Relativistic Mass

Discussion in 'Physics & Math' started by Little Bang, Jul 1, 2015.

  1. OnlyMe Valued Senior Member

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    Bruce, if you take both Little Bang's OP and his second post as an indicator,

    it seems more like he was asking about a mass (as in particle) moving past the observer at a relativistic velocity. So the question was really would the particle's relativistic velocity increase its gravitational field to the point that it would affect or be detectable by an observer.

    Obviously if a large mass, with a significant inherent gravitational field, moved through the solar system at a relativistic velocity, it would have a significant affect on the orbital dynamics of the system as a whole.., but would its gravitational field be greater than if it had only a classical velocity? I think not... Still the near loght speed changes in the overall field dynamics would be significant.
     
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  3. brucep Valued Senior Member

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    It comes from the theory. Something you don't understand. The energy momentum tensor defines everything that effects the local spacetime curvature.
    https://en.m.wikipedia.org/wiki/Stress–energy_tensor#Identifying_the_components_of_the_tensor
    The reason I write that down is because you, and others, are spewing bullshit about what effects the spacetime curvature [gravity]. The OP asked whether the relativistic mass of an object effects the observer. It does because it just expresses the total energy of the object which is a component of the tensor Einstein used to describe what effects the spacetime curvature. Some really stupid answers in this thread.
    E=M + p
    When p = 0
    E=M
    E/M = 1
     
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  5. OnlyMe Valued Senior Member

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    Bruce, you can toss out all of the math and theory about spacetime you want to.., and still without pointing to observations that involve dark matter (which remains an unknown), you cannot point to any gravitational field that does not involve a massive object. At least not one that is real and observable!

    Einstein developed his field equations to describe the gravitational fields of real objects and how those objects interact gravitationally. And there has been a great deal of theoretical speculation about what the implications might be. Not all of which are in agreement.
     
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  7. brucep Valued Senior Member

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    I answered what he asked. The relativistic mass is an equation that models the total energy but calls it relativistic mass. Professor Strassler provided a list of reasons why it's sloppy physics. Oh well. Much later.
     
  8. brucep Valued Senior Member

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    You're just another type of crank needing to defend your overall illiteracy on the subject. Dark matter is a component of the stress energy tensor. That's why it shows up in lensing experiments. If it wasn't it wouldn't have any gravitational interaction.
     
  9. OnlyMe Valued Senior Member

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    Bruce, you have to know, because you are not stupid, that you are posting on a lay oriented forum.., and just because you understand what is meant in modern physics by the term relativistic mass, does not mean that that is what most lay persons understand the phrase to mean.

    I may have been mistaken but it has been my interpretation of the discussion that the lay oriented question was based on a lay interpretation that the real mass of an object increases with its velocity.., and in a manner that its gravitational mass also increases.
     
  10. tashja Registered Senior Member

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    715
    Hi, Little Bang. Hey, guys.

    Q, you mentioned Prof. Carlip's paper, so I thought it a good idea to contact him. Below is his reply:

     
    RajeshTrivedi and Q-reeus like this.
  11. paddoboy Valued Senior Member

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    As per all the expert references you have troubled yourself to obtain tashja, you've again excelled ....Vinaka vakalevu!

    Please Register or Log in to view the hidden image!

     
  12. Q-reeus Banned Valued Senior Member

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    Thanks tashja for that reply from Prof Carlip, which of course backs my position. Unfortunately it has not so far resulted in honest retractions from the posters who earlier flatly denied what Carlip and myself had to say. Nothing knew there. I expect either sullen silence or distraction from such types. Evidently the important thing is not truth but the putting down of certain members at all costs. As I said earlier in #58, in this instance Rajesh had it basically right - though I very much doubt he understood the full details correctly.
     
  13. paddoboy Valued Senior Member

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    I see both sides having it basically right and that is reflected not only in Professor Carlip's post, but other reputable expert links.

    It depends on the setting. In general relativity, gravity
    is considerably more complicated than in Newtonian theory,
    and in particular is not always a central force. There
    are gravitational analogs of magnetism, and a moving mass
    has a gravitomagnetic field that becomes strong as the
    speed approaches c. So the answer depends on the details
    of how this and the "Newtonian" part of the field combine.

    If a mass is simply moving past you at a constant velocity,
    you can always go to a frame in which it's at rest and
    you are moving past it. The amount you're deflected goes
    a (1+v^2/c^2), so as the relative speed gets very large you
    can get roughly twice the gravitational effect, but no
    more. This is because of a cancellation between "Newtonian"
    and gravitomagnetic effects.

    On the other hand, if you have a *contained* collection
    of masses that are moving relative to each other but
    whose center of mass is stationary, then the gravitational
    field depends on their relativistic mass. So, for example,
    if you have a box of gas and heat it up, its gravitational
    mass will increase.

    You can find a more detailed discussion in my paper


    Kinetic Energy and the Equivalence Principle

    Steve Carlip
     
  14. OnlyMe Valued Senior Member

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    Actually Q-reeus, though I had not seen Carlip's paper before and have not had time to look at more than the first page or so, it does appear that it would be a good reference if you chose to open a thread on the issue you raised earlier and was mentioned in his response to tashja's email... Namely the issue of heat adding to the weight of an object. Note I said weight because I still maintain that the mass itself remains constant... And any difference in weight is a reflection of total energy not a change in mass... But as I tried to say earlier I think that discussion deserves a thread of its own.

    I don't believe it settles the issue here, which is more about the definitions of mass and relativistic mass! Historically it was thought or assumed that the mass of a moving object did actually increase, with velocity, but that was pre-GR.

    Strictly, from the context of GR as it is understood today, the term relativistic mass is total energy, and there is no problem.

    The problem is being clear that you are talking about total energy or a real increase in mass!

    From the way I read it, or perhaps because it is what I expect from Carlip and Bruce was clear on the issue, both are referring to the modern interpretation and definition, within the contex of GR... Still neither Little Bang nor Rajesh has stepped up to say that I was wrong in how I understood their implied definition. Rajesh was fairly insistent that mass itself does increase with velocity.., not just that relativistic mass refers to an increased total energy, and that both energy and mass contribute to a gravitational field.

    Still the argument in the later portion of the discussion changes nothing relative to the question in the OP, because there are no conditions that the gravitational field of a particle, which Little Bang specified in his second post, would affect an observer no matter what velocity is passed by at..... And it is unreasonable to believe that any object with a large enough mass that its gravitational field could even be detected, could survive intact at any relativistic velocity. I don't have hands on a reference but atoms should begin to ionize at perhaps as little as 20% to 30% the speed of light. And we certainly have no experience with any gravitationally significant mass, with anything more than a classical velocity.
     
    Last edited: Jul 3, 2015
  15. OnlyMe Valued Senior Member

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    I believe that Bruce, Strassler and Carlip were all assuming the modern interpretation and definition of relativistic mass.

    The reason I link Okun's paper from time to time is that he deals with the issue more from the historical perspective and the potential for misunderstanding that including the word mass in the term generates in discussion where not all parties understand the history and modern use, interpretation and definition.
     
  16. RajeshTrivedi Valued Senior Member

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    1,525
    I did brought out in the first instance or so that relativistic mass is [gamma times rest mass], and this does effect the Stress Energy Tensor and thus having the impact on spacetime curvature/distortion.

    From the word go, you were stuck with Relativistic Mass = Momentum, which is incorrect.

    Pl see the abstract (it is somewhat different from OP, but does convey the meaning), most of the arguments which you and Paddoboy attempted to project about rest mass and Gravitational mass fall apart, with this alone...

    http://adsabs.harvard.edu/abs/1985AmJPh..53..661O


    PS1: Prof Carlip's para #1 and para #2 is an extension of the above abstract but in the last para distinguishes between a single isolated particle and a system of mass, which also conveys the meaning, but a different aspect altogether.

    PS2: I am still wondering, How and where did you get 'Relativistic Mass = Momentum'.
     
  17. RajeshTrivedi Valued Senior Member

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    1,525
    ....

    I like it.
     
  18. RajeshTrivedi Valued Senior Member

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    I would have appreciated if you had seen the hostility shown by AlexG, OnlyMe and of course by my old pal Paddoboy.....Just because my stand was opposing to theirs (and rightly so), they all started advising 'Little Bang' to either put me on ignore or take my opinion with a pinch of salt. And of course you know these posters' Physics (or lack of it) from previous thread and the same gets established with this thread too. Still to a larger extent you are right in your prescription that is Science is meant to be about discovery and models of the world, not egos, whether yours or anyone else's. But then can you alienate ego from human beings ? May be you can do some research and synthesize a chemical which could do this.....Enjoy, stay as long as you enjoy.
     
  19. RajeshTrivedi Valued Senior Member

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    The main problem between both of them is lack of knowledge !!

    You are acting like a bloody spoil brat..There is not even a single member to whom you have not spewed venom...barring that Paddoboy. Mods warned you but....You are an absolute intellectual dishonest crank, who likes and tolerates only paddoboy's nonsense...Look at OnlyMe, how the poor fellow is trying to be subservient to you like Paddoboy, still you are throwing him out like a fly..Grow up, kid, or as I told you earlier, take mental assistance before it gets too late....I know couple of shrinks down under, I can do the recommendation part for you.
     
  20. paddoboy Valued Senior Member

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    27,543

    That's where you posted your "paper"was it not?
    And besides other links support both interpretations as I have said.
    My first post at 21 went like this.....
    Not at all.
    Rest mass, or the measured mass, does not change with velocity.
    And that is what contributes to the gravitational field.
    Relativistic speeds changes the relationship between momentum and energy.


    Lev Okun's, The Concept of Mass (http://www.itep.ru/theor/persons/lab180/okun/em_3.pdf) covers the issue.
    .


    http://arxiv.org/abs/hep-ph/0602037

    Perhaps your record on this forum proceeds you..Perhaps the amount of times
    that you have been seen as totally wrong and yet can never have the decency,
    the morals, or the intestinal fortitude to admit error, has people preempting
    your nonsense, and refusing to give you any leeway because of that arrogance.
    I thought exchemist, not being a hot head like you and me, actually hit the nail
    right on the head with his realistic summation


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    And the above proves why you are held in such contempt on this forum...your pretentious nonsense as shown over many threads, your arrogant bull headed nature, and your great ability in handling the truth lightly.

    Your half victory here for being half right, after so many wrongs over many months, as detailed by professional experts, will I dare say, not improve your attitude one bit.

    Oh, and Rajesh, what happen to your second paper that was supposed to resurrect the demolished first paper?
     
    Last edited: Jul 3, 2015
  21. paddoboy Valued Senior Member

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    27,543
    Well why didn't you say it?
    Why go on like a little school girl?
    And just to address your little rant previous...bruce wisely has you on ignore as two others do.
    And as I have told you previously, the lies you tell and your general persona on this forum, [along with mine and bruce's] will be judged by your peers Rajesh. Or are you too isolated in your ivory tower to see that and recognise that fact.
     
    Last edited: Jul 3, 2015
  22. OnlyMe Valued Senior Member

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    3,914
    Rajesh, the idea or concept of relativistic mass predates GR, and within the context of SR is frame dependent. While a particle's rest mass is not frame dependent.

    As the term is used in GR today (by those who still use it), it is used to refer to an object's total energy, not just its mass. That total energy includes the velocity, not just mass.

    While there might be technical arguments why momentum and relativistic mass are not the same, in any lay discussion there is no real difference. They both refer to total energy. The total energy increases with velocity. The mass remains constant.

    As Carlip mentioned when considering gravitomagenic effects, relativistic velocities would increased the effects of the gravitomagnetic aspect of the field... But that is not a simple issue and is not really the same as implying that the gravitational field, which I believe he referred to as the Newtonian field, gets greater or stronger. It starts to involve things like frame dragging. As example, if the earth we're spinning on its axis faster, it's gravitational field would not be greater, but the frame dragging effect would be more dramatic. An object would still fall at the same rate but the spin would deflect the fall more in the direction of the spin.

    So I said relativistic mass would be better defined as momentum, than as mass, because it is more than just mass.... And to be honest it would be better to just discard the term in a lay discussion because the word mass in the relativistic mass, carries baggage and makes the term easily misunderstood. Remember you are posting on a lay oriented forum.
     
  23. RajeshTrivedi Valued Senior Member

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    1,525
    You understood the point !! Lets put a brake, otherwise Paddoboy would again start with his copy paste...
     

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