What would it take to prove Albert Einstein Wrong?

Discussion in 'Physics & Math' started by Quantum Quack, Jul 23, 2019.

  1. Schmelzer Valued Senior Member

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    This is not the point. There is no doubt that GR without dark matter (or any other modification) is falsified.

    GR together with cold dark matter is, instead, a sufficiently simple model, and it is not yet falsified (even if it has some problems, they seem yet insufficient to falsify it).
     
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  3. Quantum Quack Life's a tease... Valued Senior Member

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    Have they actually found cold dark matter? Or is it still purely hypothetical?
     
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  5. Quantum Quack Life's a tease... Valued Senior Member

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    Why don't they simply call it Dark gravity and kill two birds with one stone? (1/2 serious)
     
    Last edited: Aug 4, 2019
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  7. James R Just this guy, you know? Staff Member

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    No. It's you making the claim that general relativity is wrong. You have yet to make any attempt to support that claim, to my knowledge.

    I didn't miss it. Nothing in that earlier post supports your claim that general relativity is wrong.
     
  8. Quantum Quack Life's a tease... Valued Senior Member

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    So how do you interpret the comment by NASA:
    "You would be forced to conclude that either Earth had more mass than you had supposed and hence a stronger gravitational pull, or that the theory you had used to make the calculation was in error"
     
  9. Schmelzer Valued Senior Member

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    All scientific theories are hypothetical.

    Cold dark matter in its ideal form (that means, real dark matter, which is not interacting with the usual matter at all) can be found only in the way we already have found it - by observing the gravitational field it creates. What scientists are looking for are other things - some forms of matter which interact with usual matter in a very weak way. Something similar to neutrinos, or some other neutron-like particles which would not have electric or weak charges but would somehow interact via the strong charge with a nucleon. Such "almost dark" matter has not been found. All the "dark matter" search projects I know of only look for variants of such "almost dark" matter.

    Because they are scientists, that means, they don't play empty word games. ("Dark energy" is, in fact, nothing but an unfortunate word game. If one would have consistently named it "Einstein's cosmological constant", there would have been no problem with it in popular cosmology.)

    GR without dark matter is falsified. To solve this problem, one can add dark matter to GR. But one can also modify GR or use some alternative theory of gravity. This is imaginable too.
     
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  10. James R Just this guy, you know? Staff Member

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    In an earlier post, I already told you that it is always possible that current theories are wrong in one way or another. The quote here just says the obvious: if you have a physical system that doesn't behave the way your theory predicts it should, there are two obvious possibilities: (1) the data/assumptions/measurements about the system that you're feeding into the theory are incorrect, or (2) the theory that you're using to analyse/interpret the data, or to predict other features of the system, is incorrect.

    In the case of dark matter, we have a number of observations that strongly suggest "missing" mass. So, following the above schema, here are some possible solutions:

    1. There's something wrong with our observations - maybe we've somehow "missed" recording visible mass.
    2. There's something wrong with our observations, in that we haven't detected mass that is actually there in some form but "invisible" to our current detection methods.
    3. The observations are correct, but our best current theories are wrong in that they require "too much" mass, for some reason that we don't yet understand.

    Three possible research programs suggest themselves, in consequence:

    1. We should think about how we could possibly be "missing" visible mass in our detectors.
    2. We should think about possible kinds of matter that our current detectors are insensitive to, and try to build new detectors that are sensitive to those "new" kinds of matter.
    3. We should consider possible modifications or replacements of current theories, such as might be able to account for the observations we already have but without the need to introduce new kinds of mass that are hitherto undetected.

    All three of these research programs have been or are being pursued. At this stage, most physicists are skeptical about possible solution number 1. Out of options 2 and 3, the most promising one at this stage looks like option 2 - that there is a hitherto unnoticed form of "dark matter" that adds "extra" mass, thus accounting for the observed anomalies. Option 3 is also in play, but to my knowledge nobody has yet produced a viable alternative theory of gravity (or whatever) that would adequately account for the observational data we have, without the need for dark matter.

    You, QQ, have told me that you believe that solution 3 is the correct one. You haven't said why you think it's more likely to be correct than 2, and you haven't given any good reason why you think 2 can be ruled out.
     
    Last edited: Aug 4, 2019
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  11. paddoboy Valued Senior Member

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    Unadulterated bullshit.
    A scientific theory is the best it gets, and is an account of what we observe and explanation for our experiments, that are continually validated and verified within their zones of applicability.
    As scientific theories become further established and continue to pass tests and scrutiny, they grow more certain in their field. Examples are GR, SR, the BB, and evolution, with of course evolution.
    When your own hypothetical passes scrutiny and professional peer review, it may reach that top echelon of scientific theory.
     
  12. Quantum Quack Life's a tease... Valued Senior Member

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    Thank you for your post. It clarifies the current position very well IMO.
    Fortunately or unfortunately depending on your perspective, I have no preconceptions that have to be removed when assessing this problem objectively. I have no allegiance to any particular conceptualization or ideas that may prohibit aggressive exploration of a solution.
    As to solution #2, currently it is unfalsifiable due to the dark matter remaining at this stage at least a purely hypothetical object.
    If I did indeed have a way to solve this issue (not a solution per see) I would not be posting it here as that would be off topic and ultimately force this thread into early closure or moved to the alt theories section. Given the animosity that has been historically displayed towards me at this fora, I wouldn't be all that interested in pursuing it any how.

    The topic of discussion is not about alternatives but about how a theory like GR can be proven wrong.
    The need for dark matter appears to be one of those ways.
     
  13. Quantum Quack Life's a tease... Valued Senior Member

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    it can not be ruled out but it still deeply suggests that GR fails to be universally inclusive.
    To me, the creative generation of a virtual object simply to maintain a theories veracity is a strategy/method of last resort. To use an imaginary object to fill in the gaps is to me something only used in preliminary theoretical work and again as a last resort. Therefore, if I was qualified to do so, which I am not, I would be more inclined to reassess all the theoretics that led to such a need, as a primary consideration before using an imaginary gap filler.
    I would be looking at all the premises that are being utilized.
    I would be reassessing all the core principles, at the underpinning philosophy, logic and rational, and so on before I would allow an imaginary object to dominate the solution, because once you install a virtual solution in the minds of people it is incredibly hard to change it later.
    That is why I prefer #3.
     
  14. paddoboy Valued Senior Member

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    27,543
    No theory is universally inclusive and I add I don't believe any theory can be universally inclusive. We are only aware of and could anyway only possibly include the observable universe. That in itself is also beyond us at this time. Also obviously we are unable to apply our theories to all possibles situations.
    The truth or reality of the universe, is not the goal of science. Science models to explain what we observe and the results of experiments. If they happen to reveal any truth or reality, then all well and good, but again, that is not the object or goal.
     
  15. James R Just this guy, you know? Staff Member

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    QQ:

    Scientists working on this stuff similarly have no such allegiances.

    Nonsense.

    Many specific possible candidates have been put forward as the hypothesised dark matter. Maybe dark matter consists of large, dead star remnants, for example. I believe that particular hypothesis is not only falsifiable but actually falsified (or at least considered very unlikely). Maybe dark matter is mostly or wholely made up of neutrinos. That idea is similarly falsifiable in many different ways. Maybe dark matter consists of as-yet-undiscovered supersymmetric matter. That hypothesis, too, is falsifiable.

    That something is currently hypothetical does not mean it is automatically unfalsifiable, in Popper's terms. The idea that the sun is powered by nuclear fusion was once an unverified hypothesis. That doesn't mean the idea is unfalsifiable.

    Then we agree. GR might be proved wrong if some other theory turns out to explain the observations without the need for dark matter.

    I was under the impression, however, that you thought the dark matter problem had already falsified GR. If you agree with me that it hasn't, then there's not much to argue about here.

    Not at all. If dark matter turns out to exist in the form of some kind of particles with ordinary mass, then GR will require no modification at all to accommodate the new dark matter.

    The term "dark matter" is not a virtual object. It is just the name given to that knowledge gap you mention. It's a place holder, until we work out what's going on.

    You refer to dark matter as an "imaginary object", but you don't know whether there's an object involved or not. If there is, then it won't be imaginary, it will be a real physical thing, as real as electrons or atoms.

    As for reassessing the theoretics, that's already being done by a large number of theorists, in parallel with the experimentalists and astronomers who are searching for those non-imaginary objects that might be out there.

    The "gap" you mention is not imaginary, as I think we both agree. I don't know why you want to throw out lots of possible ways that might fill that gap right from the start, rather than leaving all alternatives open until we can rule one or more of them out. That just reeks of an ideological bias, which is antithetical to science.
     
  16. Quantum Quack Life's a tease... Valued Senior Member

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    Just a quicky...
    Does GR predict the existence of dark matter?
    Does it make predictions about gravity with out dark matter?
    What does your answer suggest about GR?
     
  17. paddoboy Valued Senior Member

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    27,543
    https://theconversation.com/how-we-...t-means-for-dark-energy-and-dark-matter-98481

    extract:
    Our working theory for gravity comes from Albert Einstein’s general theory of relativity, which states that gravity is a consequence of massive objects warping the very fabric of spacetime. Scientists have validated the theory with great precision in our solar system, but we haven’t been able to do the same on larger distances – until now.

    Our new study, published in Science, shows that general relativity also holds true on the scale of entire galaxies. The findings strengthen the popular view in cosmology that 95% of the universe is made up of invisible substances dubbed dark matter and dark energy – ruling out several competing theories.
     
  18. Quantum Quack Life's a tease... Valued Senior Member

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    All well and good...but....
    it fails to address the questions.
    Does GR predict the existence of dark matter?
    Does it make predictions about gravity with out dark matter?
    What does your answer suggest about GR?

    Given that Einstein passed away in 1955 and dark matter was first proposed in 1884 by Lord Kelvin, I am curious as to whether Einstein included the prediction of dark matter in GR... as he would have no doubt been aware of the dark matter hypothesis of the time.
     
    Last edited: Aug 4, 2019
  19. CptBork Valued Senior Member

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    Yes, GR predicts the existence of dark matter. It's predicted to exist based on the gravitational patterns observed, just like other astronomical bodies have been predicted in the past from their gravitational effects before direct discovery.

    Yes, it makes predictions about situations with any kind of matter you wish to postulate, as long as you can write down its stress-energy tensor.

    It suggests that GR predicts stuff and can be used to model what we currently observe. The need for dark matter in GR to explain certain observations does not disprove anything unless you can prove that dark matter doesn't exist, which of course you personally cannot.
     
  20. Quantum Quack Life's a tease... Valued Senior Member

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    ok...
    Thanks for that...and thanks for your patience...
     
  21. James R Just this guy, you know? Staff Member

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    No. Nor does it predict the existence of normal matter, like electrons and protons.

    Yes. The theory is agnostic about the form that mass takes.

    It suggests that GR can happily deal with lots of different forms of matter and energy.
    ===

    Edit to add: CptBork's answer is equally valid.
     
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  22. CptBork Valued Senior Member

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    It's my pleasure, but I hope you won't simply disregard my answers next time you want to assert something, without addressing what I wrote first. Dark matter is not a fudge factor, it's an unconfirmed prediction of the theory. If you want to remain skeptical based on the fact that this prediction hasn't been confirmed by any other means besides astronomical observations, that's totally your call. However, I don't see why you're not satisfied with rejecting GR (in its present state) on the grounds that it can't describe atomic-level phenomena, why is that not a sufficient reason for you?
     
  23. Quantum Quack Life's a tease... Valued Senior Member

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    Now that is a brilliant way of putting it...!!
    Thanks...
     

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