einstein. He stated that his thinking was influenced by the [[Empiricism\|empiricist]] philosophers [[David Hume]] and [[Ernst Mach]]. Regarding the Relativity Principle, the [[moving magnet and conductor problem]] (possibly after reading a book of [[August Föppl]]) and the various negative aether drift experiments were important for him to accept that principle — but he denied any significant influence of the ''most important'' experiment: the Michelson–Morley experiment.<ref name=stach /> Other likely influences include Poincaré's ''[[Science and Hypothesis]]'', where Poincaré presented the Principle of Relativity (which, as has been reported by Einstein's friend Maurice Solovine, was closely studied and discussed by Einstein and his friends over a period of years before the publication of Einstein's 1905 paper),<ref>Darrigol (2004), 624</ref> and the writings of [[Max Abraham]], from whom he borrowed the terms "Maxwell-Hertz equations" and "longitudinal and transverse mass".<ref>Miller (1981), 86–92</ref>		It's notable that Einstein's paper contains no direct references to other papers. However, many historians of science like Holton,<ref name=holt /> Miller,<ref name="Miller 1981"/> Stachel,<ref name=stach>Stachel (1982)</ref> have tried to find out possible influences on Einstein. He stated that his thinking was influenced by the [[Empiricism\|empiricist]] philosophers [[David Hume]] and [[Ernst Mach]]. Regarding the Relativity Principle, the [[moving magnet and conductor problem]] (possibly after reading a book of [[August Föppl]]) and the various negative aether drift experiments were important for him to accept that principle — but he denied any significant influence of the ''most important'' experiment: the Michelson–Morley experiment.<ref name=stach /> Other likely influences include Poincaré's ''[[Science and Hypothesis]]'', where Poincaré presented the Principle of Relativity (which, as has been reported by Einstein's friend Maurice Solovine, was closely studied and discussed by Einstein and his friends over a period of years before the publication of Einstein's 1905 paper),<ref>Darrigol (2004), 624</ref> and the writings of [[Max Abraham]], from whom he borrowed the terms "Maxwell-Hertz equations" and "longitudinal and transverse mass".<ref>Miller (1981), 86–92</ref>