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#7097 06/02/06 06:04 PM
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What is the mass of photon ?
Its true that photon hasn't any mass?
Tks.


mfm
.
#7098 06/02/06 07:02 PM
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It must be true. If it had mass it would mean that it had inertia; which, in turn, means that there must be an inertial reference frame within which the photon will be stationary. This is not possible in terms of Einsten's theory of special relativity. I put my bet on Einstein.

#7099 06/02/06 08:54 PM
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Johnny Boy defending the conventional scientific view? Wow, I'm impressed!


As shown in this article the experimental limits on the photon mass aren't as strong as previously thought.

#7100 06/02/06 09:54 PM
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Quote:
Originally posted by Count Iblis II:
Johnny Boy defending the conventional scientific view? Wow, I'm impressed!


As shown in this article the experimental limits on the photon mass aren't as strong as previously thought.
Thank you for the compliment. In my mind mass responds to inertia and also energy. So it has to be the potential energy of a stationary particle relative to its proper inertial reference frame. When solving the Schroedinger equation for a free electron it is assumed in textbooks that it has no potential energy. Delocalised waves are then generated that have to stretch over the whole universe requiring a special stationary inertial reference frame: this violates Einstein. A stationary free electron has mass-energy because its potential energy is that of the ground-state of a harmonic oscillator; i.e it experiences a stable minimum potential energy. Thus if I am correct that mass means stable equilibrium relative to the proper inertial reference frame of a particle, then a photon cannot have mass.

#7101 06/03/06 08:28 AM
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Very thanks, i undestand almost all your says, althought i dont understand what this means. "
its potential energy is that of the ground-state of a harmonic oscillator "

Its possible to explain a little bit more to an amateur ?

And another question, if you say the mass photon dont exist "It must be true, the, " is there another scientifics or theorys that maintain its opposite, that the photon mass exists, or isn't = 0 ?


mfm
#7102 06/03/06 12:27 PM
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manfermef, in his second posting, Johnny Boy is again playing his usual role in this forum, i.e. to write about his personal theories.

Joohnny Boy somehow deduced that the photon must be massless, but he didn't use any of the photon's properties in his reasoning. So, his argument must be wrong, because you could replace ''photon'' by any other particle in his argument and then you would have to conclude that all particles are massless.

The Z-boson is a particle that is very similar to the photon. But it is very massive. Special relativity just states that theories must be symmetrical under so-called Lorentz transformation. A massive photon would not violate special relativity at all.

#7103 06/03/06 04:02 PM
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Well explained Count!!

Then I sum up that isnt sure the photon is whithout any mass.
At least that its not demonstrate by science.

Its all ok?


mfm
#7104 06/03/06 05:23 PM
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Quote:
Originally posted by Count Iblis II:
manfermef, in his second posting, Johnny Boy is again playing his usual role in this forum, i.e. to write about his personal theories.

Joohnny Boy somehow deduced that the photon must be massless, but he didn't use any of the photon's properties in his reasoning. So, his argument must be wrong, because you could replace ''photon'' by any other particle in his argument and then you would have to conclude that all particles are massless.
I am afraid that Count Iblis II is displaying his ignorance of Galileo's statement of relativity that finally led to Newton's first law. I still think that one should first truly understand Newton's mechanics before spouting nonsense about the physics that came after it. Any "particle" can have two types of energy: kinetic and potential. Without kinetic energy it can only have potential energy. Mass is energy and within the inertial reference frame that a particle with mass is stationary its "rest mass" must represent its lowest energy state. But it is not kinetic energy because the particle is stationary within its proper inertial reference frame. Even Einstein's special theory of relativity tells you that the rest mass is NOT kinetic energy. So it must be potential energy which manifests when the particle is at rest within its inertial reference frame. A photon can never be at rest within any inertial reference frame. So it cannot have potential energy which can be ascribed to mass. What is illogical about this argument Count Iblis II. Or do you not believe that the rest mass is energy? Where do my "personal theories" come in? The argument is based on physics that has been accepted as correct (at low speeds) for more than 300 years, as well as Einstein's special theory of relativity which is now more than 100 years old!!!


Quote:
Originally posted by Count Iblis II:
The Z-boson is a particle that is very similar to the photon. But it is very massive. Special relativity just states that theories must be symmetrical under so-called Lorentz transformation. A massive photon would not violate special relativity at all.
Yes, but in contrast to a photon the Z-boson has a rest mass and can thus be stationary relative to its proper reference frame; or what does the term "rest mass" tels you Count Iblis II? It seems to me that YOU are rather having you own theories; which are at variance with Newton's laws and Einstein's relativity theory!

#7105 06/03/06 05:34 PM
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Quote:
Originally posted by manfermef:
Very thanks, i undestand almost all your says, althought i dont understand what this means. "
its potential energy is that of the ground-state of a harmonic oscillator "

Its possible to explain a little bit more to an amateur ?

If you go back to the classical literature on Newton's mechanics, you will realise why the term "inertia" has come into use. This is unfortunately not always explained well in modern books on classical mechanics. It means that a body with mass will resist being moved from rest. This means that the body at rest MUST be in stable equilibrium. Generally in physics most situations where a body is in stable equilibrium, requires a restoring force to come into action when you try to move the body; i.e. the body or particle experiences a potential well; usually parabolic; within which it performs harmonic movement when disturbed. This is why I expect that the wave intensity, which is the solitary electron, will be a three-dimensional zero-point function with energy equal to the rest mass of the electron.

#7106 06/03/06 08:26 PM
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Quote:
Originally posted by manfermef:
Well explained Count!!

Then I sum up that isnt sure the photon is whithout any mass.
At least that its not demonstrate by science.

Its all ok?
That's right, but that there are good theoretical reasons to believe that the photon mass is exactly zero. These theoretical reasons are not fullproof and ultimately you have to rely on experimental results. And experiments can only give you an upper bound on the photon mass.

According to the so-called Standard Model of paticle physics all particles get their mass due to interactions with the Higgs particle. This theory predicts that the photon should be exactly massless, while some other particles like the Z I mentioned are massive. It is possible, however, that new particles like the Higgs exists which do give the photon a tiny mass.

#7107 06/03/06 08:33 PM
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I Thank your efforts to explain something really difficult to understand, Johnny.

Then really the photon cant stop to moving ?

Are you saying that photon cant stop ? when you says that

"A photon can never be at rest within any inertial reference frame."

Then my finally question is: the massless photon dont contradict the Einstein's E=mc2 , because E=mc2 is equal 0 if m=0 ?


mfm
#7108 06/03/06 08:44 PM
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Quote:
Originally posted by Johnny Boy:
I am afraid that Count Iblis II is displaying his ignorance of Galileo's statement of relativity that finally led to Newton's first law. I still think that one should first truly understand Newton's mechanics before spouting nonsense about the physics that came after it. Any "particle" can have two types of energy: kinetic and potential. Without kinetic energy it can only have potential energy. Mass is energy and within the inertial reference frame that a particle with mass is stationary its "rest mass" must represent its lowest energy state. But it is not kinetic energy because the particle is stationary within its proper inertial reference frame. Even Einstein's special theory of relativity tells you that the rest mass is NOT kinetic energy. So it must be potential energy which manifests when the particle is at rest within its inertial reference frame. A photon can never be at rest within any inertial reference frame. So it cannot have potential energy which can be ascribed to mass. What is illogical about this argument Count Iblis II. Or do you not believe that the rest mass is energy? Where do my "personal theories" come in? The argument is based on physics that has been accepted as correct (at low speeds) for more than 300 years, as well as Einstein's special theory of relativity which is now more than 100 years old!!!

Johnny Boy! The question that was asked was whether it is theoretically possible for the photon to have a nonzero mass, given all what we know today (i.e. all the experimentally established facts). By stating that
Quote:
A photon can never be at rest within any inertial reference frame
you are already assuming that the photon is massless. The question is if we can drop this assumption.

If the photon had a tiny mass, you would have to rewrite relativity textbooks because most books talk about the speed of light being an invariant. However, the theory itself would still be the exactly the same. I.e. you would have an invariant maximum speed at which a massless particle would travel instead of ''lightspeed''.

Quote:
Originally posted by Johnny Boy:

Quote:
Originally posted by Count Iblis II:
The Z-boson is a particle that is very similar to the photon. But it is very massive. Special relativity just states that theories must be symmetrical under so-called Lorentz transformation. A massive photon would not violate special relativity at all.
Yes, but in contrast to a photon the Z-boson has a rest mass and can thus be stationary relative to its proper reference frame; or what does the term "rest mass" tels you Count Iblis II? It seems to me that YOU are rather having you own theories; which are at variance with Newton's laws and Einstein's relativity theory!
That's right. But the question was if the photon could in theory have a nonzero rest mass. The answer is that while the best theories we have predict that the photon is exactly massless, it is not theoretically impossible for the photon to have a very very small mass.

#7109 06/03/06 11:55 PM
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theoritically speaking, if a photon is never at rest, it cant have rest mass. one theory that i heard while training in the use of repair of lasers, was that photons are never at rest. they are either moving on their own or they are captured by the electrons of an atom thereby raising the electons energy. the release of that energy results in the photon moving at light speed because it was moving at lightspeed inside the energy shell of the electron.

photons are either particle (with mass) that behave like energy waves or energy waves that act like particle. as yet no one has been able to determine the difference between energy wave and particle enough to describe which it is.


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#7110 06/04/06 12:53 AM
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Topic: Mass of Photon.

I am a neophite here but I can appreciate the ideas that are being considered. My preference is to reduce a concept to its essentials if I can so we can look upon a photon blasting off from the Sun out into space. Either it was not a photon at rest on the Sun or it was created on the spot by the fusion activity of the Sun. When created we can consider that it has no Mass so that is easy. If we contemplate the photon was there to begin with then we must weigh the prospect that the photon was at rest and may possibly have had an original rest status consistent with inherent Mass. When the blast off occurs we either have a conversion of Mass into energy or a uniquely energized particle off into space which may have converted its Mass, if any, into energy.

This new Massless photon will now travel millions of light years expanding constantly to full the ever expanding volumn of space so some stranger far away will see the light.

Question: If the photon has no Mass and if Mass is the source of energy how does the photon manage to travel so many light years away and stiil have substance to be seen by others?

Is the picture the photon carries in its form an indication of substance or of something special?

You know I will be unequiped to challenge any answer you provide.

jjw

#7111 06/04/06 09:42 AM
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Quote:
Originally posted by Count Iblis II:
Quote:
Originally posted by manfermef:
Well explained Count!!

Then I sum up that isnt sure the photon is whithout any mass.
At least that its not demonstrate by science.

Its all ok?
That's right, but that there are good theoretical reasons to believe that the photon mass is exactly zero. These theoretical reasons are not fullproof and ultimately you have to rely on experimental results. And experiments can only give you an upper bound on the photon mass.

According to the so-called Standard Model of paticle physics all particles get their mass due to interactions with the Higgs particle. This theory predicts that the photon should be exactly massless, while some other particles like the Z I mentioned are massive. It is possible, however, that new particles like the Higgs exists which do give the photon a tiny mass.
I am unhappy when people use the sdtandard model as if it has been experimentally verified to be correct. The standard model requires renormalisation and is based on guage symmetries. If it is correct, which I will acept once it is experimentally proved to be correct, then it is still nothing more than an elaborate peeriodic table. Just like Mendeleev's periodic table has been a great breakthrough, it was derived on symmetries without knowing the real physics behind it Bohr finally explained the real physics.

One should note that Count Iblis II bandies around the Higgs boson as if it is an experimental fact: IT IS NOT!. I find his arguments very irresponsible.

The fact is that a particle with mass has a "rest mass" and this logically implies that it can be statiionary relative to its proper inertial reference frame. According to Einstein, a photon can NEVER be stationary. If Einstein is correct than it is impossibnle for a photon to have mass. If it is Einstein's special theory of relativity has to be abandoned.

#7112 06/04/06 09:48 AM
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Quote:
Originally posted by manfermef:
I Thank your efforts to explain something really difficult to understand, Johnny.

Then really the photon cant stop to moving ?

Are you saying that photon cant stop ? when you says that

"A photon can never be at rest within any inertial reference frame."

Then my finally question is: the massless photon dont contradict the Einstein's E=mc2 , because E=mc2 is equal 0 if m=0 ?
E=mc2 does not apply to a photon because a photon do not have potential rest energy; it only has kinetic energy given by Planck's relationship.
If it should be found experimentally that a photon has mass, it would mean that other particles with mass will be able to travel at light speed. It would hange physics completely. Contrary to Count Iblis II I am open to new ideas, but I find it highly unlikely that a photon has any mass.

#7113 06/04/06 10:02 AM
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Quote:
Originally posted by Count Iblis II:
Quote:
Johnny Boy! The question that was asked was whether it is theoretically possible for the photon to have a nonzero mass, given all what we know today (i.e. all the experimentally established facts). By stating that [QUOTE] A photon can never be at rest within any inertial reference frame
you are already assuming that the photon is massless. The question is if we can drop this assumption.

The answer is that while the best theories we have predict that the photon is exactly massless, it is not theoretically impossible for the photon to have a very very small mass.
OK that is another aspect of the question which, I agree, I have not been addressing in my analysis. As I said, I am always open to new ideas; but they are difficult to swallow at this stage of the game when they are based on Higgs bosons; maybe in a couple of years the Hadron Collider will provide an answer. After all, theoretically anything is possible, but it takes experiment to decide which theoretical description really tallies with experiment. You can even have a mathematical description that tallies with experiment because it is mathematically consistent; but it does not really describe the underlying physics; for example, you can repoduce violin music in terms of digital code, but this does not imply that violin nopte are physically digital code. You can assume, like Feynman, that an electron can do "anything" and then add enough of these "anythings" to get a description which seems to represent the electron. This, however, does not prove to me that an electron can do "anything".

#7114 06/04/06 10:12 AM
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Quote:
Originally posted by dehammer:
theoritically speaking, if a photon is never at rest, it cant have rest mass. one theory that i heard while training in the use of repair of lasers, was that photons are never at rest. they are either moving on their own or they are captured by the electrons of an atom thereby raising the electons energy. the release of that energy results in the photon moving at light speed because it was moving at lightspeed inside the energy shell of the electron.
I do not believe that a photon moves at light speed "inside the energy shell of the electron". What happens, in my opinion, is that the photon and "electron orbital" (which I believe is the electron") entangles to form a higher energy electron orbital. For the electron to form a higher-energy staionary electron orbital its mass has to increase; thus the photon energy adds to increase the mass-energy of the bound electron.

Similarly when analysing the photo-electric effect: The photon entangles with the electron wave to in this way increase its mass. If the mass becomes more than the rest mass of the electron; the additional mass acts as kinetic energy which allows the electron to speed away. Thus one do not need to model the photo-electric effect as a collision between two "particles".

Quote:
Originally posted by dehammer:
photons are either particle (with mass) that behave like energy waves or energy waves that act like particle. as yet no one has been able to determine the difference between energy wave and particle enough to describe which it is.
As you see from my alternative analysis of the photo-electric effect, the so-called particle collisions are an illusion; one can explain everything interms of waves that superpose or entangle.

#7115 06/04/06 10:39 AM
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Quote:
Originally posted by jjw004:
Topic: Mass of Photon.

I am a neophite here but I can appreciate the ideas that are being considered. My preference is to reduce a concept to its essentials if I can so we can look upon a photon blasting off from the Sun out into space. Either it was not a photon at rest on the Sun or it was created on the spot by the fusion activity of the Sun. When created we can consider that it has no Mass so that is easy. If we contemplate the photon was there to begin with then we must weigh the prospect that the photon was at rest and may possibly have had an original rest status consistent with inherent Mass. When the blast off occurs we either have a conversion of Mass into energy or a uniquely energized particle off into space which may have converted its Mass, if any, into energy.
Very nice question! Most of the light coming from the sun is "blackbody radiation". Although you can model blackbody radiation as photons following Bose-Einstein statistics; it can also be modelled as standing waves following Maxwell-Boltzmann statistics. I believe the latter is the correct picture before a photon is ejected from the sun on its journey. Why? Because the energy-level density of black-body radiation can only be derived from the boundary conditions applicable to standing waves. Photons as localised entities cannot be used to calculate the energy-level density. Thus one has to conclude that the waves are "stationary" waves; however, these waves are not "time-independent", like a stationary wave representing a particle with mass. They are rather similar to standing waves on a violin string. The standing wave is formed because you have two waves moving in opposite directions (each with speed c) because you get reflection at the boundaries. This means that an escaping light wave, most probably, "collapses" to form a more localised entity when it leaves the sun. At that stage this entity need not be completely localised to be what we call a photon; it only needs to "collapse" into the latter state when it is observed by a detector like your eye.

Quote:
Originally posted by jjw004:
Topic: Mass of Photon.
Question: If the photon has no Mass and if Mass is the source of energy how does the photon manage to travel so many light years away and stiil have substance to be seen by others?
Light has energy. As agreed above, even by Count Iblis II, mass means that a "particle" can be stationary relative to an inertial reference frame. As far as we know, this is not possible for light. This does not imply that light has no energy; it must have kinetic energy because it is always moving with a speed c

Quote:
Originally posted by jjw004:
Topic: Mass of Photon.
Is the picture the photon carries in its form an indication of substance or of something special?
jjw
I do not understand what you are trying to ask here?

#7116 06/04/06 01:12 PM
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Quote:
Originally posted by Johnny Boy:
[QUOTE]I do not believe that a photon moves at light speed "inside the energy shell of the electron". What happens, in my opinion, is that the photon and "electron orbital" (which I believe is the electron") entangles to form a higher energy electron orbital. For the electron to form a higher-energy staionary electron orbital its mass has to increase; thus the photon energy adds to increase the mass-energy of the bound electron.

Similarly when analysing the photo-electric effect: The photon entangles with the electron wave to in this way increase its mass. If the mass becomes more than the rest mass of the electron; the additional mass acts as kinetic energy which allows the electron to speed away. Thus one do not need to model the photo-electric effect as a collision between two "particles".

As you see from my alternative analysis of the photo-electric effect, the so-called particle collisions are an illusion; one can explain everything interms of waves that superpose or entangle.
that is one theory, not totally new, but different that any ive seen. still neither this or the one i mentioned has ever been proven. nor has any of the other theories as to exactly what a photon is. One day, someone will come up with conclusive proof, and the arguement will end. at that point we (or our decendants) will know if it has mass or not. until then no one will know exactly. that is why i alway add that line about it being one or the other (watch it be neither) when ever i discuss laser or light.


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