Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Gravitomagnetism !

  1. Nov 16, 2006 #1
    In the latest issue of New Scientist (11 November), there is an interesting article on gravitomagnetism, which has apparently been demonstrated for the first time in a laboratory (see http://www.arxiv.org/abs/gr-qc/0603033 and http://www.arxiv.org/abs/gr-qc/0610015 ). The observed effect is 17 orders of magnitude than the prediction of GR !
    Last edited by a moderator: Apr 22, 2017
  2. jcsd
  3. Nov 16, 2006 #2
    ARXIV is an eprint server, not a journal. Says there the paper is just "submitted to...", no peer review yet. I'll wait to see if this stands up to the most basic scrutiny (which it likely may not) before giving it any consideration - especially after so many "gravitomagnetic" effects turned out to be scams and publicity stunts (Podkletnov, anyone?). And their going to New Scientist with grandiose announcments before conferring with peers is not a good sign.
    Last edited by a moderator: Nov 16, 2006
  4. Nov 16, 2006 #3
    They have submitted their paper to the journal Physica C and they have been attending conferences to talk about their work. They claim that several other research teams will try to reproduce their work and that the results could be out in a year or so.
    But I agree that one should be very cautious. It is essential that other groups can reproduce the results.
  5. Nov 16, 2006 #4

    George Jones

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Although I don't think that GR is necessarily the last word on anything, in this case, I'll bet on GR.

    A pizza with "the works", please.
    Last edited by a moderator: Apr 22, 2017
  6. Nov 16, 2006 #5
    Is it just me or is anybody else naturally suspicious of papers on the ArXiv that have been typed in Microsoft Word?
  7. Nov 16, 2006 #6
    I have seen, that it is actually quite common among the GR-conflicting papers :smile: .
  8. Nov 17, 2006 #7
    Personally, I do not see the relevance of the format of the paper to its scientific content. Has anyone actually read the papers ?
    From reading the papers, realizing the complexity of the experiment, the effort which has been made in analyzing in depth all possible errors, the referenced literature, and considering the institutes involved, it gives to me a very serious impression. I certainly do not feel that they are trying to impress or mislead others. Instead they invite others to repeat their measurements.
    While the signal to noise ratio in their experiment is not very high, it is impressive that they only see the effects at low temperature when the ring becomes superconducting. As to their theoretical explanation, based on gravitons acquiring mass, I am very sceptical. I do not believe that gravitons exist at all.
  9. Nov 19, 2006 #8

    Chris Hillman

    User Avatar
    Science Advisor

    Consider the source

    Hi again, notknowing,

    I strongly advise you to be VERY wary of what you read in New Scientist! This was once a fine magazine, but in recent years has become increasingly infested with uncritical and ill-informed articles which have terribly misled their readers. You might recall the recent flap over Justin Mullin's article in NS on claims by one Roger Shawyer, which has been widely (and justifiably) criticized by many physicists. Indeed, I just noticed a new post by Marc Millis in sci.physics.research, in which he describes why he dismissed Shawyer's claims without a second glance. (Millis once headed the now defunct Breakthrough Propulsion Physics Program at NASA, so he certainly cannot be accused of being unwilling to consider even extremly outre ideas!) Other physicists have offered detailed rebuttals, however--- probably more detailed than the subject really deserves, in fact.

    I think you misunderstood coalquay404's comment. His point (and I have noticed the same phenomenon he did) is, I think, that arXiv eprints which are not formatted in Tex (or LaTeX) are much more likely to be of poor quality. No-one claimed this is a law of Nature; rather, we are talking about statistical likelihoods. Some archive eprints formated in MS word are valuable (if rather clunky in appearance); many formatted using TeX are Dreck. He offered a rough rule of thumb (and I second the advice); take it for what it is worth.

    As for the Tajmar et al. eprints you wanted to discuss, any claims that gtr is off by 17 orders of magnitude should always be treated with great caution. Extraordinary claims require extraordinary evidence, and as Tajmar et al. themselves acknowledge, their work has not yet been confirmed by other groups. In addition to the lessons of history, there are also some specific reasons to be suspicious of their claims, but I don't wish to get into that: I just wanted to add my voice to those urging general caution concerning claims to have found a grossly incorrect laboratory scale violation of gtr.

    I wish it were not neccessary for me to add that I am NOT claiming "gtr is true" (indeed, I hold that such claims don't even make sense). I am claiming that gtr might turn out to give incorrect predictions concerning certain phenomena (indeed, past history and specific well established physical reasoning both imply that we should EXPECT this to happen at some point), but Tajmar et al. are not likely (in my estimation) to have produced the first clear experimental limitation on the validity of gtr.

    Chris Hillman
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook