Particle creation and annihilation and the remaining fields problem

[heldervelez]

lets simulate this simple experiment:

creation followed by annihilation of 2 equal particles of type P, here named P1 and P2. (*)
assuming the precursors before creation as usual, and also residuals as usual after annihilation.
The question is about the remaining fields, gravitational and/or electromagnetic.

Let 's' = Space and 'f' = Space With Field
(they are physically different, for sure demonstrated by a test particle )


-- Experiment P1
T0 P1 created...: p1 ssssssssss
T1 field expands...: p1 fsssssssss (at c speed)
T2 ...expands...: p1 ffssssssss
T3 P1 annihilated...:...fffsssssss
T4 ... expands...:...sfffssssss
…
-- Experiment P2 (far away of experiment 1, for sake of simplicity)
T0 P2 created...: p2 ssssssssss
T1 field expands...: p2 fsssssssss
T2 ...expands...: p2 ffssssssss
T3 ...expands...: p2 fffsssssss
T4 ...expands...: p2 fffsssssss
T5 ...expands..: p2 fffffsssss
T6 P2 annihilated...:...blackssss
T7 ... expands.:...sblacksss
T8 .... expands:...ssblackss

Being equal the precursors in the creation and the residuals after annihilation on both experiments we have two different 'Space And Field' .

The quantity 'Space And Field' is dependent on particle antiquity.

And so, if the particles are equal in the beginning they must be different in dead, or 'free lunch' is permitted in physics!


(*) assuming, for instance, two photons <-> electron/positron pair, and equal energy on start of both experiments.

What is the correct answer to this physical problem

 

[malawi_glenn]

You mean that the field is left even after the particle has been annihilated?

This is related to the question: if the sun suddenly dissapears, when will the Earth notice?

 

[heldervelez]

After the source of gravity/electromegnetic field has vanished the field already present in the space, continues propagating, at c speed.
Fields don't get annihilated, by no means.
And even without the presence of the source they can perform work on any test particle.
As noted in the post, the account of 'space with field' is different on both experiments, and as they are physical realities, they must also be accountable on net energy balance.
Usually on learning, and teaching, the annihilation and creation of particles, the problematic associated with the fields is missing from discussion.
I'would like to see some reasoning about this theme in this forum.

a perturbing conclusion is that all particles of type P are not equal.

I presume that you know that if our Sun could 'somehow' suddenly vanish, our Earth will keep moving in a strait line and abandon the regular orbit, at the same instant that the Sun became invisible ( +-8 minutes after 'puff' -- distance Sun-Earth at c speed).
this fact is only partially related to the enunciated question.

the ultimate question is:
all particles of type P are not equal.

my sensibility prevents me from accepting some kind of answer saying that the fields have no energy, because they had to have 'something'. Beeing so, 'something' must be accountable.

 

[malawi_glenn]

Will the gravity disappear at Earth be removed at the same instant as the sun disapears. That was the analogy -> Will field exist, even without a particle/source?

 

[heldervelez]

not at the same instant that 'Sun disapears' but delayed by the propagation of light/ gravity. There is no such thing as 'instant action at distance', c speed is the limit to propagate any physical quantity/effect.

Beeing so, fields does not vanish. They propagate.
As they spread into space at c speed in the presence of the source, also they keep spreading at c speed after extinction of the source, forever .

 

[malawi_glenn]

but the intensity goes to zero... ;-)

I can't really see what your question is, since P2 is annihillated at a later time than P1, thus the fields will be different? I don't know what you are after here.

 

[heldervelez]

of course 'quantity of space with field' at the end of both experiments are different.
lets put side by side a simple representation at the annihilation
let Space be = space without field ; Field = space with field; (field has intensity > 0)
p1-puff/FieldFieldFieldSpaceSpaceSpaceSpace (be space 1-dimmensional, no crisis)
later on ...
p1 not anymore here/SpaceFieldFieldFieldSpaceSpaceSpaceSpace
later on ...
p1 not anymore here/SpaceSpaceFieldFieldFieldSpaceSpaceSpace

p2-puff/FieldFieldFieldFieldFieldFieldSpaceSpaceSpaceSpaceSpace
later on ...
p2 not anymore here/SpaceFieldFieldFieldFieldFieldFieldSpaceSpace
later on ...
p2 not anymore here/SpaceSpaceFieldFieldFieldFieldFieldFieldSpace

as can be seen on this simple 1-dimensional sketch the fields propagate (clearly seen in red) from the point were particles used to be. The source of the field 'mutes' when particles vanished. But there is no vanishing possible on the field already present on space.

at the end of experiment 1 one have ...FieldFieldField... propagating away
at the end of experiment 2 one have ...FieldFieldFieldFieldFieldField... propagating away

we can assume that the precursors of particle p1 and p2 are quantitatively equal (two photons of x energy)
by theory the resultants after the annihilation of both experiments are equal.
beeing so,
with this experiment I have to state
propagating FieldFieldField = propagating FieldFieldFieldFieldFieldField
or else I am prepared to admit that particles after annihilation are'nt just equal on both experiments.

until now I've not seen no clarification on this issue,
and, as you, I'm also perplexed why it seems you cannot understand the problem as it is stated.
...
Everyone assumed that patrticles of type P have allways equal mass.
But it cannot be asserted without proof, and with respect of quantities (mass) the most we can test by experiment is allways within some limits, as small as we can get.

But I do not know of any experiment well succeded to prove that 2 distinct neutrons have equal mass. We can put them as slow as possible, 'freeze' them,..., can we state they are equal ?
... measured half-time is allways within some dispersion.
... and why not the rest-mass of particle neutron be between X-delta, X+delta ?
really, absolutely, and not just the measured value ?

Wikipedia : Neutron mass 1.67492729(28)×10−27 kg
NIST (CODATA) Value 1.674 927 211 x 10-27 kg ,
Standard uncertainty 0.000 000 084 x 10-27 kg ,
Relative standard uncertainty 5.0 x 10-8,
Concise form 1.674 927 211(84) x 10-27 kg ,
(wikipedia has different values from CODATA)

This uncertainity could represent two things:
the allways present uncertitude in the measure thecnique.
AND the possibility, that neutrons have different rest-mass.

And I maintain that not all particles of type P are equal. (at rest, i.e. same energetic condition).

Nobody has to 'believe', we are talking on physics.
Does anyone have any evidence that proves that all neutrons have equal rest-mass?
I suppose you know the answer.

Back to the experiment 1 versus experiment 2, please.
Check the experiments conditions, and pinpoint any error, if possible.

 

[malawi_glenn]

Now I have no idea what you are talking about, and your post is really not structured at all.

Do you for the first know how particles are detected in a particle detector for instance?

 

[heldervelez]

Now I have no idea what you are talking about, and your post is really not structured at all.

Do you for the first know how particles are detected in a particle detector for instance?

If, as you said 'I have no idea what you are talking about' is more reasonable to leave
this discussion. Dont waste any more time, yours and mine.

Someone will understand the question as posted initially.

( By the way, I'm electronic engineer from the IST of Lisbon, 5 years superior study, 54 years old,
and, you know, most problably I don't have a clue about electrons, neutrons, particles, fields, intensities, detectors,... name it,... )

 

[malawi_glenn]

Since I am particle physics student, I only suggested that you perhaps should stress what you think is the paradox/anomaly in your example.

The picture you have drawn is not related to how you detect particles in a detector, you are assuming that the reason for that the different values of the measured field are due to particles beeing annihilated at different time, thus you'll get diffent values. But this is not related to a real physical situation - how you detect particles in a detector.

And then you raised a discussion on how one can "be sure" that two neutrons are equal since you can't really get the same value, is a question that is related to philosophy of science in general. Since it is more symmetric to assume that all neutrons have same rest mass, and the fluctuations are just due to experimental resolution, that position wins over the situation that the neutrons themselves have a intrinsic restmass deviation.

Same holds for your example on particle annihilation along the path of flight, how would this example relate to reality? What is the mechanisms for the annihilation and what is your device for detecting the field?

And just for your information, you don't establish the mass of particles by measure their gravitational interaction, but you probably knew this..

 

[heldervelez]

in the first post I've described a conceptual experiment were detectors are not needed, for sure.
But, conceptual or not, is a physical question, and what I stress, again, is the unexpected result that at annihilation of pairs P1 and pairs P2 they MUST have different content (energy).
I understand that in particle physics, usually disregards to the propagated fields. After all you are 'only' talking about 'particles', not the outside ordinary electro/ /gravitationaly emited fields. In the Feynman diagrams they are ommited.

I'm prepared to discuss the experiment as stated above,
and, as the experiment sugests ,even contrary to our expectations, we cannot say as you did '..it is more symmetric to assume that all neutrons have same rest mass'.

if you are a student, try to check with your teachers, but keep in mind that is extremelly difficult for a theacher to assume that it has no answer.
I found no answer in the theory.
Everyone is assuming all particles of type P are just equal.

In the beginning of experiment (time T0) pair P1 = pair P2 and by the moment of annihilation pair P1 NOT= pair P2.

You call it anomaly/paradox, but I know that it is not so.

 

[NoTime]

As malawi_glenn already pointed out, your question appears similar to the question of "Will the gravitational force experienced by Earth cease to exist at the same instant as the sun disappears".
Since you didn't address the analogy, I'm going to guess that you don't understand that this is an actual question with an undefined answer.
The answers you might get will involve either spacetime geometry response (in GR) or virtual photon/graviton exchange (in a QFT).
This is one (if not the major) underlying reason that there is no unified field theory.
Neither idea would seem to support a need for mass variance between particles of the same type.

 

[granpa]

the remaining fields become light. this is nothing new. its the same principle behind how antennas work. a field is created which then tries to collapse but because it lags behind the current it has nowhere to go and so becomes light.

 

[malawi_glenn]

in the first post I've described a conceptual experiment were detectors are not needed, for sure.
But, conceptual or not, is a physical question, and what I stress, again, is the unexpected result that at annihilation of pairs P1 and pairs P2 they MUST have different content (energy).
I understand that in particle physics, usually disregards to the propagated fields. After all you are 'only' talking about 'particles', not the outside ordinary electro/ /gravitationaly emited fields. In the Feynman diagrams they are ommited.

I'm prepared to discuss the experiment as stated above,
and, as the experiment sugests ,even contrary to our expectations, we cannot say as you did '..it is more symmetric to assume that all neutrons have same rest mass'.

if you are a student, try to check with your teachers, but keep in mind that is extremelly difficult for a theacher to assume that it has no answer.
I found no answer in the theory.
Everyone is assuming all particles of type P are just equal.

In the beginning of experiment (time T0) pair P1 = pair P2 and by the moment of annihilation pair P1 NOT= pair P2.

You call it anomaly/paradox, but I know that it is not so.

No I didn't call that an anomaly/paradox, I asked why you think it is?

Now let's turn to your fictional experiment, what is causing the particles to annihilate just like that? Is that mechanism needed to be added ad hoc? How would you prepare your experiment?

One does not detect particles with antennas in particle physics experiments :)

 

[heldervelez]

the remaining fields become light. this is nothing new. its the same principle behind how antennas work. a field is created which then tries to collapse but because it lags behind the current it has nowhere to go and so becomes light.

I recommend 'back to basics' elecrostactic
http://en.wikipedia.org/wiki/Electrostatics#The_electric_field
we hava a charge/mass, we have a stationary electromagnetic/gravitational field.
as there is now way of instanct action at distance the fields will occupy the space at c speed,
test particles at different distances will notice the field at different times.
the electrons set the field, that is spreading in space, and they are not radiating a single photon.
in the experiment the remaining fiels surely doesn't become light (photons), they simply continue propagating.
far way from the preexisting source, now vanished, relalivity teaches that the source is still 'visible'.
we don't need to invoke antennas, test particle is enough.

 

[heldervelez]

No I didn't call that an anomaly/paradox, I asked why you think it is?

Now let's turn to your fictional experiment, what is causing the particles to annihilate just like that? Is that mechanism needed to be added ad hoc? How would you prepare your experiment?

One does not detect particles with antennas in particle physics experiments :)

as in the first post:
two photons <-> electron/positron pair, and equal energy on start of both experiments

on both experiments:
creation ......., radiate fields...,... annihilation
two photons -> electron/positron pair ,.....,-> two photons
by theory the energy of the 2 initial photons is the same as the 2 final photons

as a conceptual experiment, no one needs to prepare that. Theory and imagination are enough. But beeing conceptual it is a physical problem, with physical consequences and meaning.
When I say that for me it is not an anomaly neither paradox I'm referring to the meaning and consequences as already stated:

The quantity 'Space And Field' is dependent on particle antiquity.
And so, if the particles are equal in the beginning they must be different in dead, or 'free lunch' is permitted in physics!

 

[Vanadium 50]

If you are talking about electric fields, you can't have a particle of one charge annihilate without it's antiparticle of equal and opposite charge. That means far away the field is zero, unlike what you have drawn in your first message.

 

[heldervelez]

If you are talking about electric fields, you can't have a particle of one charge annihilate without it's antiparticle of equal and opposite charge. That means far away the field is zero, unlike what you have drawn in your first message.

electron and positron have mass and so gravitational fields uphold, and the problem stands as stated.

I think I understand your difficulties. As particle physics you concentrate in 'particles' ignoring fields, invoking virtual-photons for this, gravitons and gluons for that,...
look around : your PC was invented, designed, computer languages invented, sensors, detectors, actuators, even at LHC it was electronic engineers that have created almost all apparatus.
Before focus have moved to particles it was centered in fields. Electromagnetism is fruitfull from the beggining.
And an electronic engineer as no problem in understand this post as formulated.
You can allways think that spacetime around each particle was modified by gravity and expanding at c speed, during the time each pair was 'alive',
the problem stands as stated ab initio.

 

[malawi_glenn]

i) I thought we was dealing with electrodynamics, not electrostatics.

ii) Then if we can't prepare this experiment, maybe we should not draw so many conclusions regarding your example on the neutron mass etc.

Physics is more than "proofs" and "evidence", its a matter of symmetry and beauty.

Are you maybe referring the the process of virtual particle exhange?
The experiemtn you are reffering to is a photon into a e+e- pair which annihilate to form a photon again? You must specify your experiment, what is beeing annihilated with what etc, otherwise one can rule out your reasoning by argument that particles don't annihilate just like that. So situation is ruled out from symmetry reasons.

 

[Vanadium 50]

If you never intended to talk about electromagnetism, why did you yourself bring it up?

As far as arguing how much smarter electrical engineers are than physicists, I don't think that adds any clarity at all.

 

[heldervelez]

If you never intended to talk about electromagnetism, why did you yourself bring it up?

As far as arguing how much smarter electrical engineers are than physicists, I don't think that adds any clarity at all.

quoted from the initial post :
"The question is about the remaining fields, gravitational and/or electromagnetic."

Electronic engineers simply have a different perspective, they are not smarter, and will understand well this sentence in the original post:

"Let 's' = Space and 'f' = Space With Field
(they are physically different, for sure demonstrated by a test particle )"

Since Einstein, and even before, is known that 'Space' is not equal to 'Space with Field'.

is anything wrong with the validity of this assertion ?

 

[NoTime]

Granpa may not be all that far off.
I'd have to do some research to understand the proposed mechanism though.
Standard particle physics would have neutron decay as proton, electron, and an electron-type antineutrino.

http://www.ns.umich.edu/htdocs/releases/story.php?id=3070

 

[heldervelez]

Granpa may not be all that far off.
... would have neutron decay as proton, electron, and an electron-type antineutrino.
http://www.ns.umich.edu/htdocs/releases/story.php?id=3070

and, this is a new observable, also a photon is detected in the range 15 keV..300keV
and appeared in Nature on 21/Dec/2006.
From NIST, you can access the paper (on Jul/Aug 2005) announcing the preparation of the experiment, and also a syntesis of the results, that they say are alligned with the teoretichal work. They also speeak about a refinement of the experiment but nothing new had appeared to public.
I am curious about that article on Nature, but I don't have access to it (only paying).

 

[malawi_glenn]

electron and positron have mass and so gravitational fields uphold, and the problem stands as stated.

I think I understand your difficulties. As particle physics you concentrate in 'particles' ignoring fields, invoking virtual-photons for this, gravitons and gluons for that,...
look around : your PC was invented, designed, computer languages invented, sensors, detectors, actuators, even at LHC it was electronic engineers that have created almost all apparatus.
Before focus have moved to particles it was centered in fields. Electromagnetism is fruitfull from the beggining.
And an electronic engineer as no problem in understand this post as formulated.
You can allways think that spacetime around each particle was modified by gravity and expanding at c speed, during the time each pair was 'alive',
the problem stands as stated ab initio.

i) Who are discovering and inventing the materials which the electronic engineers use and makes electronic engineering possible? Well.. physicsits?

ii) Now since you are discussing this in particle physics forums, you are dealing with another description of fields then what electronic engineers etc does.

iii) Since you understand your own stated "problem", does this justify your statement that an electronic engineeri has no problem to understand your first post as formulated?

So, let me ask this again:

Are your experiment dealing with the creation of a virtual electron-positron pair from photon, which are again let to annihilate an form a photon?

Which are the feynman diagrams for these processes?

 

[ZapperZ]

and, this is a new observable, also a photon is detected in the range 15 keV..300keV
and appeared in Nature on 21/Dec/2006.
From NIST, you can access the paper (on Jul/Aug 2005) announcing the preparation of the experiment, and also a syntesis of the results, that they say are alligned with the teoretichal work. They also speeak about a refinement of the experiment but nothing new had appeared to public.
I am curious about that article on Nature, but I don't have access to it (only paying).

So what does this have anything to do with what you're proposing here?

There's a couple of problems in consistency if you latch on to this:

1. This is a DIFFERENT type of neutron decay than the regular, more common neutron decay. This is a RADIATIVE neutron decay, which can occur only in free neutrons. So this is quite rare (that's why we haven't detected the light signal before).

2. This channel of decay was predicted by QED a long time ago. Why is this significant? This is because QED (and QFT) deals with QUANTUM fields, not your classical field. Considering that you were chastising physicists for not understanding your proposal because they are too apt to look at such problem using "particles", it would be ironic for you to use this as evidence when it came out of a prediction of looking at fields as a quantum field.

Zz.

 

[heldervelez]

i)
So, let me ask this again:

Are your experiment dealing with the creation of a virtual electron-positron pair from photon, which are again let to annihilate an form a photon?

It is not virtuar pair as you wrote, but REAL pair of particles.
As you surely know, bombarding nucleus with photons with the appropriate energy we get pairs of electron/positron as outcome.

I'm sure that you are not sceptic about particles creation (with mass) and the precursors beeing massless (namely electron/positron) !
the intervenient nuclueus is in the middle but energetic balance with him his neutral.
I'm sure that you are not sceptic about particles annihilation (namely electron/positron) !
Also I'm sure you don't need that I have to pinpoint to you were to find those diagrams !

the question as stated in the beginning is until now uncommented/contradicted/denied by any one, and I have to do other things, than to ping-pong in the outer limits of the proposed experiment.

 

[malawi_glenn]

I didn't wrote, I asked.

So the process you are referring to is photon creating a real e+e- pair, and THAT e+e- are beeing annihilated into photons? One photon comes out, and two photons exits?

Now where does that field comes into play? You are measuring this thing be detecting the photons...

 

[heldervelez]

I agree with you mister ZapperZ:
this radiative decaying of neutron as nothing to do with this question. It was predicted for more than 50 years ago.
But you could have notice that in my reply to mister NOTIME I was only quoting him when he told us 'granpa ... ' and informing about the radiative photon, that it didnt mentioned, ... and also to tell that I would like to see that Nature article.

Restrict to the conceptual experiments in the first post.
Please.

 

[malawi_glenn]

one can simpliy get rid of the ambigous situation which you referring to in your conceptual experiment by detecting particles with other means to establish their physical properties.

 

[heldervelez]

As malawi_glenn already pointed out, your question appears similar to the question of "Will the gravitational force experienced by Earth cease to exist at the same instant as the sun disappears".
Since you didn't address the analogy, I'm going to guess that you don't understand that this is an actual question with an undefined answer.
The answers you might get will involve either spacetime geometry response (in GR) or virtual photon/graviton exchange (in a QFT).
This is one (if not the major) underlying reason that there is no unified field theory.
Neither idea would seem to support a need for mass variance between particles of the same type.

I'm sorry because I miss this comment in due time and it deserves a clarification.
Only recenly I've found a post, about the question thay you mentioned "Will the gravity..." (*) and noticed that the question become inconclusive solely on basis that the experiment "Sun disappears" is unphysical. This argument cannot be stated about a pair positron+electron annihilation.
To me, and I think it has a large consensus, it has a defined answer: Gravity speed is 'c', (at most).
It cannot happen 'the field collapses instantly' in any sense.
If it is not like this, we will see 'instant action at distance', which is an attribute of of a 'magic world' or of God. Can you imagine any physical law that survives the 'instant action at distance' property ?
Before Galileu everyone with good common-sense, including all academics, assumed as true that all the universe rotates around the Earth in 24 hours. Can you imagine the potentiality of 'instant action at distance' ?
(*) https://www.physicsforums.com/showthread.php?t=99949&highlight=sun+disappears&page=2

 

[heldervelez]

The OP experiment is not addressed by actual theory. By the time of GR development it was thought that matter did existed since ever and no one imagined that matter could vanish into photons.
The problem was never formulated and of course it was never answered in the actual knowledge.
The challenge remains: An answer is needed.

 

[Gokul43201]

To the OP: You haven't exactly asked a question. What is your question? You seem to be implying that your thought experiment demonstrates a violation of some conservation law. Which one? Please be clear and explicit.

 

[malawi_glenn]

The OP experiment is not addressed by actual theory. By the time of GR development it was thought that matter did existed since ever and no one imagined that matter could vanish into photons.
The problem was never formulated and of course it was never answered in the actual knowledge.
The challenge remains: An answer is needed.

Gravity is not related to rest-mass but to the stress-energy tensor, photons feel gravity. The particle which is annihilating on your 'experiment' does so after interaction with its antiparticle and thus create photons. Energy is conserved, no discontinuity in gravitation field.

So there is no challenge remaining

 

[heldervelez]

To the OP: You haven't exactly asked a question. What is your question? You seem to be implying that your thought experiment demonstrates a violation of some conservation law. Which one? Please be clear and explicit.

http://en.wikipedia.org/wiki/Electron-positron_annihilation" are in complete energetic balance (*) .
Therefore, in each experiment, we start and end with 2 photons whith equal energy.

(*) quote...
Matter creation is the process inverse to particle annihilation. It is the conversion of massless particles into one or more massive particles. This process is the time reversal of annihilation.
...
matter creation is allowed by momentum conservation law
...
end-quote

At the beginning and at the end the energy in photons are perfectly equal in both experiments.
By theory, also in both experiments, the energy on matter-antimatter pair particles (electron-positron pair, or neutron-antineutron,...) is also equal.


Comparing the experiments, we can stop talking about the quantities that are equal on both (photons and matter-antimatter particle pair).

The experiments (initial products and final outcomes) can be compared
( 2 photons) -> (pair+Field1) -> ( 2 photons) -- total time of exper. 1 let's say 1 time unit.
( 2 photons) -> (pair+Field2) -> ( 2 photons) -- total time of exper. 2 let's say 2 time unit.

taking off what is equal we can write :

Field1 is equal to Field2
or
Field1 is different from Field2

(Field1 and Field2 are abreviations of Space+Field on experiment 1 and 2)

Do we agree until now?

-----------------------------

next post I will say that the correct assertion is
Field1 is different from Field2

implying that energy content of particle pair at end of experiment 1 MUST be different of energy content of particle pair at end of experiment 2. This is an unexpected result.

 

[malawi_glenn]

What is the field, gravitational field or electromagnetic field?

 

[heldervelez]

Electrons and positrons have mass and generate gravitational effects. Tiny effects that I think not measurable by us.

To make the experiment simpler, and more clear we can choose the gravitational field.
It is not canceled and it has long range effects.

The observers are located in the center of mass where the two photons collided and the pair was produced, in both experiments. And they can measure the effects.

Looking around from that positions the worlds are equal.

 

[malawi_glenn]

If we consider gravity, there is no problem at all since gravity is assigned to energy, not mass as indicated in post #33.

 

[heldervelez]

But in post #34 we get rid of photons because the net effect in both experiments are equal.
...
But now I see your point and I have to prepare myself.
I see a 'wasp nest' now.
I do know that photons 'feels' gravity as you said, in the sense that they will follow the geodesic that curved-space imposes by gravitation. Also that 'gravitation gravitates' as 'the field has energy' (as I also say).
But I do not know if photons contribute to gravity field.
I did found a lot of threads on this forum about the subject, and a lot of discussion and no consensus.

By http://www.bartleby.com/173/" I see that the equivalence of inertial mass with gravitational mass is the basis of GR formulation. On that Einstein paper I saw no reference on photons as possible gravity sources.

When I wrote the OP I was not considering that photons could have inertial mass (neither gravitational mass). And I see now, that you consider the opposite.
By experimentation it seems almost impossible because we can not assemble zillions of photons to measure. (the 'almost' word is there just in case). But this is not the point in question.

This week-end I will study the arguments against my position.

 

[malawi_glenn]

Consider a container filled with photons, the container will have mass. That is the "experiment"

 

[Vanadium 50]

If photons fall to Earth (as has been measured) but do not themselves generate a gravitational field, momentum conservation is violated.

 

[heldervelez]

Consider a container filled with photons, the container will have mass. That is the "experiment"

Have energy for sure (water: compare water vapour with ice, they are the same but not alike) and a mass equivalent (another way of expression of energy).

 

[heldervelez]

I was wrong when I wrote that photons have not inertial mass. Yes they have inertial mass (i.e. bend on accelerated frames) and have gravitational mass (i.e. bend on gravitational fields).
About beeing or not responsables themselves as sources of gravity field is more critical.
I need more readings (In GR it is said yes, I found it on the 1916 papper), but do we have an experimental confirmation? It could be done, to prove or disprove, the assertion that light are sources of gravity (independently of GR saying so).
With extreme power lasers of today and try to bend the trajectories of UCN (ultra cold neutrons) beam.
Does anyone know of an experiment that proves that light is source of gravitational effects ?

May be old fashion but I represent a 'field' with some sentences.
Field means a need for the existence of a gradient.
Without gradient there is no 'field'.
Field means also: the ability of action on a distance, timely of course, not instant action!
Without fields the universe would be static.
With instant action at distance, the universe would be magical, without laws. No cause, no consequence, no previous nor next events.

Suppose all space of universe filled with photons.
Then the distribution of energy thru space has to be considered uniform, and the space has plenty of energy. Is this gravitational energy ? To me is energy, but not 'field'.

May be we wish to call it gravitational energy. But to me is enough call it energy.

Suppose that below is a representation of an infinite world of equal particles at rest and with a isotropic and constant distribution of mass.
Each particle remains at rest, and keeps at rest, and see no 'field'.

...
...
... ...........
... ...........
... ...........
... ...........
... ...........
... ...........
... ...........
... ...........
... ...........
... ...........
...
...

I see energy, (mass) (or gravitational energy ?) but I do not see field.

The same for a universe of photons.
Photons are not 'localized' like we 'think' about 'particles'.
What is the configuration of the gravitational field associated to a photon ?
(With a definite mass we remember the rubber sheet association)
The photon also as 'c' speed. How do field 'spread' in the space around 'what?'.
Having zero rest mass and traveling at 'c' speed, makes photons the limiting case for all other positive finite masses, not one of them. How gravitons (*) could interact with a wavefront moving a 'c' ?

(*) I do not like the gravitons idea. It has to have some other, more appealling ways of explaining gravitational interactions. Why the need of gravitons if it is the space that is 'bended' and the natural path for anybody is to follow the geodesic? The space itself makes the road from where there is no chance to deviate.

Later I will continue the OP experiment. This post was to express some difficulties with the notion of field (may be I'm old fashion) , and that, it is not clear why and how light contributes to gravity.

"Usually photons are not confined in a container, aka mirrored box"

I will try to continue the thread even if we disagree with the above questions.

 

[malawi_glenn]

heldervelez, we can help you find a modern textbook on GR - in 1916 there was not so many proofs for GR, but now we are 90 years later! GR is one of the best proven theories in physics, Einstein was not elected "person of the century" by Times for nothing.

So, yes, you are a bit old fashioned. You should study modern GR (Einsteins theory + applications + observational / experimental verifications). And you should also study modern Quantum Field theory.

Then you can start to study Grand Unification theories and Theories of Everything -> the reason for 'why we want' gravitons is that GR is a NON QUANTUM theory and everything else is Quantum theory (strong force, weak force and electromagnetism). So one would like to have a quantum theory of Gravity as well.
Then we have shown that the weak force and electromagnetism are really ONE force, but this is only manifested at very high energies -> Electroweak unification. So one would like to unify all forces into one. String theory is the most studied candidate for this.

So this was some introduction to what contemporary physics is.

 

[heldervelez]

https://www.physicsforums.com/showpost.php?p=1899079&postcount=1" points to a document were are done all the calculations that prove my point.

This kind of problem is not addressed in textbooks, and we have to do the homework.

The textbooks AFAIK only addresses the fields already settled in space for ages, as if matter had an infinite age and as if the field had an infinite speed of propagation. We may consider theese points as details, not written in the equations and make all the difference.

The formalism involved is nothing more than plain electromagnetism.

Tha calculations are 'facts'/evidence. The author's conclusions/paradoxes I do not share. A priori they are out of the scope of the discussion.

I made my case(*) if the calculations are not proved wrong.

Calculate the energy that fills two infinitesimal shells, centered at the mass/charge point, traversed at times t1 and t1+dt and t2 and t2+dt by integrating in those volumes the energy density (electrostatic, magnetic, or gravitational field) of a propagating field, at 'c' speed.
The distance to the center is, say, x1 and x1+c.dt for the first shell and x2 and x2+c.dt for the second shell.

Resulting :
E1=Energy within the 1st shell = Konstant * c*dt /((x1 + c*dt) * x1)
E2=Energy within the 2nd shell = Konstant * c*dt /((x1 + Dx +c*dt) *( x1 +Dx) )
resulting »» 0 < E1 < E2

beeing Dx = x2 -x1 (distance between both shells)
Konstant = Q^2/(8*pi*eps0) beeing Q the charge
the Konstant will have other value for the gravitational case.

-----------------------
Turtur, Claus W. (2007).
Two Paradoxes of the Existence of electric Charge.
arXiv:physics/0710.3253 v1

Abstract
A thought experiment is considered in which somebody observes an electrical charge, moving with constant speed relatively to a given frame of reference, in which the observer is in rest. Let us further assume that no electric fields and no magnetic fields interact with this moving charge, so that there is no force acting on the charge. Consequently it keeps constant speed.
But the moving charge itself produces a magnetic field within the reference frame. Because the moving charge does not alter its speed and thereby its energy, it can not emanate any power. But the generated magnetic field contains energy, and we can calculate the power being emanated from the moving charge, which we find to be not constant as a function of time. The existence of this energy and the alteration of the power is a first paradoxon of the magnetic field.
If we follow the trace of a specified element of volume containing field energy, a further calculation proves, that this contents of energy decreases during time. This unexplained loss of energy as a consequence of the mere propagation in space is a second paradoxon of the magnetic field.

by
Prof. Dr. Claus W. Turtur
University of Applied Sciences Braunschweig-Wolfenbüttel

--------------------
(*) I have made a mistake when I invoked the energy conservation of the problem. As calculations showed I was wrong.

My sincere tanks to Mr malawi for the fairness,
and with a bit of irony , also the solicitude in pointing me 'a modern textbook on GR'. I do know that GR and SR are valid, but the details..., probably are not written on any textbook.