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Author Topic: On the concept of relativistic mass  (Read 5576 times)

Offline Pmb

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On the concept of relativistic mass
« on: 02/05/2012 19:11:19 »
The subject of this thread is On the concept of relativistic mass which is located at http://arxiv.org/abs/0709.0687. I am the author of this article.

The purpose of this thread is to determine the usefulnes of posting this article, or something similar, when I a new thead is started in the physics forum with the same or similar subject. To date the article as seemed worthless, perhaps for the following reasons;

1) The posters in those threads do not have a level of understanding of the physics involved which is required in understanding the article.
2) The posters in those threads do not have a level of understanding of the mathematical physics which is needed to understand the article.
3) The posters do not find the article to be of any worth.
4) Something else which I haven't been unable to determine as of yet.

It seems only natural that if someone doesn't understand the material required to understand the article then they might feel inadequate in responding to the content of the article. Many-a-time I myself have felt inadequate, and for that reasona ashamed to responding to it. Perhaps to the level I am not up to in order to understanding the material.

It'd be nice to have a better understanding of these scenarios so that the next time the topic, or something similar, I/we cold have a better way to help the poster asking the question.

There are two problems that exist in posting the article (1) I write another article but leave the math out or (2) I write another article leaving the math in but downplay the physics.

Any thoughts as to a resolution of this problem?


 

Offline yor_on

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Re: On the concept of relativistic mass
« Reply #1 on: 02/05/2012 22:07:57 »
It's in no way worthless Pete, although the math you use in the pdf only will be understood by a selected few here. After all, you refer to Einsteins field equations and fluids. Break it down as good as you can, to keep it reader friendly you might want to explain the way you yourself started to wonder about it, when you first wanted a discussion opened about the modern definition of 'mass', what you want to be referred to as its 'proper mass', if I get you right? 
 

Offline butchmurray

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Re: On the concept of relativistic mass
« Reply #2 on: 02/05/2012 22:16:37 »
I agree. Edit it for the audience and post it. The only way to know what will happen is to post it and see what happens.
 

Offline Pmb

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Re: On the concept of relativistic mass
« Reply #3 on: 03/05/2012 01:50:48 »
It's in no way worthless Pete, although the math you use in the pdf only will be understood by a selected few here. After all, you refer to Einsteins field equations and fluids. Break it down as good as you can, to keep it reader friendly you might want to explain the way you yourself started to wonder about it, when you first wanted a discussion opened about the modern definition of 'mass', what you want to be referred to as its 'proper mass', if I get you right? 
The problem in the past is that I go to a forum, such as this one, in which I don't know who the people reading the post are or what their background is. How is a person to know what to post and what not to post if I don't know what the  physics understanding of the general person who is reading the post is?
 

Offline Pmb

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Re: On the concept of relativistic mass
« Reply #4 on: 03/05/2012 01:52:22 »
I agree. Edit it for the audience and post it. The only way to know what will happen is to post it and see what happens.
How would I know who the audience of the post is or what their training in relativity is as well as their training in the related math?
« Last Edit: 03/05/2012 01:55:23 by Pmb »
 

Offline MikeS

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Re: On the concept of relativistic mass
« Reply #5 on: 03/05/2012 12:03:25 »
Another point Pete.

If people don't agree with your viewpoint and they probably wont, or you wouldn't be posting in new theories, they are free to debate but I have found, mostly you get ignored.  Without feedback we learn nothing.

The things I post, lack the mathematical proof but are normally very simple ideas, as simply put as I can.  I still get the impression that most people don't have a clue what I am talking about but without feedback I am unsure.  When I am wrong I would like to be made aware of it by being showed the evidence in a non-condescending manner.  That very seldom happens.  Some things we just have to do.
 

Offline Pmb

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Re: On the concept of relativistic mass
« Reply #6 on: 03/05/2012 14:52:27 »
If people don't agree with your viewpoint and they probably wont, or you wouldn't be posting in new theories, ...
The reason I posted this topic here is that someone recommended that I do so. My first instinct was to post it in the physics forum. I eventually came to agree with them because if I decided to post in the physics forum people would almost certainly assume I wanted to debate the subject and I'd never be able to discuss what I really wanted to.It's happened to me before several times.
The things I post, lack the mathematical proof but are normally very simple ideas, as simply put as I can.  I still get the impression that most people don't have a clue what I am talking about but without feedback I am unsure.
That's exactly how I feel myself!
 

Offline Phractality

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Re: On the concept of relativistic mass
« Reply #7 on: 03/05/2012 17:19:38 »
 
Peter,
 
If I've said it once, I've said it a hundred times; I'm no mathematician. I do pretty well with integral calculus, but not difEQs, and I don't get tensors, at all. So I'm pretty much handicapped in general relativity. I get the concept of redefining space and time in terms of the path of light. I'm not comfortable thinking in terms of warped space-time, even though I have a conceptual understanding of it.
 
My intro to special relativity in 1967 used the term "relativistic mass" to mean the mass gained due to velocity; in other words, the difference between a particle's mass in its own frame of reference and its mass in a different inertial frame of reference. I didn't really understand relativity until decades later, when I read some of Einstein's work on my own, without having it "explained" to me by a nutty professor.
 
I've read discussions of relativity in which "m" represents rest mass, and relativistic mass is "γm", meaning total mass in an observer's reference frame, i.e. rest mass plus the increase due to velocity. In other discussions, rest mass is "m0", and "m" is total mass in the observer's reference frame; m = γm0. So the problem is not disagreements about the science as much as it is about a lack of uniformity in nomenclature.
 
There are many writings out there, already, using different symbols to represent the same thing, and the same symbols to represent different things. There is also the well-established fact that "m" represents "meter". If an international governing body declares that one set of existing symbols is correct, that will not clear up the confusion until the new convention is universally adopted and the old lack of convention is forgotten. Anyone reading an old unconventional writing will have the responsibility to decipher what system the author used. Publishers will have a duty to annotate those old writings, explaining what the symbols meant to the author.
 
Perhaps it would be better to invent new symbols, which have not previously been used to mean anything other than what the new convention demands. In particular, the symbol "m" will is likely to be misinterpreted, unless the reader makes an effort to determine whether it is used in the new conventional way or an old unconventional way.
 
I am comfortable with the symbol "m0" for rest mass. As far as I know, it has no other meaning in literature about relativity. On the other hand, "m = γm0" probably should be changed to something like "mt = γm0". If "mt" means the total mass in an observer's reference frame, and if that symbol has not been used in the past to mean something else, then its meaning would be immediately obvious to the reader.
 
As for actual scientific disagreements:
 
·       There is the dispute over whether the photon has inertial mass and/or gravitational mass. I accept, without understanding, that a photon has no mass in the context of warped space-time; but in the context of Euclidean space and time, the photon MUST have both inertial and gravitational mass. Defining force as the rate of changing momentum, f = dp/dt, gravity exerts an attractive force on a photon. To conserve momentum, the photon must exert an equal and opposite force on the source of that gravity, so the photon has gravitational mass. Likewise, inertia should be defined in terms of momentum, not velocity; it takes force to alter a photon's momentum, so the photon has inertial mass. Also, a photon does change direction in Euclidean space as it passes near a gravity well. It's velocity (not speed) is different when it emerges on the other side, so it has accelerated. A photon does not accelerate in Minkowski space-time because its path is the definition of a straight line.
 
·       There is also the dispute over whether gravitational mass of a particle is the same in all reference frames or whether it is proportional to relativistic mass. It seems to me that time dilation of a simple two-body gravitational system (e.g. a planet and moon) demands that relativity increases inertial mass but not gravitational mass of the two bodies toward one another. Consider a pair of equal masses orbiting one another due to their mutual gravity. In a recent thread, I took the example of two space ships, each with a mass of 1000 tonne, 100 m apart. In their own inertial reference frame, they orbit once every 107 hours. In a reference frame where gamma = 10, that orbital period becomes 1070 hours because of time dilation. Therefore, they accelerate toward one another ten times slower. If their gravitational mass and inertial mass both increased tenfold, they would accelerate toward one another ten times faster and orbit one another every 10.7 hours. Perhaps the two orbiting bodies do exert ten times as much gravity on a body which is at rest in the observer's reference frame; I haven't figure that one out.
 
 

Offline butchmurray

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Re: On the concept of relativistic mass
« Reply #8 on: 04/05/2012 00:15:32 »
I agree. Edit it for the audience and post it. The only way to know what will happen is to post it and see what happens.
How would I know who the audience of the post is or what their training in relativity is as well as their training in the related math?
There is a diverse group here. It may be understood by some. It may not be understood by any one. You have nothing to loose except a little time. 
 

Offline yor_on

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Re: On the concept of relativistic mass
« Reply #9 on: 04/05/2012 13:27:29 »
Yeah Pete. keep it as simple and sweet as you can.
Doesn't mean that you should avoid mathematics though, but make it worth to read for those that doesn't have the math skills too. Physics ain't easy, but it's the best game in town.
 

Offline Pmb

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Re: On the concept of relativistic mass
« Reply #10 on: 04/05/2012 22:32:47 »
Yeah Pete. keep it as simple and sweet as you can.
Doesn't mean that you should avoid mathematics though, but make it worth to read for those that doesn't have the math skills too. Physics ain't easy, but it's the best game in town.
Yeah, but how am I to tell who would understand even simply math and who wouldn't? Sometimes it only requires simple mathmatics to get a point through. In the past this has proved to be a bridge between enough math and not enough. It's a small line.
« Last Edit: 04/05/2012 22:35:40 by Pmb »
 

Offline MikeS

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Re: On the concept of relativistic mass
« Reply #11 on: 05/05/2012 06:47:19 »
The way I see it is Math is a language, the best there is for science.

Like any language it can be used to (but does not 'necessary') tell the truth.  Used in conjunction with ordinary language both can express the same idea.  One confirms the other.  If an idea can be expressed through math then it should be possible to express it through conventional language. 

Express the idea in conventional language and confirm or elaborate it in math.  If you can form an idea in your mind and convert it into math, ok.  If you formulate it in your mind in math but cannot express it in conventional language then there is no double check on the correctness of it.
 

Offline Ęthelwulf

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Re: On the concept of relativistic mass
« Reply #12 on: 06/05/2012 09:44:05 »
The subject of this thread is On the concept of relativistic mass which is located at http://arxiv.org/abs/0709.0687. I am the author of this article.

The purpose of this thread is to determine the usefulnes of posting this article, or something similar, when I a new thead is started in the physics forum with the same or similar subject. To date the article as seemed worthless, perhaps for the following reasons;

1) The posters in those threads do not have a level of understanding of the physics involved which is required in understanding the article.
2) The posters in those threads do not have a level of understanding of the mathematical physics which is needed to understand the article.
3) The posters do not find the article to be of any worth.
4) Something else which I haven't been unable to determine as of yet.

It seems only natural that if someone doesn't understand the material required to understand the article then they might feel inadequate in responding to the content of the article. Many-a-time I myself have felt inadequate, and for that reasona ashamed to responding to it. Perhaps to the level I am not up to in order to understanding the material.

It'd be nice to have a better understanding of these scenarios so that the next time the topic, or something similar, I/we cold have a better way to help the poster asking the question.

There are two problems that exist in posting the article (1) I write another article but leave the math out or (2) I write another article leaving the math in but downplay the physics.

Any thoughts as to a resolution of this problem?

Worthless...? No. Uninteresting? Perhaps.

There is not enough math in there either. I'd think about more math in a future presentation. Just some friendly criticism.
 

Offline Ęthelwulf

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Re: On the concept of relativistic mass
« Reply #13 on: 06/05/2012 09:46:58 »
The way I see it is Math is a language, the best there is for science.


Maybe so, but recently your threads have been largely speculative without any math content.
 

Offline MikeS

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Re: On the concept of relativistic mass
« Reply #14 on: 06/05/2012 12:42:25 »
I would not say speculative as they are based on sound principles.

Many theories that rely heavily on the Math content are and have been speculative.
 

Offline Ęthelwulf

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Re: On the concept of relativistic mass
« Reply #15 on: 06/05/2012 12:49:10 »
I would not say speculative as they are based on sound principles.

Many theories that rely heavily on the Math content are and have been speculative.

Sure, but a theory (unless it really requires it) normally should require some math. If you are willing to make rather bold assertions about something, you really should require the math - otherwise its mostly buzzwords being thrown about.
 

Offline JP

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Re: On the concept of relativistic mass
« Reply #16 on: 06/05/2012 14:24:36 »
Modnote: Ęthelwulf, please keep the thread on discussions of science.  Hijacking the thread to attack MikeS over the math content of his theories is not acceptable.
 

Offline Pmb

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Re: On the concept of relativistic mass
« Reply #17 on: 06/05/2012 17:02:12 »
There is not enough math in there either. I'd think about more math in a future presentation. Just some friendly criticism.
That is quite incorrect. Since the thread is about an online article whose URL is given then it is assumed you at least browsed through it. Claiming that there is not enough math their either. is simply a grossly exagerated assertion.
 

Offline Ęthelwulf

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Re: On the concept of relativistic mass
« Reply #18 on: 06/05/2012 17:35:23 »
Well, how much math should there be? Just as you have it, no more and no less?

 

Offline Ęthelwulf

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Re: On the concept of relativistic mass
« Reply #19 on: 06/05/2012 17:37:30 »
Well, how much math should there be? Just as you have it, no more and no less?

Interested in why you were defending it, I looked at the work again. I don't know what happened the other day, but when I looked at the work it seemed a lot less. Perhaps equations had not downloaded or something. Either way, I've seen them now and I agree, there are enough equations.
 

Offline Phractality

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Re: On the concept of relativistic mass
« Reply #20 on: 08/05/2012 06:38:57 »
PMB,
In the ARXIV article, you talk about active and passive gravitational masses. I believe they must always be equal. Otherwise, momentum would not be conserved. If A pulls on B harder than B pulls on A, then B's momentum will change more than A's momentum changes.
This must be true of both photons and particles with proper mass. A photon has momentum, and a change of direction is a change of momentum. When a photon passes close to a star, the photon's direction changes, so the star's gravity has imparted momentum to the photon. To conserve momentum, the photon must have gravitational mass, and the photon's gravity must impart equal and opposite momentum to the star.
Do you claim that momentum is not conserved? How else can active and passive gravitational masses be unequal?
 

Offline Pmb

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Re: On the concept of relativistic mass
« Reply #21 on: 08/05/2012 09:16:18 »
PMB,
In the ARXIV article, you talk about active and passive gravitational masses. I believe they must always be equal. Otherwise, momentum would not be conserved.
And who said that they were otherwise? I don' believe that I did. If you think I did then please give me the page number, the paragraph number and equation number, if possible. They're equal theoretically. They're not equal by definition.

The total active (agm) and total passive gravitational mass (pgm) of a system have the same value. However, as I pointed out in the paper, the densities are quite different. they don't need to be the same. However the total values are not the same by definition but by theory. That is to say, one has to measure each of them to find their value. One can't simply measure one and assume the other is the same by definiton. After the theory becomes well accepted and the values have long been valued to be the same then they can be assumed to have the same value.

If A pulls on B harder than B pulls on A, then B's momentum will change more than A's momentum changes.
Yep. Pretty obvious I'd say. Again, do you claim that I said differently?

Do you claim that momentum is not conserved?
No. Do you think I claimed otherwise?

How else can active and passive gravitational masses be unequal?
Who said they ever were? As I recall, I wrote that they are deffined differently but have the same numerical value. Did you not read that? Please provide the page numberm paragraph number and equation number, if possible, where I claimed anything different. Thanks.
« Last Edit: 08/05/2012 09:34:14 by Pmb »
 

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Re: On the concept of relativistic mass
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