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Thread: Gravitational Waves, GR and Vector gravity:

  1. #1
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    Gravitational Waves, GR and Vector gravity:

    OK, simply put, I would like some critique of the following paper....
    If this is in the wrong section, I apologize......

    https://arxiv.org/abs/1804.03520

    GW170817 event rules out general relativity in favor of vector gravity

    The observation of gravitational waves by the three LIGO-Virgo interferometers allows the examination of the polarization of gravitational waves. Here we analyze the binary neutron star event GW170817, whose source location and distance are determined precisely by concurrent electromagnetic observations. Applying a signal accumulation procedure to the LIGO-Virgo strain data, we find ratios of the signals detected by the three interferometers. We conclude that the signal ratios are inconsistent with the predictions of general relativity, but consistent with the recently proposed vector theory of gravity [Phys. Scr. 92, 125001 (2017)]. Moreover, we find that vector gravity yields a distance to the source in agreement with the astronomical observations. If our analysis is correct, Einstein's general theory of relativity is ruled out in favor of vector gravity and future gravitational wave detections by three or more observatories should confirm this conclusion with higher precision.

    :::::::::::::::::::::::::::::::::::::::::::::::::: ::::::::

    Is Einstein's GR now ruled out?
    “Imagination will often carry us to worlds that never were, but without it we go nowhere.”
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    ASTRO BOY

    If you are just asking for a critique of the linked paper (but you are not planning to defend the ideas in the paper), then ATM is the wrong section - so I'm moving the thread to Q&A.

    Please be aware that in Q&A you can question the mainstream answers you are given, but only to clarify those answers. You may not advocate a non-mainstream idea in Q&A (your's or this paper's) nor may you use Q&A to cast doubts on the mainstream.

    If you decide you wish to do any of that advocacy, please say so immediately, and this thread will be moved back to ATM (and you will be expected to defend the non-mainstream position.
    Last edited by slang; 2019-Jan-11 at 11:36 PM. Reason: may NOT advocate
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    Quote Originally Posted by ASTRO BOY View Post
    Is Einstein's GR now ruled out?
    It would take a lot more than one paper with some controversial results based on a single observation to show that such a well-established theory is wrong. So no.

    But hopefully, someone can comment in more detail on the content of the paper....

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    I certainly am not advocating the idea, simply need it professionally critiqued for my own edification, as I am not qualified to do so
    “Imagination will often carry us to worlds that never were, but without it we go nowhere.”
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    The paper also claims BH's are not needed, and supposedly explains DE.
    http://iopscience.iop.org/article/10...896/aa93a8/pdf
    Vector theory of gravity: Universe without black holes and solution of dark energy problem

    This is why I need this professionaly debunked, or otherwise.
    “Imagination will often carry us to worlds that never were, but without it we go nowhere.”
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    Quote Originally Posted by ASTRO BOY View Post
    The paper also claims BH's are not needed, and supposedly explains DE.

    This is why I need this professionaly debunked, or otherwise.
    Hms, without specifying in detail what is meant by a black hole, claiming that black holes do not exist seems like a very peculiar leap of logic. For the sake of argument, if the author had claimed that his theory of gravity showed that singularities do not exist, I would have shrugged my shoulders, but when he goes as far as to say black holes don't exist, I can't but squeeze my furry koala butt cheeks together and shred the fabric of space and time with a big rip. As far as I've come to understand, black holes are basically gravitational fields that are so powerful that their escape velocities exceed that of light, which is why they are black, and such objects do not only exist; they have to exist. We have a pretty decent understanding of what kinds of conditions give rise to black holes, the one knowledge gap I can think of being how super massive black holes form and the apparent absence of intermediate sized black holes, but these are gaps to be filled, not evidence against black holes existing. What is up for debate, though, is what the heck goes on beyond the event horizon of a black hole, but whatever it is, it has no bearing on the fact that they exist.

    I believe a certain Carl Sagan said something along the lines of "extraordinary claims require extraordinary evidence", and while I think evidence should suffice - it doesn't have to be extraordinary in any kind of way - I agree with the spirit of his statement, especially when, reading the abstract of the paper you linked to, I came across the following gem "We show that such assumptions yield a unique theory of gravity, it is free of black holes and, to the best of our knowledge, passes all available tests".

    Reeeaaaalllly? I guess the catch in that sentence is the "to the best of our knowledge". I have a question for you... Don't you get a suspicious when you read something like that? No alarm bells go off? You see, I don't actually think you have to be an expert in the field to smell a rat in this particular case. I'm not an expert by any means, but using the "baloney detection kit" advocated by the previously mentioned Carl Sagan, I feel comfortable concluding with a great degree of certainty that the theory in question does not invalidate either our Newtonian or Einsteinian (Is that a term?) understanding of gravity. For example, look at how the journal in which it was published advertises itself: "Physica Scripta, endorsed by The Royal Swedish Academy of Sciences, is an international journal dedicated to presenting novel and accessible research findings across the breadth of theoretical and experimental physics.". It doesn't even appear to have been peer reviewed, this article.

    I can go on and on, but my point is that when you stumble along something like this, do a little bit of digging and ask critical questions, and I'm sure you will reach the same conclusion that I have. You don't have to understand vector dubbidududu chipotle inverted mathematics to be able to tell that the claims made in this article are spurious at best.

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    My take on it, from reading it, is that it is an interesting result but is nowhere near the level of certainty they ascribe it. There are several key areas I think need to be expanded on.
    - The precise physical orientations of the systems (they give a couple of figures but that is probably not enough)
    - The error analysis. This is a big one for me. I would like to see much more on this because there isn't enough detail to validate their use of statistics here.
    - The LIGO noise reduction. They take uncorrected data - but then refer to noise corrections. So something is being done and it is really important to understand what biases they have left in and whether this is causing what they see. By using unwhitened data they are leaving in machine and environmental noise biases - so the ratio of the detection strengths between machines may simply reflect these uncorrected system biases and not a problem with GR
    - More data. Making a conclusion like this from what is effectively a single data point is bad practise. I think that the tone and the conclusions of the paper should have been completely different because of this.
    - They need to better address the fact that someone else concluded something completely different based on a similar sounding analysis. They just dismiss it in a paragraph or so without going into depth
    - Lastly a sensitivity study to their data selection/conditioning is needed. They touch on it at the end of the paper, which is really good (a lot of papers just don't do it) but it is not enough. They need to compare the data after the usual cleaning algorithms and so on

    So while there isn't anything immediately wrong with the paper it is very incomplete for the level of claim it makes. I think there are enough systemic and methodological issues left unexplored that their conclusion cannot be said to be justified based on the presented evidence. More work, more data, more rigorous peer review is required, I think.

    Edit to add: A skimming the abstract for that Vector gravity paper - it seems to have a HUGE leap in it. Unless there is a lot of evidence they just don't mention in the abstract I have a lot of concerns about the wording of it.

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    While I appreciate the answers so far, I'm more concerned with specific errors in the claims and/or maths. My own thoughts are that firstly what it claims and predicts, we as yet do not have the skills or technology to validate it or otherwise. My other criticism is that the definition of a BH is where escape velocity equals "c" and that entails the Schwarzchild radius, at which once reached, further collapse is compulsory. I need the skills of those into the maths of such known facts to invalidate this Vector gravity.
    Any takers?
    “Imagination will often carry us to worlds that never were, but without it we go nowhere.”
    ― Carl Sagan

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    Quote Originally Posted by ASTRO BOY View Post
    I need the skills of those into the maths of such known facts to invalidate this Vector gravity.
    Any takers?
    The arxiv version of the paper behind the paywall: https://arxiv.org/pdf/1511.07058.pdf

    Some points:
    - The composite photon theory doesn't work. So the composite graviton theory they use in their model will have the same issues that are so far, in the photon theory, got around by adding in arbitrary fixes. It doesn't look like they have used these arbitrary fixes (for example the composite photon theory adds in extra terms to the formulae for Bose Einstein statistics - here they just assume that these terms are small for both which I am not sure is fully explored).
    - It also creates a significant issue in that they predict a spin one graviton - I couldn't find how they dealt with the symmetry problems this generates.
    - The prediction of no black holes comes from their prediction of a variable speed of light. No such variation has been seen and it has been looked for. A lot. I couldn't find a discussion of the experimental evidence for this.
    - They link dark energy effects to matter currents. This is hard to reconcile with the current observations suggesting that in the recent, less dense, universe expansion rates have accelerated.

    I'm not a GR guru and don't fancy reviewing nearly 60 pages of maths so I'll leave it there. Hopefully someone who enjoys GR will dive into it more.

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