Einstein did not derive E =mc2 first

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Icarus said:
On the constancy of c, there are some concerns to be brought up:

1) Constant with respect to what? Relativity requires c to be constant with respect to observer, but not with respect to space or time. Relativity (Special or General) only says that if you have two observers at the same event, they will measure the same speed for light, regardless of any relative motion. It does not require that they measure the same speed as observers at other events.

This is a point almost entirely ignored (and very seldom even realized). While extensive evidence supports special relativity and the constancy of light with respect to observer, none of this implies that the speed of light is also constant with respect to spacetime event. The speed in other galaxies or around other stars may differ significantly from what it is here. The speed may have been different in earth's past than it is now. Our best evidence for constancy with respect to event is simply that the error intervals for all measurements made so far overlap. (Some have suggested that early measurements show a different value - but those measurement were so inaccurate that the difference is more readily explanable as simple error). By Fermat, changes in the value of c along a light ray's path should produce bending, so presumably, if the value of c varies in space, we should see lensing affects. Might some of the "gravitational" lensing seen actually be caused by variation in "c"?
Observation is a spacetime event.

Show me that conjecture of Fermat's(i think i might have heard something simliar but i ahve not read it, and will not be able to reply to it accurately until having done so) and its support.

You can only to that conclusion about gravitational lensing through a gross misunderstanding and misuse of the relevant equations. If you maintain your frame of reference you will get no such possible interpretation, because you cannot get a variational speed of light in the same equation if you do. Gravitational lensing is the result of a curved geometry and the lgiht ray following the path of least action, the solution to the Euler-Lagrange equation, namely, a geodesic.
 

Nereid

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OneEye said:
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 think you may be referring to alpha, the fine structure constant.

There've been a number of papers reporting some small variation over cosmological time, but also several reporting none. Needless to say, the observations required are extensive, and not that easy to do, even with the VLT or Keck.

Among the best astronomical observations is http://www.eso.org/outreach/press-rel/pr-2004/pr-05-04.html [Broken] on this, as well as some older discussion. This reports new limits on any time variation of alpha (i.e. it doesn't seem to vary by more than ~0.6 parts per million, over ~10 billion years).
 
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The main point is that Einstein derived general relativity over a period of years - other people had the chance to do it in this time but did not. Einstein even changed the way maths was done ( his summation convention for example - try getting by without it).Einstein made a very abstract and difficult piece of mathematics represent the
real world and no doubt made it easier for people to accept the schrodinger equation which is also quite an abstract idea.
 
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OneEye said:
It seems to me that the view of what constitutes a "ghost measurement" might well be merely a matter of prejudice. Without a scalpel, which view is to be taken as correct?
No prejudice - simple scalpel: A "ghost measurement" is any quantity that cannot be actually measured - not just because no one is available to measure it, or the right equipment is unavailable, but because it is fundamentally unmeasurable. My best guess at what your comments meant suggested you were refering to such quantities - I see no point in speculating about them because even if they do have some existance that can NEVER be confirmed experimentally and have no effect on us anyway. Likely, I am wrong about what your comments meant. Would you please explain what you mean by "the ontological view" & "the phenomenological view" of relativity? I've tried to decipher it from the meanings of the these two words, but am at a loss.

franznietzsche said:
Observation is a spacetime event.
No - observation takes place at spacetime events. The word "event" in relativity simple refers to a point of spacetime - "point" itself being too much associated with space alone.

franznietzsche said:
Show me that conjecture of Fermat's(i think i might have heard something simliar but i ahve not read it, and will not be able to reply to it accurately until having done so) and its support.

You can only to that conclusion about gravitational lensing through a gross misunderstanding and misuse of the relevant equations. If you maintain your frame of reference you will get no such possiblinterpretation, because you cannot get a variational speed of light in the same equation if you do. Gravitational lensing is the result of a curved geometry and the lgiht ray following the path of least action, the solution to the Euler-Lagrange equation, namely, a geodesic.
Fermat's Principle, which I refered to, is: The path light follows between two points is the one that takes the least time. It was this principle that inspired Lagrange to invent the concept of "action" and state the more general principle (the heart of his formulation of mechanics) that the path of any system between two states will be the one with least action. So if you are unfamiliar with the idea, I would suggest not refering to it in your own arguments! :wink:

As for the rest, please reread my post, and note that I made NO conclusions about gravitational lensing - other than to say that gravitational lensing does not involve variations in c! As for that, you could consider variations in c as being a gravitational effect (as c comes from the spacetime metric), but for this discussion it makes sense to separate it from the more common idea of gravitational lensing (caused by mass-distortion of spacetime).
 
Speed Of Light Fallacies...

OneEye makes some brilliant observations regarding light-speed (Constancy) fallacies.

The KEY is that C is only constant in a VACUUM.

Real Vacuums (in the Universe are extremely Rare). Space is not a vacuum (it is littered with matter). Earth is certainly not a vacuum.

I would contend that Vacuums ONLY EXIST at the heart of ALL matter, and in 4-11 dimensions (My "Vacuum Heart" Theory, again). Light-speed can be manipulated by gravitational effects...
 

selfAdjoint

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A photon that reaches us from a distant galaxy has not been scattered by any matter in between. That photon has travelled 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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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, refering 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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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!)
 
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OneEye said:
1) c is variable under general relativity.
And I thought that in general relativity, ds2 = 0 for light.
 
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Nereid

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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 [Broken] (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 [Broken], 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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russ_watters

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shrumeo said:
isn't a vacuum the only medium "through" which light travels, really?
Yes. The phrase "light traveling through a medium" is misleading.
 
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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 acknowledgement, 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.
 

rbj

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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.)
 

Doc Al

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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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