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<p class="MsoNormal"><span style="color:black">Dear John,</span><o:p></o:p></p>
<p class="MsoNormal">You are very right about what you say, but you miss the point I try to make.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Perhaps I now see where some of the confusion is,<span style="color:black"> and Richard is right in some sense about semantics.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black">It is the word REST in rest mass that disturbs you, I presume.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black">I am usually only talking about the physics and do not care a lot about names. Now this is the point, perhaps:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black">In <b>special relativity</b> the inertia of a body, which is usually seen as a structureless thing, has one
<b>invariant property</b> associated to it and historically this is called <b>rest mass
</b>and denoted by<b> m0</b>. This makes intuitively immediate sense in case of point particles or hard spheres when no gravitation is considered. But in
<b>general relativity</b> we do consider gravitation and now it is immediately clear that an electron lying at rest at the second floor must have a different energy and hence a different mass from one, also at rest, at ground level. So the term rest mass does
not properly translate from special to general relativity. Perhaps better we should call
<b>m0</b> the <b>invariant mass, </b>it is the number you find in tables telling you that it is 9.1x10^-31 kg or 0.511 MeV/c^2.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:black">There is another reason why the term rest mass may be confusing, it is because inside any body or object or particle or box there is usually a lot of kinetics. Doesn’t matter, as long as we are having a closed
system. <o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:black">Richard and John, please read what I wrote before and replace rest mass by invariant mass and see if it eliminates the problem.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black">Hope to hear from you soon,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black">Very best, Martin</span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<div>
<p class="MsoNormal"><span lang="DE" style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">Dr. Martin B. van der Mark</span><span lang="DE" style="color:navy"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">Principal Scientist, Minimally Invasive Healthcare</span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:navy"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:navy"> <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">Philips Research Europe - Eindhoven</span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:navy"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">High Tech Campus, Building 34 (WB2.025)</span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:navy"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">Prof. Holstlaan 4</span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:navy"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">5656 AE Eindhoven, The Netherlands</span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:navy"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">Tel: +31 40 2747548</span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> General [mailto:general-bounces+martin.van.der.mark=philips.com@lists.natureoflightandparticles.org]
<b>On Behalf Of </b>John Duffield<br>
<b>Sent:</b> donderdag 23 april 2015 18:17<br>
<b>To:</b> 'Nature of Light and Particles - General Discussion'<br>
<b>Subject:</b> Re: [General] Position<o:p></o:p></span></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-family:"Arial","sans-serif";color:#0D0D0D">Martin:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-family:"Arial","sans-serif";color:#0D0D0D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-family:"Arial","sans-serif";color:#0D0D0D">When you lift that electron, you do work on
<i>it</i>. You add energy to <i>it</i>. And </span><span lang="EN-GB" style="font-family:"Arial","sans-serif";color:blue"><a href="https://www.fourmilab.ch/etexts/einstein/E_mc2/www/">the mass of a body is a measure of its energy-content</a></span><span lang="EN-GB" style="font-family:"Arial","sans-serif";color:#0D0D0D">.
You added energy to it, so you increased its mass. The fact that you do the same with another electron and they still balance on your scale doesn’t mean their mass didn’t increase. In similar vein when they fall down and you dissipate the kinetic energy, that
mass deficit is not some fiction. Nor is the 13.6ev <a href="http://pedram.leilabady.people.cpcc.edu/EOC_Solutions_pdf/Ch42/EOC_Solution_42_43.pdf">
<span style="color:#0D0DFF">mass decrease</span></a> that occurs when the electron and proton form a hydrogen atom. <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-family:"Arial","sans-serif";color:#0D0D0D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-family:"Arial","sans-serif";color:#0D0D0D">Note that when you lift the electron, conservation of momentum applies, but the Earth doesn’t move in any discernible way. So the energy you expended wasn’t shared
equally. To all extents and purposes you didn’t do <i>any</i> work on the Earth. Thereafter the electron’s potential energy isn’t in the Earth, or in the space between the Earth and the electron. It isn’t in the gravitational field, it’s in the electron. You
surely know this because you know that if you give the electron an upward lift of 11.2km/s, the kinetic energy is converted into potential energy, but the electron has escape velocity. It leaves the Earth, and wanders off into space. The electron has
<i>left the building</i>. It has gone forever, taking all that energy with it. The original 511keV and the 11.2km/s worth of kinetic energy have gone. And you surely know that to balance the books, an electron at rest in free space has a greater mass than
an electron at rest at the surface of the Earth. You surely know that <i>mass varies with gravitational potential.</i> <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-family:"Arial","sans-serif";color:#0D0D0D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-family:"Arial","sans-serif";color:#0D0D0D">I look forward to being able to lubricate your intellect with copious alcohol in order to persuade you about the above. <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-family:"Arial","sans-serif";color:#0D0D0D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-family:"Arial","sans-serif";color:#0D0D0D">Regards<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-family:"Arial","sans-serif";color:#0D0D0D">John D
<u><o:p></o:p></u></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif"">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif""> General [<a href="mailto:general-bounces+johnduffield=btconnect.com@lists.natureoflightandparticles.org">mailto:general-bounces+johnduffield=btconnect.com@lists.natureoflightandparticles.org</a>]
<b>On Behalf Of </b>Mark, Martin van der<br>
<b>Sent:</b> 23 April 2015 16:37<br>
<b>To:</b> Nature of Light and Particles - General Discussion<br>
<b>Subject:</b> Re: [General] Position<o:p></o:p></span></p>
</div>
</div>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Oh John,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">what I forgot to say, of course, is that you are right about the fact that the electron does gain potential energy when you lift it, but that is the same thing
for the 1kg from Paris. <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Rest mass is invariant. Period. That is why it is a very useful, no, an indispensable concept!<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">So the rest of what you say is quite right, but confusion is there again….<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Sorry for producing the extra confusion,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Cheers, Martin<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<div>
<p class="MsoNormal"><span lang="DE" style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">Dr. Martin B. van der Mark</span><span lang="DE" style="color:navy"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">Principal Scientist, Minimally Invasive Healthcare</span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:navy"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:navy"> <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">Philips Research Europe - Eindhoven</span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:navy"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">High Tech Campus, Building 34 (WB2.025)</span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:navy"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">Prof. Holstlaan 4</span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:navy"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">5656 AE Eindhoven, The Netherlands</span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:navy"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">Tel: +31 40 2747548</span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p></o:p></span></p>
</div>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> General [<a href="mailto:general-bounces+martin.van.der.mark=philips.com@lists.natureoflightandparticles.org">mailto:general-bounces+martin.van.der.mark=philips.com@lists.natureoflightandparticles.org</a>]
<b>On Behalf Of </b>Mark, Martin van der<br>
<b>Sent:</b> donderdag 23 april 2015 17:24<br>
<b>To:</b> Nature of Light and Particles - General Discussion<br>
<b>Subject:</b> Re: [General] Position<o:p></o:p></span></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Dear John,</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Thanks but you are wrong.
</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Its
<b>weight</b> increases in a strong gravitational field, not its <b>mass</b>.</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Note: Masses should be determined by weighing on a balance scale: a calibrated mass of, say 1kg made of platinum and kept in Paris (or something like that)
is always going to give the same mass, but may have a different weight according to the planet you are on or the height you are at. This is how it works already between equator and north pole of the earth…..</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Cheers, Martin</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Regards, Martin</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
<div>
<p class="MsoNormal"><span lang="DE" style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">Dr. Martin B. van der Mark</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">Principal Scientist, Minimally Invasive Healthcare</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:navy"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">Philips Research Europe - Eindhoven</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">High Tech Campus, Building 34 (WB2.025)</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">Prof. Holstlaan 4</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">5656 AE Eindhoven, The Netherlands</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">Tel: +31 40 2747548</span><o:p></o:p></p>
</div>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> General [<a href="mailto:general-bounces+martin.van.der.mark=philips.com@lists.natureoflightandparticles.org">mailto:general-bounces+martin.van.der.mark=philips.com@lists.natureoflightandparticles.org</a>]
<b>On Behalf Of </b>John Duffield<br>
<b>Sent:</b> donderdag 23 april 2015 16:53<br>
<b>To:</b> 'Nature of Light and Particles - General Discussion'<br>
<b>Subject:</b> Re: [General] Position</span><o:p></o:p></p>
</div>
</div>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:black">Martin:</span><o:p></o:p></p>
<p class="MsoNormal"><i><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span></i><o:p></o:p></p>
<p class="MsoNormal"><i><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#0070C0">“Only the rest mass m0 is the invariant of a particle’s (or closed system’s) motion”.</span></i><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#0D0D0D">Chuckle, at this juncture I just have to say it for the benefit of the group: invariant mass varies! The electron’s rest mass increases when you
lift it up. Then when you drop it, some of the internal kinetic energy is converted into external kinetic energy, and the electron falls down. Simplify your electron to light going round a square path, note that only the horizontals bend, and that light is
<a href="http://www.astro.ucla.edu/~wright/deflection-delay.html"><span style="color:#0D0DFF">deflected twice as much as matter</span></a> :</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#0D0D0D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:black"><img border="0" width="120" height="92" id="Picture_x0020_1" src="cid:image001.jpg@01D07E13.EEC990D0"></span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#0D0D0D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#0D0D0D">When you’ve dissipated the kinetic energy, the rest mass is reduced, and you have a
<a href="http://en.wikipedia.org/wiki/Binding_energy#Mass-energy_relation"><span style="color:#0D0DFF">mass deficit</span></a>. Note that in an extreme situation something must surely happen, as per Winterberg’s paper attached - I’m confident that the general
sense of this is correct. Also note that when a photon descends, it doesn’t really get blueshifted. It’s all kinetic energy, conservation of energy applies. Send a 511keV electron into a black hole, and the black hole mass increases by
</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#0D0D0D">511keV/c</span><span lang="EN-GB"> ²</span><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#0D0D0D">. A descending
photon only appears to have gained energy because you lose energy when you descend.</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#0D0D0D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#0D0D0D">Regards</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#0D0D0D">John D</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
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<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif"">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif""> General [<a href="mailto:general-bounces+johnduffield=btconnect.com@lists.natureoflightandparticles.org">mailto:general-bounces+johnduffield=btconnect.com@lists.natureoflightandparticles.org</a>]
<b>On Behalf Of </b>Mark, Martin van der<br>
<b>Sent:</b> 23 April 2015 15:13<br>
<b>To:</b> Nature of Light and Particles - General Discussion<br>
<b>Subject:</b> Re: [General] Position</span><o:p></o:p></p>
</div>
</div>
<p class="MsoNormal"><span lang="EN-GB"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-family:"Calibri","sans-serif";color:#0070C0">Dear Richard,</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-family:"Calibri","sans-serif";color:#0070C0">Thank you for calling “light is heavy” excellent and also thank you for presenting the example of being confused.</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-family:"Calibri","sans-serif";color:#0070C0">Perhaps it proves that the paper is not so excellent after all in getting the idea across.</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-family:"Calibri","sans-serif""> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-family:"Calibri","sans-serif";color:#0070C0">See my comments in blue….</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
<div>
<p class="MsoNormal"><span lang="DE" style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">Dr. Martin B. van der Mark</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">Principal Scientist, Minimally Invasive Healthcare</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:navy"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">Philips Research Europe - Eindhoven</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">High Tech Campus, Building 34 (WB2.025)</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">Prof. Holstlaan 4</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">5656 AE Eindhoven, The Netherlands</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">Tel: +31 40 2747548</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> General [<a href="mailto:general-bounces+martin.van.der.mark=philips.com@lists.natureoflightandparticles.org">mailto:general-bounces+martin.van.der.mark=philips.com@lists.natureoflightandparticles.org</a>]
<b>On Behalf Of </b>Richard Gauthier<br>
<b>Sent:</b> woensdag 22 april 2015 19:33<br>
<b>To:</b> Nature of Light and Particles - General Discussion<br>
<b>Subject:</b> Re: [General] Position</span><o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">Hello John D and John W. and others,<o:p></o:p></p>
<div>
<p class="MsoNormal"> I read “Light is Heavy” many years ago and found it excellent. I don’t think it affects my argument. The energy of a set of photons has “rest mass” when they are confined in a box or confined by self-circulation. In its center-of-mass
(center-of-energy?) frame the total momentum p of a set of confined photons equals zero and so the rest mass m of this set of photons with total energy Etotal equals m= Etotal/c^2, as seen from the relativistic energy-momentum equation E^2=p^2 c^2 + m^2 c^2,
which also applies to total E, p and m of a system of particles. If a box of photons is moving, the total mass m of these photons doesn’t change,
<o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#0070C0">Wrong. They will receive a net extra impulse from the opposite walls of the box (p=mc with c constant), as you say yourself:
</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal">but their total momentum p=gamma mv increases as does their total energy E=gamma mc^2. <o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#0070C0">But p is not mv , the velocity of the photons is and remains c at all times, v is merely the velocity of the box. The momentum increases because the mass increases.
This is true for ALL physical processes, in fact. A car moving at velocity v has an additional mass compared to its mass at rest (the rest mass m0) exactly equal to its kinetic energy divided by c^2: Ekin/c^2 = m which at low velocity (the non-relativistic
limit) is very nearly equal to ½ mv^2. So</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#0070C0"> </span><o:p></o:p></p>
<p class="MsoNormal"><span lang="NL" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#0070C0">E = mc^2 = sqrt[m0^2c^4 + gamma^2 m0^2 v^2 c^2 ]</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#0070C0">So that</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="NL" style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#0070C0">E=m0c^2 sqrt[1+gamma^2 v^2/c^2]</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#0070C0">Which for v << c is</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#0070C0">E = m0c^2 + ½ m0v^2 + ….</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#0070C0"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#0070C0">Any form of energy is massive ; The mass m is the most universal form of energy, it is the essence of energy and it gravitates like a mass m.</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#0070C0"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#0070C0">Note to David: It is all about physics but I express it in mathematics since that is the language of physics.</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="color:#1F497D"> </span><o:p></o:p></p>
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<div>
<p class="MsoNormal"> In current usage in relativistic dynamics, the word “mass” and the letter m are taken to mean “rest mass”.
<o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#0070C0">Some people do that. It is a mistake because it leads to confusion and has been introduced as a result of previous confusion. Only the rest mass m0 is the invariant
of a particle’s (or closed system’s) motion.</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal">As you know, this is an invariant of a particle’s motion. It doesn’t increase with a particle’s speed.
<o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#0070C0">Correct</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal">In this sense the mass of a single photon is zero, since it has no rest mass. But a single photon is still attracted by a gravitational field, since the photon carries energy.
<o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#0070C0">Correct, and that energy is its mass times c^2</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal">Saying that a photon has mass but not rest mass seems to me a statement more about semantics than physics.
<o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#0070C0">Richard, from the above it should now be clear that it is not semantics.</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal">Why not just say a photon has energy? <o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#0070C0">You are contradicting yourself, it has mass as can be concluded from the fact that t</span><span style="font-family:"Calibri","sans-serif";color:#0070C0">he
photon is attracted by gravity. It must have mass, gravitational mass so to speak.</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal">For what it’s worth, see <a href="http://en.wikipedia.org/wiki/Invariant_mass">http://en.wikipedia.org/wiki/Invariant_mass</a> and <a href="http://en.wikipedia.org/wiki/Mass%E2%80%93energy_equivalence">http://en.wikipedia.org/wiki/Mass–energy_equivalence</a> .<o:p></o:p></p>
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<p class="MsoNormal"><span style="color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#0070C0">Thanks for the links.</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
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<div>
<p class="MsoNormal"> If an electron is composed of a circulating photon there is nothing “at rest” in a “resting” electron. The term “rest mass” of an electron may be dispensed with in the future by replacing it with Emin/c^2 = 0.511 MeV/c^2 (as is generally
done now in particle physics) where Emin is the minimum total energy of a free electron.<o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#0070C0">Wrong. The electron as a whole has a center of mass that can be stationary, all dynamics happening inside. Note that it ( it = the particle, the whole thing
including boundaries or stabilizing forces, for example photon plus box) may be shaking about at the Compton or Zitterbewegung frequency. This random or periodic zero-point motion (by the book, quite a natural thing to have for a quantum mechanical object)
is averaged out by a proper weighing experiment if one wants to know the total mass (being the whole energy). Remember, that energy is subject to the uncertainty principle with the length of time you measure it: The precise mass can be determined only if one
averages over many cycles.</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:"Calibri","sans-serif";color:#0070C0"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-family:"Calibri","sans-serif";color:#0070C0">Our task as scientists is to shift our perspective on nature such that everything fits exactly. No more, no less.
</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-family:"Calibri","sans-serif";color:#0070C0">You are one of the brave that have tried to do so, and you have been able to make a big step in the right direction, I believe.</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-family:"Calibri","sans-serif";color:#0070C0">This is why I put my precious time into this answer. However, some further tuning is required because your present point of view contradicts itself as well as reality. This
true for the above as well as for the charged photon concept. Again, I am not saying it is all wrong, but there is a fatal misfit in places.</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-family:"Calibri","sans-serif";color:#0070C0">It is time to fine-tune your shift of perspective and I hope may comments will help you and others.</span><o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
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<div>
<p class="MsoNormal"> Richard<o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
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<p class="MsoNormal">On Apr 22, 2015, at 6:36 AM, John Duffield <<a href="mailto:johnduffield@btconnect.com">johnduffield@btconnect.com</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:"Calibri","sans-serif"">Richard:</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:"Calibri","sans-serif""> </span><o:p></o:p></p>
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<div>
<p class="MsoNormal"><span style="font-family:"Calibri","sans-serif"">IMHO photon momentum is a measure of resistance to change-in-motion for a wave moving linearly at c, whilst electron mass is a measure of resistance to change-in-motion for a wave going round
and round at c. In a box of its own making. And when you open one box with another in electron-positron annihilation, each is a radiating body that loses mass, just like<span class="apple-converted-space"> </span><a href="https://www.fourmilab.ch/etexts/einstein/E_mc2/www/"><span style="color:purple">Einstein’s
paper</span></a>. All of it. And hen it isn’t there any more. Do read<span class="apple-converted-space"> </span><a href="http://www.tardyon.de/mirror/hooft/hooft.htm"><span style="color:purple">light is heavy</span></a>. It’s very simple really.<span class="apple-converted-space"> </span></span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:"Calibri","sans-serif""> </span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:"Calibri","sans-serif"">Regards</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:"Calibri","sans-serif"">John D</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
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<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif"">From:</span></b><span class="apple-converted-space"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif""> </span></span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif"">General
[<a href="mailto:general-bounces+johnduffield=btconnect.com@lists.natureoflightandparticles.org">mailto:general-bounces+johnduffield=btconnect.com@lists.natureoflightandparticles.org</a>]<span class="apple-converted-space"> </span><b>On Behalf Of<span class="apple-converted-space"> </span></b>John
Williamson<br>
<b>Sent:</b><span class="apple-converted-space"> </span>22 April 2015 08:40<br>
<b>To:</b><span class="apple-converted-space"> </span>Nature of Light and Particles - General Discussion<br>
<b>Subject:</b><span class="apple-converted-space"> </span>Re: [General] Position</span><o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">Hello,<br>
<br>
No. this is confusing mass and rest mass. Photons have "mass" by virtue of their energy. They are not massless but rest-massless and this is not the same thing. The popular literature confuses this. If photons were massless they would not be influenced by a
gravitational field. Photons in a box make the box more rest-massive. You can weigh it! Free light cannot be weighed precisely because it is a gon. The box is at rest and whatever is in it it may be considered "at rest" as well. Forced to rest by being in
the box.<br>
<br>
Light confined in a box increases its effective rest mass in just the same way as any other mass-energy would. If the box is sufficiently sturdy then adding an effective number of joules of mass as a gas, as a photon gas or even as temperature would affect
the rest-mass of the box in exactly the same way. The box aquires the properties of whatever is put into it by virtue of those things being confined in the box.<br>
<br>
Regards, John.</span><o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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