Cosmological Red Shift

Discussion in 'Astronomy, Exobiology, & Cosmology' started by The God, Apr 3, 2016.

  1. river

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    • Inarticulate dismissal suggests this is sterile denialism. Determine what you believe and why you believe it and why others should believe it, then tell us what you found out. Then you will be part of the conversation.
    Then pad you are a simple minded
     
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  3. Schneibster Registered Member

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    Maybe you should, you know, say why. And stuff.
     
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  5. expletives deleted Registered Senior Member

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    Schneibster:

    I did not allude to bicep2 because that involved a narrow and limited observational 'window' in both depth and angle on the sky------unlike the Planck and WMAP work.

    I think you mistook my meaning regarding the observational margin of errors involved; which may explain why you also seem to have missed my point about the mapping ambiguities which may arise if not strictly careful to avoid assuming confidence levels which may be more wishful thinking than scrupulous analysis and conclusions (eg, I think that everyone now agrees that the confidence levels claimed for that bicep2 analysis and conclusions was pretty high, yet totally unwarranted; so claiming high confidence levels and low margin of error levels does not automatically mean the conclusions and 'map' are actually scientifically valid. Are we agreed on that much healthy scientific skepticism at least?).

    So then, it's not so much the CMB signal data collection being "wrong" or "right" in themselves, it's more that the analysis and conclusions may not be as reflective of the actual deep space configurations and processes in time, distance, isotropy or an-isotropy terms; and so leaving open the likelihood that the interpretation of the data, as input to the WMAP composition, may not be correct given the great margin of error involved as I have been led to understand by the relevant literature. Again, and since you mentioned bicep2, the initial bicep2 'mapping', of even its quite small part of the sky, was also misinterpreted and hence produced a misleading 'map' for even that small part of the sky. I hope this fact confirms for you that it's a healthy scientific skepticism (not blanket denial) that I am questioning from?

    Which supports my healthy scientific skepticism when I see claims made, to the effect that, the 'map' has smaller margin of error than the variations in the data. It's obvious that, again, given the ambiguities which I already pointed to as likely due to the already admitted difficulties in being sure of what Planck is actually seeing (dust in local and intervening deeper space; and processes which may further polarize and disperse-reform any signal from CMB-radiating features, making it quite tricky to 'decipher' distance and angle and intensity information after the CMB radiation has traveled the very long distances from sources which such as WMAP purports to attribute background and variations to), that the need for a healthy scientific skepticism is very much indicated at this juncture. Much more work needs to be done, and less overconfident assumption, than currently informs the 'maps' and the CMB theory interpretations built into them.

    The whole point of my skeptical questions to you have gone to the issue of attributing redshift to expansion; as well as the effect such expansion theoretically has on the photon itself to produce the redshift attributable to "cosmological" space expansion and not local SR Doppler space motions. So I will leave that paragraph alone, and instead proceed to the next few paragraphs of your reply, which actually address my earlier distinction made between SR frames and GR frames considerations when it comes to separating the Doppler-Cosmological aspects of redshift components.

    I think that an, admittedly simplistic, yet still illustrative, analogy found in the mainstream literature on Universal Expansion may help us sort out what I mean and what you mean.

    Recall the "raisin bread expanding in the oven" scenario. It illustrates that while the space between raisins (read 'galaxies') is somehow 'increasing', the local space "takes the raisins with it"; such that the local space where the raisins are 'stuck' does NOT itself expand in the local frame.

    Now imagine that, while the bread is 'cosmologically' expanding as described, one inserts some probes to 'unstick' and move the raisins towards and or away from each other across the expanding bread dough, from old position to new position! This movement is real and not of 'cosmological' origin or cause!

    Now do you see the essential difference: between cosmological GR-like "changes in distances" due to space itself; and the SR-Doppler like "changes in position" in that local space due to real translational effects introduced by whatever means in addition to the cosmological aspect?

    The conflation by some, between the two components is what, is what introduces confusion in me and possibly in others. That is why I have been trying to elicit some common ground understanding on these two aspect before accepting explanations which may be conflating the two; and so affecting the discussion of all the related aspects on CMB and or redshift data and maps which may be constructed from conflated interpretations and conclusions due to inferences being drawn and confidence levels being claimed, which may not be as valid as they at first appear to anyone who does not display the healthy scientific skepticism when understanding and explaining things which may consistent in a mathematical theory but not consistent with the actual cosmos.

    Schneibster, I don't doubt your scholarship in the theory as you see it, but I am not at present in a position to see it the way you and some others have explained it. Mainly because my reading has also come across mainstream physicists and cosmologist who also see it as I do, not as you and some other learned members here do. Hence my continued confusion.

    Make no mistake please, I do agree with the contention by you and others that the two components (Doppler and Cosmological) of redshift cannot at present be discerned so as to attribute accordingly and proportionally. However I do not agree that the SR-Doppler "convenience" can be applied and the cosmological factor ignored IF the Big Bang and Expansion is as theory claims. If it is as theory claims, then there must be a cosmological redshift component and a cosmological mechanism for that photon being affected in flight between galaxies (in addition to the normal local space motions of SR-Doppler scenario).



    PS: I will address your last post to me above, after giving you time to read and digest this post. The postulation of local space or cosmological space both having 'flat' or 'minimal' so-called "curvature in current epoch is a separate aspect which I would prefer to discuss only after we have come to mutual agreement on the above discernment between SR-Doppler component and GR-type component of redshift as such (also leaving aside for the moment any answer to The God;'s question about what "mechanism" theory has or has not provided for each, but especially for the latter component effect on the photon to produce a redshifted photon above and beyond the local-SR-Doppler component).

    Thank you, sir, once again for your patient and learned approach to discussion of these difficult issues with a complete stranger. Very engaging; and most fruitful.
     
    Last edited: Apr 15, 2016
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  7. Schneibster Registered Member

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    Before we go on, expletives deleted, I have to tell you that I have had a completely novel (to me) paper come along and turn my head. You will understand why when you see it:

    http://arxiv.org/pdf/astro-ph/0310808v2.pdf

    I suggest you give it a read. It turns out that there are, in fact, different kinds of motion, and that galactic redshifts are caused by a kind we can never see because it doesn't happen within millions of light years of us. It's due to the cosmological constant term in the EFE, and is what astrophysicists and cosmologists are talking about when they say things like, "expansion of space." It is not describable in SRT. It's one of the terms in the EFE that's zero in GRT when SRT is exactly correct. It's very weak even compared to the gravity of galaxies within a few million light years of us; that gravity overwhelms it. But when the light years add up to hundreds of millions and billions, this effect adds up right along with it, whereas the gravity is falling off by the inverse square force.

    You will find my arguments rather altered by this, so I suggest you look it over before you read anything I say from now on. This was a "eureka moment" for me, and explains a number of things that I have been puzzling over for years.
     
  8. expletives deleted Registered Senior Member

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    Schneibster:


    Thank you, sir! I have a longstanding cached reference of that paper as a PDF file. It obviously formed part of my longstanding wide reading on many scientific matters, including cosmology, of course; else we wouldn't be having our present discussion, naturally; for which discussion I thank you regardless, since your patient, scholarly and gentlemanly approach to discussion with me has led to much reinforcement of knowledge and understanding in my own scientific information base (and, as I now find out from your own lips above, in yours also).

    Does this mean you now agree with my understanding of the matter in question? And that both Russ_Watters and his faithful and uncritical 'liker' paddoboy stand to be corrected by you in the near future after you have digested that further reading you referenced?

    Anyway, sir, it's been a pleasure, irrespective. I look forward to interacting and discussing with you in future whenever our paths and discussions should cross in this very nice, and helpful, scientific forum. Best wishes.
     
  9. The God Valued Senior Member

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    In some other thread you are insisting that spacetime is something like thing...whatever that means.

    I suggest you should read a paper by Geraint F Lewis, it is on the similar lines as that of this Arxiv paper...I will try to trace out and paste a link here...not able to sort as of now.

    It is heartening to note that you stormed this thread, brought in substantial discussions, almost everyone barring a few like me and Expletive Deleted, latched on to you, and now you have a change of heart. Good for you rather great for you but what about those who extended support to your earlier argument ? Will they alter their stand ?
     
  10. Schneibster Registered Member

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    OK. But I think you overestimate these supposed mapping ambiguities by far too much.

    I'm going to need to know exactly what ambiguities you are referring to. At least give some concrete examples. I'm not aware of any "great margin of error" that is systematically affecting everything we see, nor of any literature that alludes to it. In fact, what we can see seems to be constantly reducing the margin of error; Planck is still collecting data, and all of that data is consistent with (though very much more precise than) WMAP. You're making a blanket assertion about this despite your claim not to be engaging in blanket denial, and that's not sitting well with me.

    Let's keep in mind that we're discussing two different things: CMB and galactic redshifts. The problem with your statement is, they agree, overall; and where they don't we understand why; and finally, you've shown no actual reason to doubt either of them but some sort of unspecified "great margin of error" supposedly in "the literature" without providing links to or even descriptions of this supposed literature that supposedly supports these supposed "great margins of error." Can you see why I'm pretty skeptical of your claims?

    There isn't anything else to attribute redshift to. There's motion as we ordinarily understand it, in the second term of the EFE, and there's expansion of space in the third term, and that's all. Nobody's proposed adding any more terms to the left side of the EFE, because there are no observed effects that justify it.

    Now, expansion of space and motion as we ordinarily understand it are different things; and to expect one to behave exactly like the other is silly. But to expect both to show Doppler shifts is not; they both have to equal the stress-energy tensor on the right side of the EFE, so there is nothing to make Doppler shift due to expansion of the universe look any different from Doppler shift due to ordinary motion. There's no difference. The point of the paper that I linked is that they're different, but you will note if you read it carefully that it still says both of these phenomena produce Doppler shifts, it is only their causes that are different, and both are very well quantified by the EFE.

    And the problem I have with your "skepticism" is that it seems to go so far and no farther; you are not self-skeptical. Your arguments seem composed of nebulous objections based on supposed great margins of error supported by supposed papers that you can't even describe or link to, and I see that as the lead-in to a "god of the gaps" argument.

    There are two and only two things that can make redshift in the EFE: cosmological constant, which in our universe is small and positive, and motion as we ordinarily understand it. There is no third effect that has ever been required to explain everything we can see in local experiments, and there is no reason to believe that there is any additional effect "out there somewhere" when what we see "out there" is just the same as what we see here. It's not like there are spectral lines that don't correspond to any known element, after all.

    And redshift doesn't affect photons; it affects how an observer in a particular frame sees the frequencies of photons. The photons themselves have not changed. Neither expansion nor motion affects them; both expansion and motion affect the observer, not the photons. Conservation of energy, you see.
    [contd]
     
  11. Schneibster Registered Member

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    390
    [contd]

    They can't be separated. There is one and only one Doppler effect; it is the same whether the object is in motion as we normally understand it, or the space between it and us is expanding due to the cosmological term in GRT. The only way we can separate the components is in theory. We consider them to be different, but either way, the O-III line still has a primary peak of 500.7 nm and a secondary one at 495.9 nm, at the point where the lines were added, and it is still redshifted to a higher value if it is very far away.

    The difference between the two is only material when we are discussing very precise measures of distance and speed vs. redshift; using SRT redshift to calculate the recession velocities of distant galaxies is accurate to a distance so great that when the light left the site of emission there was nothing alive on Earth but single-celled animals and plants. And the fact you have to use GRT rather than SRT redshift doesn't make them "different." Redshift is redshift, and there's no characteristic by which these two supposedly different types can actually be differentiated.

    OK, so show where in the peer-reviewed literature any such effect has been proposed. It's a nice analogy but it doesn't seem to have any physical relevance without that. This still looks like a "god of the gaps" argument, the same basic argument the anti-evolutionists and the climate deniers use. Bring some evidence to support this view that there is something "unsticking" all the galaxies we see all over the sky from spacetime, and not only that but doing it to the CMB as well.

    Sure, but I don't see any difference in the Doppler shifts they each produce. Doppler shift is Doppler shift, whichever term of the EFE it comes from.

    It's not "conflation." It's simple physical reality: a redshift is a redshift, and some redshifts come from local movement and some come from the expansion of space. Show a way to differentiate between them or they're not "different."

    The problem is, they are consistent; otherwise the signatures of the elements in the spectra that allow us to detect the redshifts in the first place would be different!

    There's hydrogen out there, and no matter how far away it is, we can tell it's exactly the same hydrogen as here on Earth because it has exactly the same relation between its spectral lines as the hydrogen we have here, even though those lines are shifted. And if the theory of relativity were different there than it is here, those lines would have a different relationship. Not just a different redshift.

    So when I see you say things that claim that there is some sort of difference, I'm sorry but that's incorrect, and the very strong evidence shows it conclusively. There isn't any skepticism; this is data. And the relationships in that data are the same for data from a distant location as they are locally.

    And when I see you try to claim that there is some sort of "conflation" when in fact there is not, and I see you try to claim that this is "skepticism," I become very skeptical of your claims.

    I don't know why you think that there is any necessity for any cosmological redshift that applies to empty space. There isn't. The explanation for the redshift as the difference between distant frames and our local frame is the same either way: they're receding, and it doesn't matter a whit why. And the fact that we can't untangle the redshift due to motion from the redshift due to expansion doesn't mean they have to indicate anything but recession. Nor does it make any difference to the argument that they are different in different frames; it doesn't matter to that argument why the recession is occurring, it is and that's that. Nor does it make any difference to the Big Bang nor to expansion. Nor is any additional explanation or mechanism beyond the difference between the frames due to the recession required.

    I will confess to becoming irritated because you don't seem to be meeting your burden of proof. You're making some pretty wild claims about great margins of error without providing any sources to back it up and my answers are going to start getting shorter if you can't.
     
    Last edited: Apr 15, 2016
  12. Schneibster Registered Member

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    Nope. You're approaching a "god of the gaps" argument, however subtly you think you're doing so I can still smell it a mile away, and you're making claims of great margins of error without substantiating them, and these are huge red flags to me that tell me your arguments, when you finally have to present them, will not hold water. You have some research to do and some links to provide, and they'd better all be to peer-reviewed articles that have appeared in the scholarly literature or frankly I'm going to dismiss them out of hand.

    Nope. Russ is still right, and paddo is still right to support him, and there aren't any mysterious "gods of the gaps" in empty space introducing some sort of "extra redshift" and violating conservation of energy. The energy of a photon in the emitting frame need not be the same as the energy in the absorbing frame, and photons don't change in flight. There aren't any "great margins of error," and there isn't any evidence to support the claim there are because you haven't presented any. GRT doesn't require that photons change in any way in flight, and preserves the same relationship between frames that SRT does, and it doesn't matter whether the reason the frames are receding from one another is ordinary motion or expansion of the universe. The effects are identical in that respect.
     
  13. The God Valued Senior Member

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    Bad argument !
    Same effect does not mean, the causal process is same..
    Boiling is Boiling. You can boil the water by providing heat in many ways, does that mean that boiling of water has to be necessarily explained through one of them...whichever is more prevalent.
     
  14. paddoboy Valued Senior Member

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    Wrong: Geraint Lewis did not as far as I know have any paper on the reality of spacetime: From memory he gave an opinion about it and tashja supplied that here. And that is all it was concerned with...nothing else with regards to cosmological redshift, spacetime expansion or the GR theory in general.
    https://einstein.stanford.edu/content/relativity/q411.html
    https://www.quora.com/Is-spacetime-a-real-thing-or-just-a-mere-concept
    We've had all that before and you lost...sorry.

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    Now on to the funny part.
    Do I have a change of heart? No, certainly not.
    Does Schneibs? Not that I have seen.
    Schneibs gave a great explanation taking into account frames of references and it made complete sense to me, just as still does the explanation from our FoR, of light being stretched: I explained all that to expletive deleted, or was it you?

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    Let me go through it again.
    You could tell me that light bends when it passes a massive object: I would give you 9.5/10: nothing wrong with that.
    But another could say that light simply follows geodesics in curved spacetime: I give that 10/10. Understand?
    And yes I have read the paper and a very enlightening paper it is to.
    But it does not invalidate one iota the simple facts that I put in question form to you and expletive deleted. Both of you decided not to answer, although they were designed to gauge where you were coming from: The confusion in expletive's posts still trouble me somewhat, although I'm pleased he has taken my advice and started to use paragraphs.

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    Your stand though is obvious.
    Let's look at those questions again and I'll answer them for you....
    [1]Do you believe we see cosmological redshift?
    Yes
    [2]Do you accept the universe/spacetime is expanding?
    Yes
    [3]Do you accept standard accepted cosmology?
    Yes
    [4]Do you have problems with GR?
    No, it stands as unchallenged at this time for our model of gravity

    The paper by Tamara M. Davis and Charles H. Lineweaver do not challenge any of those aspects of cosmology. They still stand as unchallenged by academia and mainstream in general...that's the crux of the debate and that's what matters.
     
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  15. paddoboy Valued Senior Member

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    Can you spray that again?
    That is even more confusing and irrelevant then expletive deleted posts.
     
  16. paddoboy Valued Senior Member

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    Hmmmmm...There are quite afew posts where you have expressed your displeasure at me answering your posts and straightening you out.
    You begged me, you beseeched me to stay out of your threads.
    I now find your mention of me as rather strange, don't you think so?
    I mean are my questions just too difficult?
    Is to answer them truthfully to possibly expose some other hidden agenda?
    I don't know...its really strange though.
     
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  17. The God Valued Senior Member

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    What is so confusing about that ?

    He says that since the effect is same and hence cosmological redshift must be treated as doppler redshift...this is bad.

    for example I can kill a dog by poisoning or by exposing to radiation or by shooting or even by slicing...the end result of all the processes is same, but they are not same.
     
  18. The God Valued Senior Member

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    Your memory is ageing, paddoboy..lets see what all your new friend Schneibster alters in his mind.


     
  19. origin Trump is the best argument against a democracy. Valued Senior Member

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    Does this help?

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    Oops! I thought this was about cosmetological red shift.

    Never mind....
     
  20. paddoboy Valued Senior Member

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    Well, at least I do not ignore pertinent issues and questions when put to me.
    As I said anyway, the reality or otherwise of spacetime is debatable as I have shown you.
    On that particular issue I see Geraint as wrong. But you seem to have forgotten the other many E-Mail replies that he has given among many other professionals that have all rebuked some of you other nonsense.
    You continually forget about all that.
    And yet even with the paper to support you, you still refused to answer the relevant question.

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    And finally, The paper by Tamara M. Davis and Charles H. Lineweaver do not challenge any of those aspects of cosmology. They still stand as unchallenged by academia and mainstream in general...that's the crux of the debate and that's what matters.
     
  21. paddoboy Valued Senior Member

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    The paper you raised by Geraint Lewis [and others] also said the following......
    "The key is to make it clear that cosmological redshift is not, as is often implied, a gradual process caused by the stretching of the space a photon is travelling through. Rather cosmological redshift is caused by the photon being observed in a different frame to that which it is emitted. In this way it is not as dissimilar to a Doppler shift as is often implied".
    Are you understanding yet?

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    In other words just as per the analogy with "bending light" that I gave you, neither the above nor the claim of expanding spacetime is wrong:
    But obviously that will be an issue that you will continue to avoid.
    Schneibs was certainly spot on with his remark re your's and expletive deleted posts re "God of the gaps"

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    “People think that epilepsy is divine simply because they don't have any idea what causes epilepsy. But I believe that someday we will understand what causes epilepsy, and at that moment, we will cease to believe that it's divine. And so it is with everything in the universe”
    Hippocrates

    “No one infers a god from the simple, from the known, from what is understood, but from the complex, from the unknown, and incomprehensible. Our ignorance is God; what we know is science.”
    Robert G. Ingersoll,
     
    Last edited: Apr 15, 2016
  22. paddoboy Valued Senior Member

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    I must correct myself somewhat, you did answer the questions asked in 208, although as I replied in 223, your answers were more avoidance and cop outs.
     
  23. expletives deleted Registered Senior Member

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    Schneibster:


    How is it a "god of the gap" argument to question your claims which are not in agreement with my understanding reading the actual theory itself? It is honest arguments prompted by healthy scientific skepticism; especially as I am an atheist who does not engage in "god of the gaps" tactics in scientific (or any) discussions.

    That healthy scientific skepticism is supported by mainstream admission and discussion of the very same margin of error and other analysis and mapping procedures problems; the nature and extent of which are clearly outlined by the following example noted in this item in Wikipedia-
    As you can see, I was not imagining or denying anything; or using "god of the gaps" arguments. I was just being cognizant of the possibility of analytical artifacts which become possible in any analysis techniques, be it accepted standard or non-standard techniques. It is reasonable to have regard to this possibility when such significant margin of error plus tiny variations are involved in analyzing, interpreting and mapping CMB data and perceived features which may not be as assumed in analysis of confidence levels given to the work at any stage. So please sir, do not again make accusations against me of the "god of the gaps" kind, as I would not engage in such unscientific stratagems. Ever. Thank you.

    Leaving aside your attempted "god of the gaps" tactic to dismiss my healthy skeptical arguments in order not to address them seriously, I will proceed to the obvious sticking point which I have identified between our respective understanding as to what is actually involved when speaking of the "frame" aspect.

    I will attempt to highlight further the distinction which is crucial to be mutually understood between us if we are to arrive at some common ground, as follows.

    Here is an illustrative scenario: Two similarly massed galaxies separated by billions of Light Years.

    Their respective gravitational parameters, and all other local parameters, are in every way similar as to their GR FRAMES and SR FRAMES states. A photon from each to the other would be similarly received at their respective localities without any distinction between the two photons wavelength and frequency. In non-expanding universe, the only factor determining what those wavelengths/frequencies would be upon receipt at either end (by receivers placed in identical positions with respective to their identical gravity wells), would be their normal motional relativity through normal space, as per SR-Doppler principles. Agreed?

    Now we add a cosmological expansion aspect which purports to not produce actual motion locally, as per theory explained and agreed in your own recent reference; such that the only 'recession' inferred is an unidentified mathematical 'similar-to-Doppler' concept of 'motion equivalence' not due to SR-Doppler principles as such, but which is anyway 'lumped in' with the SR-Doppler term in the equations and analysis and interpretations which do not attempt to discern between the two types of values' or their causes. It certainly does not take into account the fact that the local motional relativity between the photon and the receiver is identical in each galaxy local frame irrespective of non-expanding or expanding scenario, because once the photons arrive at their destinations they are both in the same local frame as the receiver, and no actual cosmological expansion aspects apply at reception. So the logical conclusion is that any redshifting component in addition to what would have applied in non-expanding scenario must have been effected IN TRANSIT. There is no other consistent view IF the expansion theory is correct and expansion also affects perceived shift total values.

    Do you see where the problem arises? The lumping-in together of the SR-Doppler motional value related redshift component, with the Non-SR-Doppler non-motional value related redshift component, is mathematically convenient and consistent if one merely wants the total redshift value, but it does nothing to distinguish between the two components or explain the cosmological mechanism for the cosmological component

    The question is not denying that frames CAN be different, but that IF the SR FRAME and GR FRAME locally are IDENTICAL at both ends as in this illustrative scenario, then what is it that causes the total shift and not just the SR-doppler only shift which would be identical in both expanding or non-expanding space-time scenarios?

    If I have explained badly then it's my fault. But I can not for the life of me understand why this obvious aspect and distinction is not clear to someone who knows what frames are. Knowing what frames are, appears not to guarantee knowing which frame types are involved at particular stages and how not to conflate them. This seems to be the sticking point between us. So if you still haven't understood what I have been trying to point out that is possibly causing the confusion, then perhaps we should leave our exchange there and agree to disagree as scholars and gentlemen. Thank you for the discussion, Schneibster; it has been very useful and interesting, sir.
     
    Last edited: Apr 16, 2016

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