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Purported Relativity Paradox Resolved 128

sciencehabit writes "A purported conflict between the century-old theory of classical electrodynamics and Einstein's theory of special relativity doesn't exist, a chorus of physicists says. Last April, an electrical engineer claimed that the equation that determines the force exerted on an electrically charged particle by electric and magnetic fields — the Lorentz force law — clashes with relativity, the theory that centers on how observers moving at a constant speed relative to one another will view the same events. To prove it, he concocted a simple 'thought experiment' in which the Lorentz force law seemed to lead to a paradox. Now, four physicists independently say that they have resolved the paradox."
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Purported Relativity Paradox Resolved

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  • by thephydes ( 727739 ) on Saturday January 26, 2013 @05:16AM (#42699373)
    Science is alive and well in at least the Physics community. Whilst I won't even pretend to understand General Relativity, the questioning of it and discussion about those questions is the true essence of science. facts ->theory->more facts->questions->revised theory. Beautiful!
  • by Anonymous Coward on Saturday January 26, 2013 @06:30AM (#42699521)

    Science is alive and well in at least the Physics community. Whilst I won't even pretend to understand General Relativity, the questioning of it and discussion about those questions is the true essence of science.

    Sigh. General Relativity was not even at question here. Perhaps commenting on Slashdot should require a minimum amount of knowing what one is talking about. AAAHAHAHAHAHAHAHAHHAHAHAHA. Sigh.

    At any rate, electrical engineers tend to view parts of Special Relativity in isolation. That makes them easier to handle and "visualize" in some respects, but much harder to deal with interactions. Minkovsky vectors and tensors are what theoretical physicists use instead, grouping several codependent field parts into one entity that can then be transformed as a whole.

    So the physicists will most likely just have employed a better mathematical toolbox for resolving the "paradox". I've not actually read the original Einstein papers, but I would not be much surprised if his equations were closer to what Electrical Engineers get to deal with than what Theoretical Physicists do. Shaking out all that tensor stuff is more or less elegant wrapup work.

    That sort of approach was, however, at the core of General Relativity, and mastering it took quite a bit more time for Einstein. I seem to remember that he discussed the underpinnings with Hilbert, and Hilbert came up with the general equations independently within something like a week, but retracted his papers out of respect for Einstein doing all the visionary groundwork as well as shouldering the math (though being quite slower at it than well-versed mathematicians).

  • It's not a paradox (Score:5, Insightful)

    by mocm ( 141920 ) on Saturday January 26, 2013 @09:40AM (#42700041) Homepage

    if you forget part of the energy-momentum tensor when you transform your coordinates from a stationary into a moving frame of reference.
    Special relativity really cannot "clash" with the Lorentz force law, because it is based on the Lorentz invariance of Maxwell's equations. I think a "paradox" like this keeps coming up ever so often in discussions of special relativity, form people who don't understand it. I just don't see how PRL can accept such a paper.
    I admit it would make a nice problem for a physics test, but not much more.

  • by EzInKy ( 115248 ) on Saturday January 26, 2013 @09:43AM (#42700055)

    You worry too much about silly shit. Some of the best and most insightful posts here are from "Anonymous Cowards".

  • by maxwell demon ( 590494 ) on Saturday January 26, 2013 @10:07AM (#42700155) Journal

    I don't like spending modpoints on anonymous cowards.

    Why not? Moderation is done for the sake of the readers, so they can more easily spot posts which may be worth reading. This primary function of moderation is independent of someone posting as AC or not.

    Moderation also has secondary effects on the posters, to encourage writing good posts. For logged-in users, it changes their Karma. For ACs, it affects the number of allowed posts that day (and probably also the time until the next post is possible) from the same IP. While the effect is not the same for logged-in posters and ACs (and in particular, for ACs it is no lasting effect), there is an effect on ACs as well. Thus even if you only care about the secondary effects, moderating ACs makes sense.

  • by bill_mcgonigle ( 4333 ) * on Saturday January 26, 2013 @10:23AM (#42700237) Homepage Journal

    And it's a healthy sign that some random guy can say, "look Special Relativity seems to be broken," and nobody starts screaming about golden idols or anything, but rather four smart guys kindly consider what he has to say and show him where he went wrong. Everybody learns something, egos remain intact, and nobody starts swinging guns. Science FTW.

  • by exploder ( 196936 ) on Saturday January 26, 2013 @10:34AM (#42700291) Homepage

    First of all, this post is aimed not at the engineer from the article, but at some of the posters to this story and others like it. What is it about physics in particular that attracts so many uneducated crackpots? It seems to be the sweet spot for cranks on the XKCD spectrum--they don't go all the way over to math, and try to promote their pet tensor analysis theory ("this is how we really should compute the induced map on the cotangent bundle!"), and even less often are we treated to their "revolutionary" theories of hydrocarbon structure or ribosomal protein synthesis.

    Nope, they gravitate straight to physics. Is it that concepts are (relatively) familiar, like light, gravity, time, particles, etc? Is it Star Trek? Must drive physicists nuts.

A complex system that works is invariably found to have evolved from a simple system that works.