Mass of Photon: Is 0 Rest Mass Possible?

In summary: So, when you say that a photon has no rest mass, what you are really saying is that it has zero relativistic mass. But that's not really very helpful, is it?
  • #36
Meir Achuz said:
ZZ: I don't know you, but why waste your time on this?
People never get what they'll never get.

I was bored out of my mind in our Control Room trying to get 60 nC of electrons to pass through a tube the size of a drinking straw!

:)

Zz.
 
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  • #37
robphy said:
By the way, in your manuscript,
before drawing your conclusion on Einstein's comment that "It is not good to introduce the mass [expression for relativistic mass]...", it might be worth checking whether there were any changes in text between the last editions of "The Meaning of Relativity".
That was the first thing that I did. I had an expert GR historian (Dr. John Stachel, Boston Univ., former editor of the Einstein papers project) confirm it for me just to double check. I figured that'd be the first objection someone should bhring up. But that's not the only place. He mentioned the mass of light in the book he wrote with Infeld "The Evolution of Physics."

I'm not saying any of these things necessarily happened... but I think your conclusion needs more justification.
Which ones? All of them? :cry:

Pete
 
  • #38
pmb_phy said:
That was the first thing that I did. I had an expert GR historian (Dr. John Stachel, Boston Univ., former editor of the Einstein papers project) confirm it for me just to double check. I figured that'd be the first objection someone should bhring up. But that's not the only place. He mentioned the mass of light in the book he wrote with Infeld "The Evolution of Physics."

:approve: Actually, he was one of the folks I had in mind who could check this. (Is he still at Boston U.?) From what I can tell, he's a nice guy with lots of interesting insights. Too bad I only get a brief chance to chat with him at busy conferences... and at these opportunities I don't get a chance to ask my real questions.


pmb_phy said:
Which ones? All of them? :cry:

Pete

I actually didn't read your entire manuscript (although I think I read a draft a while back)... In my last post, I was specifically referring to your conclusion suggesting that Einstein's comment in the letter to Barnett (often used by advocates for emphasizing proper/rest-mass and de-emphasizing relativistic/inertial-mass ) is somehow to be dismissed regarding this issue because it isn't followed up in later publications.

Have you submitted your manuscript for publication?


You might be interested in

http://arxiv.org/abs/physics/0504110
On the Abuse and Use of Relativistic Mass
Authors: Gary Oas

http://arxiv.org/abs/physics/0504111
On the Use of Relativistic Mass in Various Published Works
Authors: Gary Oas
 
  • #39
robphy said:
:approve: Actually, he was one of the folks I had in mind who could check this. (Is he still at Boston U.?)
Yep. Still at BU.
From what I can tell, he's a nice guy with lots of interesting insights.
He's a very nice guy. He's helped me out on many occasions. Sometimes we just talk about life. There was a flamer who was obssesed with me at sci.physics.relativity and would post all sorts of lies and try to use the fact that I had Leukemia to tick me off. When he did that I said every four letter word I knew to him, but only when he did the Leukemia thing - too disgusting to do on a physics discussion board. In the end someone e-mailed Stachel telling him I'm a bad guy and I swear at people. I told him the whole story. It turns out that his mom passed away from Leukemia so we had some common ground. He's a great guy and fun to talk to.
I actually didn't read your entire manuscript (although I think I read a draft a while back)... In my last post, I was specifically referring to your conclusion suggesting that Einstein's comment in the letter to Barnett (often used by advocates for emphasizing proper/rest-mass and de-emphasizing relativistic/inertial-mass ) is somehow to be dismissed regarding this issue because it isn't followed up in later publications.
That was never my intention. My intention was that he used relativistic mass but he didn't use it in the form [itex]M = \gamma m_0 [/itex] but he used in in other forms like "Light has mass" and in Mach's principle where he held that mass piled up near a massive particle will change the (relativistic) mass of the particle. He did emphasize that it was moving slowly but the "slow moving particle" did not have the rest mass = proper mass and that was his piont there. I made the point that proper mass does not always equal rest mass but I guess some people missed it the way I wrote it.
Have you submitted your manuscript for publication?
Yes. There is a standing rule at AJP - "Try as best you can to reject relativity articles". A friend of mine has reviewed articles there for a very long time and the editor would tell him that. I figured I'd try anyway because I think its a good article. The reviewer didn't think so. E.g. he said that nobody he knows thinks light has mass. My friend told me that the reviewer didn't know what he was talking about. My friend thought the artilce was very good. Perhaps you'd heard of him - Robert W. Brehme (as in Brehme diagram)? He wrote a relativity textbook which is awesome. Schutz recommends it (highly?) in his GR text.
You might be interested in

http://arxiv.org/abs/physics/0504110
On the Abuse and Use of Relativistic Mass
Authors: Gary Oas

http://arxiv.org/abs/physics/0504111
On the Use of Relativistic Mass in Various Published Works
Authors: Gary Oas
Thanks. I'll check them out. Much appreciated.

Pete
 
  • #40
robphy said:
:approve: Actually, he was one of the folks I had in mind who could check this. (Is he still at Boston U.?)
Yep. Still at BU.
From what I can tell, he's a nice guy with lots of interesting insights.
He's a very nice guy. He's helped me out on many occasions. Sometimes we just talk about life. There was a flamer who was obssesed with me at sci.physics.relativity and would post all sorts of lies and try to use the fact that I had Leukemia to tick me off. When he did that I said every four letter word I knew to him, but only when he did the Leukemia thing - too disgusting to do on a physics discussion board. In the end someone e-mailed Stachel telling him I'm a bad guy and I swear at people. I told him the whole story. It turns out that his mom passed away from Leukemia so we had some common ground. He's a great guy and fun to talk to.
I actually didn't read your entire manuscript (although I think I read a draft a while back)... In my last post, I was specifically referring to your conclusion suggesting that Einstein's comment in the letter to Barnett (often used by advocates for emphasizing proper/rest-mass and de-emphasizing relativistic/inertial-mass ) is somehow to be dismissed regarding this issue because it isn't followed up in later publications.
That was never my intention. My intention was that he used relativistic mass but he didn't use it in the form [itex]M = \gamma m_0 [/itex] but he used in in other forms like "Light has mass" and in Mach's principle where he held that mass piled up near a massive particle will change the (relativistic) mass of the particle. He did emphasize that it was moving slowly but the "slow moving particle" did not have the rest mass = proper mass and that was his piont there. I made the point that proper mass does not always equal rest mass but I guess some people missed it the way I wrote it.
Have you submitted your manuscript for publication?
Yes. There is a standing rule at AJP - "Try as best you can to reject relativity articles". A friend of mine has reviewed articles there for a very long time and the editor would tell him that. I figured I'd try anyway because I think its a good article. The reviewer didn't think so. E.g. he said that nobody he knows thinks light has mass. My friend told me that the reviewer didn't know what he was talking about. My friend thought the artilce was very good. Perhaps you'd heard of him - Robert W. Brehme (as in Brehme diagram)? He wrote a relativity textbook which is awesome. Schutz recommends it (highly?) in his GR text.
You might be interested in

http://arxiv.org/abs/physics/0504110
On the Abuse and Use of Relativistic Mass
Authors: Gary Oas

http://arxiv.org/abs/physics/0504111
On the Use of Relativistic Mass in Various Published Works
Authors: Gary Oas
Thanks. I'll check them out. Much appreciated.

A friend of mine said he'd sponsor my paper for the physics archive so it will be there soon I hope. Then I'll try another journal for publishing. Any recommendations you might have as to which journal?

Pete
 
  • #41
pmb_phy said:
If that were universally true then the authors of all the textbooks and journal articles listed here

http://www.geocities.com/physics_world/relativistic_mass.htm

would have to be rewritten so as to comply with your assumption. In particular look at all the links to particle accelerator labs listed towards the bottom. Especially this one from CERN

http://humanresources.web.cern.ch/humanresources/external/training/tech/special/AXEL2003/AXEL-2003_L02_24Feb03pm.pdf

Pete

I didn't see anything objectionable in the article. The authors were making it clear that they were talking about relativistic mass.

They did not use "mass", unqualfiied, to mean relativistic mass. Nor did they say that "a photon is not a massless particle", the original statement that I objected to.
 
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  • #42
Would there be any advantage of using inductance instead of mass?

1 - You might be wondering if there is an equivalent of the mass in the electrical domain ... ... There is indeed such an element, and it is called an inductor.
http://othello.mech.northwestern.edu/ea3/book/elec8/Inductors.htm

2 - Mass is merely the self-inductance of an electric field.
http://home.netcom.com/~heensle/phys/book/induct.html
 
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  • #43
pmb_phy said:
Yes. There is a standing rule at AJP - "Try as best you can to reject relativity articles". A friend of mine has reviewed articles there for a very long time and the editor would tell him that. I figured I'd try anyway because I think its a good article. The reviewer didn't think so. E.g. he said that nobody he knows thinks light has mass. My friend told me that the reviewer didn't know what he was talking about. My friend thought the artilce was very good. Perhaps you'd heard of him - Robert W. Brehme (as in Brehme diagram)? He wrote a relativity textbook which is awesome. Schutz recommends it (highly?) in his GR text.

A friend of mine said he'd sponsor my paper for the physics archive so it will be there soon I hope. Then I'll try another journal for publishing. Any recommendations you might have as to which journal?

Pete

I can believe that such a rule exists. My first attempt was turned out a few years ago. My revised and extended version was also recently turned down. I'm convinced that there has been some resistance to "spacetime diagrams". Out of the blue, someone invited me to contribute to a special issue of another journal... so, I submitted it to them as well as put it on the arxiv. I think one strategy to help overcome that hurdle is to mingle among those in physics pedagogy (some of whom may be reviewers)... and try to get them to look at your stuff. So, I've ramped up my AAPT activity.

Yes, I know of (but don't know personally) Brehme. What has become of his diagram? Does he still use and advocate his diagram?

As for another journal, I'm not sure... EJP, maybe?
 
  • #44
pervect said:
I didn't see anything objectionable in the article. The authors were making it clear that they were talking about relativistic mass.
The point was that they never used the qualifier "relativistic" and write "relativistic mass." When they used the term "mass" without a qualifier it always meant "relativistic mass."
They did not use "mass", unqualfiied, to mean relativistic mass.

Page 3 reads
Then the mass of a moving particle is [itex]m = \gamma m_0[/itex].
There is no qualifier here nor elsewhere where relativistic mass is used.
Nor did they say that "a photon is not a massless particle", the original statement that I objected to.
Why would they? I was speaking about nomenclature and that page is about accelerators not photons. Whether a photon has relativistic mass is not a question of debate by those who understand relativity. There are planty of texts to back this up, i.e. any SR text that uses rel-mass states that photons have mass

Pete
 
  • #45
robphy said:
Yes, I know of (but don't know personally) Brehme. What has become of his diagram? Does he still use and advocate his diagram?
I'm not sure. I think he still thinks its a good idea though and its used in his own text.

I was planning on EJP as my next stop. Thanks for the reassurance.

Pete
 

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