Einstein did not derive E =mc2 first

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The mass-energy equation E=mc^2 existed prior to Einstein's derivation in 1905, with contributions from physicists like Newton, Preston, Poincaré, De Pretto, and Hasenöhrl. Einstein's work built upon these earlier theories, yet he did not acknowledge them in his publications. Max Planck later derived the equation independently and noted limitations in Einstein's approach. The discussion highlights the lack of recognition for previous contributors and raises questions about the originality of Einstein's derivation. Overall, the origins of E=mc^2 are more complex than commonly understood, involving multiple scientists' insights leading up to Einstein's formulation.
  • #31
A photon that reaches us from a distant galaxy has not been scattered by any matter in between. That photon has traveled at c the whole way, along a null geodesic. In fact that can be said of all the photons that comprise the images of what we can see. Matter in the universe, matter degrading the cosmic vacuum, is only a perturbation, and you can't get any effective denial of SR out of it.
 
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  • #32
Nommos Prime (Dogon) said:
The KEY is that C is only constant in a VACUUM.
One (minor) nitpick with that: "c" is by definition the speed of light in a vacuum. The speed of light in other media is not properly denoted by "c".

Also, referring to "c" as "the speed of light" is misleading. While the description is common, and accurate in a vacuum, it tends to make people think that light is key part. The thing about c that is important here is not its relationship with light, but rather its relationship with spacetime. I view c itself as the more elementary thing, and the fact that light travels at it an artifact of the nature of light (there was nothing else to limit it, so it travels as fast as possible: c).

All of that is to the side of my point though: Relativity requires that c is the same for all observers at any spacetime event - and this is very well supported experimentally. Relativity does not require that c is the same at all spacetime events - and this idea is only weakly supported by observations. The many experiments confirming relativity do not touch on it at all.

This has nothing to do with speed of light through media - it is about the fundamental conversion factor between space and time.
 
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  • #33
OneEye said:
I'm not starting a fight here, nor am I trying to bolster or assault anyone, but here are a few thoughts:

1) c is variable under general relativity.

2) All measurements of c have been made under relatively low-speed and limited local conditions.

3) c is, of course, not constant in any medium other than a vaccuum.

4) I'm quite murky on this, but I am also quite sure that some recent measurements of distant stars have shown that either c or alpha has probably been different in the past.

I am not poking at SR here. I am just pointing out some cases in which the statement The speed of light IS NOT a constant (and NEVER has been). can be said to be true.

Though this may not be what "Nommos Prime (Dogon)" means...

Anyway... I'm butting out now.


isn't a vacuum the only medium "through" which light travels, really?


(y'know, it might get absorbed by matter, then released again, but when it's actually light by itself, it exists only in the vacuum)
(could be totally wrong, been smoking way too much crack!)
 
  • #34
OneEye said:
1) c is variable under general relativity.

And I thought that in general relativity, ds2 = 0 for light.
 
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  • #35
OneEye said:
1) c is variable under general relativity.
This, or variations, has been mentioned several times here in PF. Is it a reference to http://relativity.livingreviews.org/Articles/lrr-2001-4/node10.html#SECTION00034000000000000000 (discussed in section 3.4.2 "The time delay of light")?

It's also covered in another "Living Review", http://relativity.livingreviews.org/Articles/lrr-2003-1/article_prep.html , under "Signal propogation delay".

Somewhat OT, the debate about whether tests can be done of the constancy of c, given how units of time and distance/length are now defined, is a very interesting one, especially when we examine the idea that the "old" definitions are "theory-free". Another thread perhaps. :smile:
 
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  • #36
shrumeo said:
isn't a vacuum the only medium "through" which light travels, really?
Yes. The phrase "light traveling through a medium" is misleading.
 
  • #37
ajay22444 said:
Origin and escalation of mass-energy equation E=mc^2

Ajay Sharma
Community Science Centre. DOE. Post Box 107 Shimla 171001 HP INDIA
Email physicsajay@lycos.co.uk , physicsajay@yahoo.com

Einstein’s 27 Sep 1905 paper available at http://www.fourmilab.ch/etexts/einstein/E_mc2/www/




Abstract

E=mc^2existed before Einstein’s derivation in Sep. 1905. Isaac Newton, S. Tolver Preston, Poincaré , De Pretto and F. Hasenöhrl are the philosophers and physicists who have given idea of E=mc^2. Einstein derived existing E=mc^2starting with result of relativistic variation of light energy, but finally obtained L =mc^2 under applying classical conditions (v<<c). After Einstein, Max Plank also derived the same independently. Max Born has expressed surprise over non-inclusion of previous references by Einstein in the derivation of E=mc^2.




1.0 Contributors of equation E =mc2

Before Einstein, among other physicists, Isaac Newton [1], English S. T. Preston [2] in 1875, French Poincaré [3,4] in 1900, Italian De Pretto [5] in 1903, German F. Hasenöhrl [6,7] made significant contributions in speculations and derivations of E=mc^2. After Einstein Planck [8] has also derived E=mc^2 independently. J J Thomson in 1888 is also believed to have anticipated E=mc^2from Maxwell’s equations.
(i) Issac Newton (1642-1727)
The Great Sir Isaac Newton [1] has quoted "Gross bodies and light are convertible into one another...", 1704). In 1704 Newton wrote the book “Optiks”. Newton also put forth Corpuscular Theory of Light
(ii) S. Tolver Preston
S. Tolver Preston [2], who made predictions which are based essentially upon E=mc^2. Preston in his book Physics of the Ether proposed in 1875 that vast amount of energy can be produced from matter. Preston determined that one grain could lift a 100,000-ton object up to a height of 1.9 miles. This deduction yields the essence of equation E=mc^2.
(iii) Jules Henri Poincaré (1854-1912)
Poincaré in 1900 [3,4] put forth an expression for what he called the "momentum of radiation" M_R. It is M_R = S/c^2, where S represents the flux of radiation and c is the usual velocity of light. Poincaré applied the calculation in a recoil process and reached at the conclusion in the form mv = (E/c^2)c. From the viewpoint of unit analysis, E/c^2 takes on the role of a "mass" number associated with radiation. It yields E=mc^2.

(vi) Olinto De Pretto
An Italian Industrialist Olinto De Pretto [5] suggested E=mc^2, in concrete way. Firstly this article was published on June 16, 1903. Second time on February 27, 1904 the same was published in the Atti of the Reale Instituto Veneto di Scienze. Thus De Pretto published E=mc^2 about one and half year before. In 1921 De Pretto was shot dead by a woman over a business dispute. When De Pretto was killed he was trying to publish the complete book of his scientific ideas. This paper is in Italian; hence it remained away from accessibility of wider scientific community. However Einstein was affluent in Italian language also.
(v) F. Hasenöhrl
In 1904 F. Hasenöhrl [6,7 ], gave first derived expression for mass-energy conversion. He investigated a system composed of a hollow enclosure filled with "heat" radiations and wanted to determine the effect of pressure due to radiations. His calculations lead him to conclude that
"to the mechanical mass of our system must be added an apparent mass which is given by
m = (8/3)E/c^2"
where E is the energy of the radiation. Further in later paper he maintained that improve result for mass exchanged is
m = (4/3)E/ c^2"
Ebenezer Cunningham [9] in 1914 in his book The Principles of Relativity showed that F. Hasenöhrl, has made a slight error in his calculations. F. Hasenöhrl, did not take characteristics of the shell properly. If errors are removed then
m (mass exchanged) = E/c^2
or E = (mass exchanged) c^2
This is the same result as quoted by Einstein. It implies that E=mc^2 is contained in F. Hasenöhrl’s, analysis. Moreover Hasenöhrl’s work was published in the same journal in which Einstein’s method to derive E=mc^2 was published one year later.
(vi) Albert Einstein
In 1905, Einstein [10] derived L = mc^2, and then speculated from here E=mc^2, analogously without actual proof. Einstein derived already existing E=mc^2, strangely did not acknowledge his predecessors like de Pretto and Hasenöhrl. Both have suggested E=mc^2 just one and half year before Einstein’s derivation. However two years after i.e. 1907 when Max Plank [8] derived E=mc^2 independently, Planck acknowledged derivation of Einstein. Planck even pointed out the conceptual and mathematical limitations of Einstein’s method of derivation..
(a) Although Einstein started to derive E=mc^2 using relativistic variation of light energy as in Eq.(2), yet he derived final results under classical condition. Einstein interpreted the results using Binomial Theorem which is applicable if v<<c.

(b) Einstein never considered the any Relativistic Increase in Mass of body.
ThE equation of Relativistic Increase In Mass was first justified by Kaufman [11] in 1900.
Further Einstein speculated E=mc^2 for all energies from E=mc^2 without justifying that eq.(2) i.e. holds good for sound, heat, chemical , electrical energy etc. If eq.(2) holds good for sound and heat energies, then E=mc^2 will be analogously transformed as
Sound energy = E=mc^2 (3)
or Every type of energy = E=mc^2 (4)

(vii) Max Planck
In 1907, Planck [8] made an in-depth investigation of the energy "confined" within a body, but he did not use Einstein approach at all. Plank presented his findings in
Planck derived an expression
m-M= E/c2
and interpreted that
” The inertia mass of body is altered by absorption or emission of heat energy. The increments of mass of body are equal to heat energy divided by square of speed of light”
Then in a footnote at page 566 Planck writes, "Einstein has already drawn essentially the same conclusions”. Planck maintained Einstein derivation as approximation.
(ix) Recent developments.
In 1907 Planck [8] even pointed out the conceptual and mathematical limitations of Einstein’s derivation. In 1952, H E Ives [12] stressed that Einstein’s derivation of the formula E=mc^2 is fatally flawed because Einstein set out to prove what he assumed.
Sharma [13] in 2003 extended E=mc^2 to E =Ac^2m, where A is conversion co-efficient and can be equal, less or more than one, depending upon inherent characteristics of conversions process in nature. The value of A is consistent with concept of proportionality factor existing since centuries. Energy emitted in celestial events Gamma Ray Bursts (most energetic events after Big Bang) is 10^ 45 Joule/s. It can be explained with value of A equal to 2.57x10^18. Similar is the case of Quasars. Like wise kinetic energy of the fission Fragments of U^235 or Pu^239 is found 20-60 MeV less than Q-value ( 200MeV), Bakhoum [14] The similar deviations in experimental results are also quoted by Hambsch [15], Thiereus [16] etc. It can be explained with value of A less than one. Till date E=mc^2 is not confirmed in chemical reaction due to technical reasons, but regarded as true.
Also a particle Ds (2317) discovered at SLAC [17] has been found to have mass lower than current estimates based upon E=mc^2. Incidentally, there are proposals for both theoretical and experimental variations (increase or decrease) in value of c [18-19]; as fine structure constant is reported to be increasing over cosmological timescales, implying slowing down of speed of light, c. The proposals for variations of speed of light definitely affect status of E =mc2, indirectly.
2.0 Einstein and priority of E=mc^2
Einstein did not mention Hasenöhrl’s work (who gave first derived expression for mass-energy equation) in any of his paper on this subject from 1900 - 1909. However Hasenöhrl has published in 1904 the paper in the same very journal in which Einstein later published his derivation of E=mc^2 in 1905.
Einstein [20] applied his E=mc^2 derivation in 1906. In this paper he gave reference of Poincaré' s work [3, 4]. Einstein gave credit to Poincaré for mass energy equivalence at least for electromagnetic radiations.
But, even with Planck's complete derivation and this Poincaré acknowledgment, Einstein later refused to accept any other priority for this notion. Stark [21] stated that Planck gave first derivation of E=mc^2, in fact Planck and Stark were convinced that Einstein derivation of E=mc^2 is inconsistent. Then Einstein [22] wrote Stark on 17 Feb 1908, “I was rather disturbed that you do not acknowledge my priority with regard to the connection between inertial mass and energy.” Max Born [23], co-originator of Quantum Mechanics stated, "The striking point is that it contains not a single reference to previous literature”.
Einstein [24] in 1907 spelled out his views on plagiarism: "It appears to me that it is the nature of the business that what follows has already been partly solved by other authors. Despite that fact, since the issues of concern are here addressed from a new point of view, I am entitled to leave out a thoroughly pedantic survey of the literature..."



The above is embarassing . I have read your paper, it is all wrong. You make a mistake right at the beginning (eq 13) when you miss the fact that there should be momentum change due to particle recoil. You misattribute the change in energy to "mass increase (!) after radiation".
This is not only theoretically incorrect but also experimentally.
An the tone towards Einstein is so arrogant, it is disgusting.
 
  • #38
Nommos Prime (Dogon) said:
Light is.
The speed of light IS NOT a constant (and NEVER has been).

pseudo-physics.

(i guess if you change you unit length from a meter to a foot, the numerical value of c will change.)
 
  • #39
This thread doesn't deserve to be revived, even to point out the glaring psuedoscience. (Under our current policy, the initial post would have been tagged and bagged immediately.)
 

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