[General] Position
John Duffield
johnduffield at btconnect.com
Thu Apr 23 09:17:09 PDT 2015
Martin:
When you lift that electron, you do work on it. You add energy to it. And
the mass of a body is a measure of its energy-content
<https://www.fourmilab.ch/etexts/einstein/E_mc2/www/> . 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
<http://pedram.leilabady.people.cpcc.edu/EOC_Solutions_pdf/Ch42/EOC_Solution
_42_43.pdf> mass decrease that occurs when the electron and proton form a
hydrogen atom.
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 any 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
left the building. 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 mass varies with gravitational potential.
I look forward to being able to lubricate your intellect with copious
alcohol in order to persuade you about the above.
Regards
John D
From: General
[mailto:general-bounces+johnduffield=btconnect.com at lists.natureoflightandpar
ticles.org] On Behalf Of Mark, Martin van der
Sent: 23 April 2015 16:37
To: Nature of Light and Particles - General Discussion
Subject: Re: [General] Position
Oh John,
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.
Rest mass is invariant. Period. That is why it is a very useful, no, an
indispensable concept!
So the rest of what you say is quite right, but confusion is there again
.
Sorry for producing the extra confusion,
Cheers, Martin
Dr. Martin B. van der Mark
Principal Scientist, Minimally Invasive Healthcare
Philips Research Europe - Eindhoven
High Tech Campus, Building 34 (WB2.025)
Prof. Holstlaan 4
5656 AE Eindhoven, The Netherlands
Tel: +31 40 2747548
From: General
[mailto:general-bounces+martin.van.der.mark=philips.com at lists.natureoflighta
ndparticles.org] On Behalf Of Mark, Martin van der
Sent: donderdag 23 april 2015 17:24
To: Nature of Light and Particles - General Discussion
Subject: Re: [General] Position
Dear John,
Thanks but you are wrong.
Its weight increases in a strong gravitational field, not its mass.
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
..
Cheers, Martin
Regards, Martin
Dr. Martin B. van der Mark
Principal Scientist, Minimally Invasive Healthcare
Philips Research Europe - Eindhoven
High Tech Campus, Building 34 (WB2.025)
Prof. Holstlaan 4
5656 AE Eindhoven, The Netherlands
Tel: +31 40 2747548
From: General
[mailto:general-bounces+martin.van.der.mark=philips.com at lists.natureoflighta
ndparticles.org] On Behalf Of John Duffield
Sent: donderdag 23 april 2015 16:53
To: 'Nature of Light and Particles - General Discussion'
Subject: Re: [General] Position
Martin:
“Only the rest mass m0 is the invariant of a particle’s (or closed system’s)
motion”.
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
<http://www.astro.ucla.edu/~wright/deflection-delay.html> deflected twice as
much as matter :
When you’ve dissipated the kinetic energy, the rest mass is reduced, and you
have a <http://en.wikipedia.org/wiki/Binding_energy#Mass-energy_relation>
mass deficit. 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
511keV/c ². A descending photon only appears to have gained energy because
you lose energy when you descend.
Regards
John D
From: General
[mailto:general-bounces+johnduffield=btconnect.com at lists.natureoflightandpar
ticles.org] On Behalf Of Mark, Martin van der
Sent: 23 April 2015 15:13
To: Nature of Light and Particles - General Discussion
Subject: Re: [General] Position
Dear Richard,
Thank you for calling “light is heavy” excellent and also thank you for
presenting the example of being confused.
Perhaps it proves that the paper is not so excellent after all in getting
the idea across.
See my comments in blue
.
Dr. Martin B. van der Mark
Principal Scientist, Minimally Invasive Healthcare
Philips Research Europe - Eindhoven
High Tech Campus, Building 34 (WB2.025)
Prof. Holstlaan 4
5656 AE Eindhoven, The Netherlands
Tel: +31 40 2747548
From: General
[mailto:general-bounces+martin.van.der.mark=philips.com at lists.natureoflighta
ndparticles.org] On Behalf Of Richard Gauthier
Sent: woensdag 22 april 2015 19:33
To: Nature of Light and Particles - General Discussion
Subject: Re: [General] Position
Hello John D and John W. and others,
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,
Wrong. They will receive a net extra impulse from the opposite walls of the
box (p=mc with c constant), as you say yourself:
but their total momentum p=gamma mv increases as does their total energy
E=gamma mc^2.
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
E = mc^2 = sqrt[m0^2c^4 + gamma^2 m0^2 v^2 c^2 ]
So that
E=m0c^2 sqrt[1+gamma^2 v^2/c^2]
Which for v << c is
E = m0c^2 + ½ m0v^2 +
.
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.
Note to David: It is all about physics but I express it in mathematics since
that is the language of physics.
In current usage in relativistic dynamics, the word “mass” and the letter
m are taken to mean “rest mass”.
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.
As you know, this is an invariant of a particle’s motion. It doesn’t
increase with a particle’s speed.
Correct
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.
Correct, and that energy is its mass times c^2
Saying that a photon has mass but not rest mass seems to me a statement more
about semantics than physics.
Richard, from the above it should now be clear that it is not semantics.
Why not just say a photon has energy?
You are contradicting yourself, it has mass as can be concluded from the
fact that the photon is attracted by gravity. It must have mass,
gravitational mass so to speak.
For what it’s worth, see http://en.wikipedia.org/wiki/Invariant_mass and
http://en.wikipedia.org/wiki/Mass
<http://en.wikipedia.org/wiki/Mass%E2%80%93energy_equivalence>
–energy_equivalence .
Thanks for the links.
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.
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.
Our task as scientists is to shift our perspective on nature such that
everything fits exactly. No more, no less.
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.
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.
It is time to fine-tune your shift of perspective and I hope may comments
will help you and others.
Richard
On Apr 22, 2015, at 6:36 AM, John Duffield <johnduffield at btconnect.com
<mailto:johnduffield at btconnect.com> > wrote:
Richard:
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
<https://www.fourmilab.ch/etexts/einstein/E_mc2/www/> Einstein’s paper. All
of it. And hen it isn’t there any more. Do read
<http://www.tardyon.de/mirror/hooft/hooft.htm> light is heavy. It’s very
simple really.
Regards
John D
From: General
[mailto:general-bounces+johnduffield=btconnect.com at lists.natureoflightandpar
ticles.org] On Behalf Of John Williamson
Sent: 22 April 2015 08:40
To: Nature of Light and Particles - General Discussion
Subject: Re: [General] Position
Hello,
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.
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.
Regards, John.
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