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Looking for sources for deprecation of relativistic mass

  1. Dec 8, 2015 #1
    I am interested on the earliest reference on the deprecation of the concept of relativistic mass. AFAIR even Einstein used relativistic mass and the somehow related concepts of transversal and longitudinal force. I am trying to find a long lost article about showing all these concepts related and why the concept had to be deprecated. Cannot remember either author or journal. Thanks!
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  3. Dec 8, 2015 #2


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  4. Dec 8, 2015 #3
    Thank you very much. I think it is Okun what I was looking for. Maybe a later paper than that which is referenced in Wikipedia. I recall having the impression that still the concept of relativistic mass was being used and that longitudinal and transversal mass had been predated even earlier.

    There are even quite modern divulgation books in which the relativistic mass concept is used to explain why you cannot accelerate a body up to the speed of light. Okun has a very deep understanding on relativity, I recall a famous paper on AJP in which the concept of the photon losing energy as it climbs a gravitational field is ridiculized to the extreme.
  5. Dec 8, 2015 #4
    I have learnt that L. Okun just died two weeks ago. He was 86. A pity, as I said he had great ideas on relativity and had the concepts much more clear than other often acclaimed authors.
  6. Dec 8, 2015 #5


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    After I posted, I thought of Okun's paper, too, but I wondered if it's too recent for your needs.

    Just as an anecdotal data point, I was a graduate student in experimental high-energy particle physics 1977-1983. We worked with highly relativistic particles. I don't remember any of us (grad students or professors) ever using "relativistic mass", except in one textbook on accelerator design that was originally written around 1950 by someone who had probably learned relativity in the 1920s or 1930s.
  7. Dec 8, 2015 #6
    I think that it was Okun paper what I read, but had the idea of very early reference in mind.

    Thanks for the interesting anecdota. I don't recall if we used the relativistic mass in the Physics degree, maybe in Physics 101 equivalent. In any case we didn't even study GR except as optional, which is a shame. When I read Okun paper I was very shocked because I had asked a chilean expert on GR about the very same concept and, after thinking a little, recomended me Gravitation book. After reading the passage found that they surely were in error or misleading. Three years later, 2000, I found this paper by Okun. Well...
  8. Dec 8, 2015 #7


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    A bit earlier than Okun: http://sites.fas.harvard.edu/~phys191r/References/b5/Adler1987.pdf

    More anecdote:
    When I was in college in the mid-70s, I only encountered relativistic mass once: Predicting the displacement of a relativistic electron by transverse forces as part of a lab exercise. That would be one of the very few problems that is most easily analyzed in terms of relativistic mass, and I imagine that such experiments were of greater interest early in the 20th century when experimental confirmation of SR was a live topic (http://www.edu-observatory.org/physics-faq/Relativity/SR/experiments.html#electron_mass_variation). Of course by the 1970s that lab exercise was interesting only for a more mundane reason - we weren't going to falsify relativity, but we might falsify the proposition that I was competent to set up an experiment.
  9. Dec 8, 2015 #8
    Well, that paper is very interesting. I don't recall reading it before. The anecdote is interesting, surely the concepts, even if deprecated, hold some inertia to be changed. :)

    I remember I was a little confused when presented with E = sqrt ( m^2c^4 + p^2c^2), because of the unnecesary zero subindex dropped. But cannot recall the confusion to be inspired by divulgation books or outdated textbooks.
  10. Dec 8, 2015 #9

    Mister T

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    There was an interesting round of letters to the editor in Physics Today following the 1989 issue in which Lev Okun's paper appeared. One critic of Okun was Rindler, a strong proponent of the use of relativistic mass, as was the professor I had in my introductory sequence in the 1970's, who was also from Germany as it happens. The professor I had after that for a course in relativity was also a proponent of the use of relativistic mass. I remember the discussion in our textbook (Taylor and Wheeler) denouncing the use of relativistic mass but our professor went to some effort to dismiss that argument. It wasn't until the 1990's when the Okun article came out that introductory textbooks started dropping relativistic mass. It went from being a central part of the theory to being discarded due to "falling out of fashion" to disappearing altogether between 1995 and 2005, or so. Now it is not even mentioned in the vast majority of introductory textbooks.

    The 1987 Adler article is the oldest on the topic that I know of.
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