Talk:Redshift/Archive 8

Prediction vs. description

Now, this one is tricky. User:Harald has made the change appealing to NPOV, but I think it's probably more an issue of accuracy. Is it accurate to state that current models of cosmology and the FLRW metric predict the Hubble Law? In the sense of an exposition on the subject of the Hubble Law, absolutely. In the sense of the historicity of the subject, absolutely not. I was assuming that the article had a tone of the former and not the latter. What do others think? Is it misleading to claim that these ideas predict the Hubble Law when the word "predict" can mean two different things? Is there a better word that is stronger than "describe" that can convey the meaning we're trying to get at here? --ScienceApologist 19:45, 3 May 2006 (UTC)

I pressed the Send button before choosing the motiovation; yes I agree it's a matter of accuracy, but neverheless in a possibly propagandistic way (its use may well stem from propaganda for theories, for "predict" sounds great). Thus I had a similar tricky hesitation about how to phrase the motivation. Of course, if it has been shown that the Hubble law was a non-obvious outcome of the current model when it was drafted, then it's an achievement for which "predict" may be appropriate (although still inaccurate). And I also agree that "describe" is a bit weak; "correctly describe" is maybe better, but a bit long. Harald88 20:01, 3 May 2006 (UTC)

The obviousness of the prediction/description is not relevant to our discussion as that isn't part of what makes something predictive. I think the real issue is one of causality -- it definitely did not happen that someone predicted Hubble's observations beforehand. (No one had the foresight to look at the normalized time derivative of the scale factor and ask what might happen if a photon signal experienced the time dilation associated with this.) But this doesn't mean squat in the narrative of science which puts effect before cause all the time (perhaps because scientists are such gleeful revisionists as the scientific method allows one so easily to correct past errors). In any case, we need a word to describe this. How about "prescription" or "dediction"? (Upon writing this, I really wish the latter was a word. Too bad neologisms are frowned upon, eh?) --ScienceApologist 20:11, 3 May 2006 (UTC)

See also

This section did not contain content relating to Redshift as a topic, so it was moved to Talk:Redshift/See Also Dispute June 2006 in an effort to refactor this talk page and improve its readability. Please move all talk about See Also policies and the creation of See Also lists there. Flying Jazz 20:43, 7 June 2006 (UTC)

Quantum Gravity

The following content is part of the Redshift article:

"The theory of general relativity, on which the Big Bang theory is based, breaks down at this point. It is believed that a yet unknown theory of quantum gravity would take over before the density becomes infinite." (Last paragraph of the section Extragalactic observations)

I would be grateful for an explanation of (a) What relevence this sentence has to redshift (posted by Iantresman 20:58, 7 June 2006 (UTC), refactored by Flying Jazz)

This is z = infinity. --ScienceApologist 21:37, 7 June 2006 (UTC)

Are you sure? An infinite density with no expansion would have an infinite redshift? Or do you mean that in the first infinitesimal moment of expansion there would be an infinite redshift? Ian seems to have a valid point that this paragraph strays from the topic of redshift. The article would serve the reader better if it mentioned redshift at or near the end of the "extragalactic observations" section to drive the point home to the reader that the most commonly held opinions about the big bang are based on extragalactic redshift observations. Flying Jazz 22:55, 7 June 2006 (UTC)

An infinite density with no expansion would have an infinite redshift? --> Interestingly, yes, though that's not the sense in which the singularity serves as z = infinity.

The article would serve the reader better if it mentioned redshift at or near the end of the "extragalactic observations" section to drive the point home to the reader that the most commonly held opinions about the big bang are based on extragalactic redshift observations. --> Seems like a reasonable suggestion.

--ScienceApologist 12:17, 8 June 2006 (UTC)

Redshift Quantization

[I would be grateful for an explanation of] (b) Why a link to Redshift quantisation, is not "content relating to Redshift as a topic". --Iantresman 20:58, 7 June 2006 (UTC) (refactored by Flying Jazz)

Sure. A link to Redshift Quantization is content relating to redshift as a topic. Debate about the policies of See Also lists is what I refactored. If there is input from other editors, I would support including a link to Redshift Quantization if it were put in the right place in the bulk of the article. For example, changing the sentence:

"Alternative hypotheses (for example, tired light and intrinsic redshift suggestions from nonstandard cosmologies) are not generally considered plausible."

to

"Alternative hypotheses are not generally considered plausible. These hypotheses include: tired light, redshift quantization, and intrinsic redshift suggestions from nonstandard cosmologies." Flying Jazz 21:14, 7 June 2006 (UTC)

Redshift quantization should not be included because it cannot be properly contextualized in an article due to an unwillingness to overload the article with research about redshift distortions. --ScienceApologist 22:01, 7 June 2006 (UTC)

ScienceApoligist, is Redshift quantization nothing more than one of many types of redshift distortions? If so, then why does the Redshift quantization article not mention distortions once and mentions Arp, intrinsic redshifts, etc multiple times? Flying Jazz 22:39, 7 June 2006 (UTC)

I sometimes feel that we're all playing Rock, Paper, Scissors, where one of us will only play by the rules, the other will only play if we don't metion the rules, and the has one set a summary set of rules for themselves, but requires them in triplicate for everyone else. --Iantresman 22:11, 7 June 2006 (UTC)

Which begs the question, why does Redshift quantization require different contextualization to tired light and intrinsic redshift? --Iantresman 22:14, 7 June 2006 (UTC)

Ian, you are proposing the addition of a link to Redshift quantization to this article. If you believe it should have the same contextualization as tired light and intrinsic redshift, then I might agree with you if you explain why and other editors understand your reasoning. If you believe it should have a different contextualiation then please explain your reasoning. Flying Jazz 22:39, 7 June 2006 (UTC)

The proposed sentence already provides satisfactory contextualisation for tired light, and intrinsic redshifts, with additional context available by clicking on the links themselves; it seems that this should cover Redshift quantization too. --Iantresman 23:11, 7 June 2006 (UTC)

Unfortunately it doesen't because redshift quantization isn't contextualized by a nonstandard paradigm per se but is contextualized by redshift distortion observations. Tired light and intrinsic redshifts are ideas meant to explain away the Hubble flow. Quantized redshifts are actually referring to (supposed) observations. --ScienceApologist 01:40, 8 June 2006 (UTC)

In which case, let's move Redshift quantization to a more appropriate place, a couple of sentences earlier, eg:

When the redshift of various absorption and emission lines from a single astronomical object is measured, z is found to be remarkably constant. (See Is the fine structure constant really constant?, but see also Redshift quantization)"

--Iantresman 08:46, 8 June 2006 (UTC)

SA: your point seems to be that if redshift quantization were observed, an attempt would be made to explain it according to redshift distortion phenomena like those reported in Hamilton's paper. Hamiliton seems to say that distortions (like Fingers of God) are due to the peculiar velocities of galaxies in space relative to our velocity, and they are related to various astrophysical parameters thought to be constants. From this, you are arguing that since redshift distortions are not discussed in the article, quantization has no context in the article so it shouldn't be present. I disagree with your reasoning because even though the words "redshift distortion" don't appear in the article, the core of what Hamilton is really talking about does appear in the current article: namely the Doppler effect and the expansion of space.

Ian: your point in your last post seems to be that if redshift quantization were observed, an attempt would be made to explain it by consideration that various astrophysical parameters are actually not constants. From this, you are arguing that the location in the article where a constant is discussed provides a context for the inclusion of quantization. I can't agree with that because the location you're arguing for now is about a single object, and quantization, were it present, would involve a survey of every distant object in the sky.

I think both of you have a point, but you are thinking too much about what would happen if this were observed and thinking too little about the reality that it is a discredited observation. My point is that even though quantized redshifts refer to discredited observations while intrinsic redshift and tired light refer to discredited theory, they have the important trait in common of having been discredited, so they should all be lumped together in that context. My main concern is that too many discredited things will appear in the article. Feel free to counter my disagreements, and hopefully other editors will also comment. Flying Jazz 11:40, 8 June 2006 (UTC)

I can find no references that suggest that Redshift quantizations are discredited. I find papers that support them, and one paper concluding "no evidence for a periodicity"[1], which in itself has been criticised[2]. If any of us editors knew for sure, we'd get a paper published without any problems.

So, another suggested tweak:

"Alternative hypotheses and observations are not generally considered plausible. These include: tired light, redshift quantization, and intrinsic redshift suggestions from nonstandard cosmologies."

--Iantresman 12:17, 8 June 2006 (UTC)

Ian, I think you're right that my word "discredited" may have been too strong to use for conclusions that were later found to be implausible when a larger set of data were used. I wouldn't call redshift quantization an "alternative observation," but I might call it a rejected conclusion from a data set that was later found to be too small. Flying Jazz 14:24, 8 June 2006 (UTC)

My point is that even though quantized redshifts refer to discredited observations while intrinsic redshift and tired light refer to discredited theory, they have the important trait in common of having been discredited, so they should all be lumped together in that context. My main concern is that too many discredited things will appear in the article. Feel free to counter my disagreements, and hopefully other editors will also comment. --> Referring to these ideas as "discredited" makes perfect sense to me, but Ian has some difficulty reading into the criticisms of redshift quantization as actually discrediting the observations. I think the reason for this is because of the mechanisms Hamilton points out (which are, by the way, a bit more involved than simple peculiar velocities: they really deal with the statisical relationships in a uniform field with imposed noise due to structure).

What I see as the issue is that to explain exactly why redshift quantization is discredited, we'll have to make some detailed analysis of redshift distortions. In particular, any redshift quantization would appear as a trace in correlation matrices and there are predicted quantizations due to, for example, the 1 degree anisotropy observed in the CMB. This seems utterly tangential to the discussion of redshift. It might be nice to discuss in the redshift quantization article itself, but I'm inclined to agree with you that as we continue to list off discredited ideas we begin to write an article that isn't useful to the reader.

--ScienceApologist 12:24, 8 June 2006 (UTC)

SA, the issue is what gets written in the redshift article, not Ian's difficulties (or yours or mine) in interpreting the literature. I agree that an in-depth discussion of redshift quantization is not appropriate in the redshift article, but nobody is proposing this. Is your only objection to Ian's suggested tweak that it increases the list of implausible items from two to three? My thinking is that there are an infinite number of implausible things in the world, so we have to be very careful in picking and choosing what gets into the article. However, many readers really are interested in controversies and in rejected alternatives when they read an encyclopedia article about certain types of science. Redshift quantization seems like a different flavor of implausibility (an implausible conclusion from an observational dataset that was too small?) from intrinsic redshifts (an implausible grab-bag of "something-else" theory?) and tired light (an implausible specific theory). I hope you can begin with Ian's suggested tweak and try your hand once again at "writing for the enemy" to formulate a brief way that we can include all three of these implausible things in one or two sentences. Flying Jazz 14:24, 8 June 2006 (UTC)

Actually I'm proposing that there are two issues: one)redshift quantization as a subject is too niche to warrant inclusion (it was excluded by the LaPella criterion) and two)redshift quantization is only appropriately contextualized by a discussion of redshift distortions. What I'm saying is that if we are to include redshift quantization in the article, I think it only fair to mention the mainstream research in that area which is the research projects involving redshift distortions. However, it seems to me to be too narrow a project to warrant inclusion in this encyclopedia.

As for lumping redshift quantizations with tired light and intrinsic redshifts I must protest. The context for discussing the latter two items is that they are alternative (and not considered) suggestions about the Hubble Flow. Redshift quantization is a supposed observation (not an alternative one) that may be part explainable by geometrical and large-scale structure arguments relating to peculiar velocities. That they were considered by nonstandard proponents to be uniquely interesting is a perspective afforded the nonstandard proponent, but it is an extreme minority view. It just happens that these people decided to jump on this particular idea as a support for their alternatives -- it's really too many levels of specificity removed for me to envision how to include the subject fairly in the article without an entire paragraph and a discomforting violation of the undue weight ideals of NPOV.

--ScienceApologist 15:57, 8 June 2006 (UTC)

• I thought that the LaPella criterion showed that Redshift quantisation was of similar notability to (a) intrinsic redshifts (b) the Wolf effect, and (c) 10 times more notable than the Transverse redshift[3]?
• Quote: "When the redshift of various absorption and emission lines from a single astronomical object is measured, z is found to be remarkably constant. (See Is the fine structure constant really constant?)". In this sentence mentioned earlier, I note a reference to something called the "Fine Structure Constant". It's not mentioned anywhere else in the article. It has no explanation. It has no context. (And the article on the Fine Structure Constant doesn't mention Redshift). Even "Fine structure" is mentioned nowhere else, let alone its "constant". Am I missing something about context which you want to apply to Redshift quantization, that doesn't seem to apply to Fine structure? --Iantresman 17:46, 8 June 2006 (UTC)

You thought wrong about (a) and (b). Point (c) is irrelevant as far as I'm concerned. --ScienceApologist 17:53, 8 June 2006 (UTC)

So how do we assess whether Redshift quantization is about equal in notability to (a) intrinsic redshifts (b) the Wolf effect, and (c) 10 times more notable than the Transverse redshift? --Iantresman 18:01, 8 June 2006 (UTC)

For both of you: To me, arguments about notability are important in biographical articles or articles about popular culture, but they are almost always a mistake in science articles. In science, I think notability is useful only when comparing apples to apples in terminology discussions. For instance, should the term "intrinsic redshift," "non-cosmological redshift," or "untrivial redshift" be used in the article? Those are all terms for redshifts that aren't explained by the three frameshifting mechanisms, and they all mean roughly the same thing, but we want an article that uses the most popular term, so notability is important. It's good that we picked the most notable of the three and have a link to "intrinsic redshift" and no link to "untrivial" or "non-cosmological." Notability is always a matter of opinion in the discussion of whether something is included or not, so SA's "issue one," the "LaPella criterion," and Ian's (a), (b), and (c) won't help us.

For SA: Your issue two is a different matter. On the one hand, you write "redshift quantization is only appropriately contextualized by a discussion of redshift distortions" and you protest the inclusion of redshift quantization in the redshift article on the grounds that quantization observations have been a subset of mainstream research that alternative-cosmology folks have been attracted to. But then I take a look at the Redshift quantization article, where the history indicates that you have made dozens of edits of all types, and redshift distortions aren't mentioned once! You can argue that redshift quantization must be contextualized by a discussion of mainstream research about distortions, but when you've written chunks of the redshift quantization article and haven't mentioned mainstream research about distortions, why should anyone take your argument seriously?

Also, if quantization is really a subset of mainstram research in distortions, why isn't it mentioned once in Hamilton's paper that you provided to us? I think you want it both ways, and I don't think you're being honest about your motives. Why do you really want redshift quantization kept out of this article? I might agree with you if I understood the real reason instead of reasons based on policy and self-contradiction. I hope you reread Ian's suggested tweak and change the language to reflect the reality of the situation in 1-2 sentences and I hope you edit the redshift quantization article to make it look the way you think it should. Flying Jazz 19:47, 9 June 2006 (UTC)

• Another solution, would be to have a paragraph on "Redshift criticisms" (but with a more appropriate heading), which is conspicuous by its absence. While subjects like Intrinsic redshift, Tired light, Redshift quantization, are perhaps in themselves minority subjects, together, they make up a more significant "criticism" of the subject.
• There is no doubt that there are criticism to do with redshift; these are not necessarily put forward by non-standard cosmology supporters, it's just that the criticisms might imply this.
• Such a paragraph would also mention the accepted explanation for high-redshift and anomalous redshift measurements, and not only mention these minority views, but give ScienceApologist the opportunity to explain the standard line? --Iantresman 21:00, 9 June 2006 (UTC)

An awful idea in my opinion. A section like that would turn an encyclopedia article about a scientific observation into an unencyclopedic bulletin board of points and counterpoints that almost nobody in the field cares about or bothers to learn because the information is useless and silly. Still, even though this is a really bad suggestion, I appreciate you making it here and making your advocacy clear. Flying Jazz 00:39, 10 June 2006 (UTC)

You can argue that redshift quantization must be contextualized by a discussion of mainstream research about distortions, but when you've written chunks of the redshift quantization article and haven't mentioned mainstream research about distortions, why should anyone take your argument seriously? --> I don't pretend to understand why the anti-bangers like redshift quantization so much, but they do. I haven't put any context in that article because, frankly, I haven't had the time to do so. It's really a delicate matter because the quantization claims are an obscure sidenote to the real points about redshift distortions. Right now we have more pressing issues in the cosmology articles than this particular subset of problems. Redshift quantization has two contexts: one is redshift distortions (from the science end) and one is that a lot of nonstandard proponents support these ideas. To adequately address the subject in this article we should have discussion of both. I agree that the context for redshift quantization in terms of anti-banger advocacy is well-established in the article, but the context in terms of redshift distortions is lacking. Will I include redshift distortions in the quantization article later? You bet.

Also, if quantization is really a subset of mainstram research in distortions, why isn't it mentioned once in Hamilton's paper that you provided to us? because these observations are really quite a ways outside the mainstream research into the subject. Nevertheless, a quantization would appear in the correlation matrices.

I'm being totally honest in my advocacy and please refrain from your insinuations about my lack of good faith, Flying Jazz. I really do not think this article has enough context to allow for a mention of redshift quantization. I don't pretend that the current article on the subject is good -- but from the singular perspective of non-standard cosmology it works fine. As it stands, I find Ian's suggestion ignorant of my reasons.

--ScienceApologist 22:24, 9 June 2006 (UTC)

In terms of what you and Ian want in or out of articles, I am assuming good faith from both of you and didn't mean to imply otherwise. My problem isn't with your advocacies or with your article contributions. My problem has been with how both of you present arguments in talk pages, but I appreciate the clarity of this last post and the post below. Flying Jazz 00:39, 10 June 2006 (UTC)

Clarification about the context of redshift quantization

As the article is currently written, we discuss the fact that there are mechanisms assumed in mainstream astrophysics for redshift in the introductory paragraph of the section on observations. This serves as an excellent means to mention the minority opinions on redshift in similar fashion to the way in which the issue is treated on the Big Bang page. Two separate mechanisms from nonstandard cosmology are listed: tired light (which is of interest to scientists for historical reasons, not just for anti-banger appeasment) and intrinsic redshifts (which is basically all that nonstandard proponents have left after all other mechanisms are thrown away). I'm still very uncomfortable with including "intrinsic redshifts" at all because I find the idea, aside from being well-outside the mainstream research programs, to be completely opaque with respect to parsimony and falsification. Adding additional unknown parameters is an abrogation of the theoretical constraints on cosmology in a way that's pretty absurd considering that the nonstandard proponents harp about ad hoc designs in standard formulations. Nevertheless, I tip my hat to the fact that the subject is enthusiastically supported by Arp and others and move on.

Now Ian wants to see the words "redshift quantization" appear somewhere in the article. The reason that the nonstandard proponents like "redshift quantization" is because they believe that the observations cannot be explained within the standard paradigm. This is a different subject than alternative mechanisms and so doesn't belong in discussion of alternative mechanisms. Where it might belong is in a discussion of redshift distortions, but the article as it now stands deals only with these in its discussions of peculiar velocities and Fingers of God (which are actually second-order distortions because first order distortions are not easily observed). To really contextualize this presumed "observation" correctly we should include a discussion of how astronomers measure the correlations between redshifts: that is to say we need to discuss the umbrella topic of redshift distortions. The conflation of structure, Hubble flow, and peculiar velocities definitely demands that some level of "redshift quantization" will occur (that's even discussed in the redshift quantization article thought it's refered to their obliquely as a "geometrical explanation"). How much should occur in our universe is hard to characterize and the statistics relied upon by previous investigators has been found to be wanting especially with regards to present datasets. So, I don't see an adequate way to mention the subject of "redshift quantization" in its proper context for this article. I don't think we need necessarily include mention of this at all because the subject itself is obscure even with regards to redshift discussions. We already bend-over-backwards to mention alternative mechanisms in the article that don't need to be included here. As far as I can tell, without the proper context of redshift distortions, redshift quantization is of interest only to nonstandard proponents and I do believe its mere mention without context of how redshift distortions are measured is a violation of undue weight.

--ScienceApologist 22:41, 9 June 2006 (UTC)

How about we set-up a Request for Comments, something along the lines of the following: We're considering adding "Redshift quantization" to the article. Here are the options: (a) We do not include it at all (b) We start a See also list and add it there (c) We add a sentence about it somewhere (d) We added a paragraph about it somewhere (e) As 'd' plus more context on "Intrinsic redshifts" and "tired light".

I've tried to phrase it impartially, with no clue as to pros and cons. I would also suggest that we archive this page, and start a fresh page. If Redshift Quantisation is not required, we leave it out, if the general opinion is to add a paragraph of text, then we do that. --Iantresman 23:34, 9 June 2006 (UTC)

A Request for Comments with five options about such a minor issue would be a terrible waste of people's time in my opnion. Let's keep talking to each other and anyone else who shows up for a little longer. Flying Jazz 00:39, 10 June 2006 (UTC)

SA, when you post "I don't pretend to understand why the anti-bangers like redshift quantization so much" and 17 minutes later post, "The reason that the nonstandard proponents like "redshift quantization" is because..." it seems like you're talking to yourself. Still, I'm sympathetic to your points and I share your views. My view is that pseudoscientists misuse science every way they can. They take old discarded theories like tired light and pretend that new life has been breathed into them. They come up with unfalsifiable catch-all terms like intrinsic redshift and pretend they're discussing a meaningful topic. They pretend that Occam's razor indicates that constants should become variables in order to create theory that ignores what they want to ignore. And they take outdated observations from a scientific sub-discipline (redshift quantization) and pretend that it supports their views somehow. I didn't want tired light or intrinsic redshift in this article because I didn't want to bend over backwards. I was surprised when you wanted tired light mentioned for historical reasons, and since other editors agreed, I backed off. I'm tempted to agree with Ian because the way that alternative-cosmology people misuse redshift quantization is different from the way they misuse the other terms, and I'm interested in a comprehensive summary. But I'm tempted to agree with you because of your point that this misuse is more nefarious for redshift quantization since it is a concept that can be discussed in the context of real science.

For now, I'd like you to help me understand something technical but relevant. You wrote "The conflation of structure, Hubble flow, and peculiar velocities definitely demands that some level of "redshift quantization" will occur." I understand why structure in the universe in the distant past must result in very distant objects having redshifts that cluster around certain values, but I don't see why it would result in having redshifts that cluster around multiples of those values. It seems like structure, Hubble flow, peculiar velocities AND some universe-wide periodicity in structure would be required to definitely demand that redshift quantization will occur. Am I missing something? Flying Jazz 01:31, 10 June 2006 (UTC)

This is an excellent question and it has to do with the way that structure forms. In fact, the "seeds" of structure are fairly regurlar quantum fluctuations that occur before the process of cosmic inflation. We see evidence for this in the anisotropies of the cosmic microwave background radiation. If you look at the WMAP all sky image what is most striking is that the sky is "grainy" on a certain scale. This scale is 1 degree and it represents the very last quantum fluctation that made it through before the universe inflated. After inflation, structure grew from these seeds by means of gravitational collapse. Because these fluctuations are (at least statistically) evenly spaced (mimicing a universe-wide periodicity in structure), we expect to see a statistical regularity to large-scale structure and we do. It corresponds to the regular repetition of galaxy clusters. The issue is that because the universe has had 13 billion years to collapse, this first level of repetition is fast being erased by dynamical effects. We happen to be at the point where the virial radius (what's known in cosmology as the parameter "sigma-8" ) for an overdense region is a bit larger than normal cluster size. So this statistic runs the risk of being randomized. Nevertheless, there are other correlations in the CMB which are larger scale (though not as prominent as the 1-degree anisotropy) and are seen in the "bumps and wiggles" of the power spectrum of galaxy correlations, for example.

Hope this answers your question.

--ScienceApologist 12:08, 10 June 2006 (UTC)

Just a reminder that this is fine theory for which there consistent evidence. No more. --Iantresman 12:22, 10 June 2006 (UTC)

It is a theory that clarifies SA's arguments that there are two possible contexts to include the term redshift quantization and it would be a mistake to only mention the term in passing within a list of terms liked by proponents of alternative cosmologies. Flying Jazz 12:41, 10 June 2006 (UTC)

That's all science is: a collection of theories and observations. No more. --ScienceApologist 14:02, 10 June 2006 (UTC)

• Redshift quantization is not about alternative cosmologies. It's merely a possible set of observations which may have consequences for alternative cosmologies... or it might not. But to assume its only possible relevence is to alternative cosmologies, and that must be pseudoscientific, or it must have been already discredited, or that the only people interested in redshift quantiization must be anti-Big Bangers, does not appear to be an accurate reflection of the science that is going on.
• Tifft's 1997 paper[4] does not seem to show any "dissent" regarding the Big Bang. Likewise his latest 2003 paper[5]. Of course I may have my own opinions, but they are of no relevence.
• Even Bell and McDiarmid's latest paper[6] note that's preferred redshifts "may be intrinsic redshifts or a common selection effect", hardly the conclusion of an ardent anti-Big Banger (even if he is anti-Big Bang... I have no idea). --Iantresman 14:34, 10 June 2006 (UTC)

• "pseudoscientists misuse science every way they can". I trust that there is no suggestion that Tifft (quantized redshifts), Arp (intrinisic redshift) and Zwicky (tired light) were in ANY way pseudoscientists, or that their work is pseudoscientific. They may have alternative observations and ideas, but that does not imply pseudoscience... such a correlation would demonstrate pseudoskepticism (a kind of pseudoscience).
• This answers ScienceApologist's statement: "I don't pretend to understand why the anti-bangers like redshift quantization so much". I would guess that Tifft supported the Big Bang when he discovered redshift quantization, and his position is clear, he write:

"Throughout the development of the program it has seemed increasingly clear that the redshift has properties inconsistent with a simple velocity and/or cosmic scale change interpretation. Various implications have been pointed out from time to time, but basically the work is observationally driven."[7]

• This notion that there is a clique of scientists who do not believe in the Big Bang, and go out of their way to find evidence soley to support their belief, is in itself a miguided belief, and is no different to assuming that their observations, methods and results must be wrong, because we all know that the Big Bang is correct.
• What I do know, is that Wikipedia is not the place to debate all this. It is the place to describe it. --Iantresman 10:38, 10 June 2006 (UTC)

Please maintain focus on the article and please do not reply to posts addressed to SA. Flying Jazz 12:27, 10 June 2006 (UTC)

Very well; I was just concerned that the dialogue appeared to be based on a false premise. I will acquiesce. --Iantresman 12:51, 10 June 2006 (UTC)

Fine structure constant confusion?

I'm interested that Ian was confused about the fine-structure constant reference which is directly applicable to the discussion about the spectroscopic signature of single sources. Do people find the current wording unclear? Would anybody like to suggest an alternative? --ScienceApologist 17:53, 8 June 2006 (UTC)

There are many other examples in the article where a non-scientist would be "confused". The very first sentence: "In physics and astronomy, redshift is an observed increase in the wavelength and decrease in the frequency of electromagnetic radiation received by a detector compared to that emitted by the source." Do you know any non-astronomers? Your parents? Give them a call, and read them the first sentence. I'm not saying that there shouldn't be technical stuff in the article, only that you have to (a) define terms first (b) provide real-world analogies and examples, etc etc. --Iantresman 18:14, 8 June 2006 (UTC)

Do you have any alternative suggestions? --ScienceApologist 18:35, 8 June 2006 (UTC)

Quite a few, which I'll plan to suggest once the trivial matter of redshift quantization is resolved. --Iantresman 19:17, 8 June 2006 (UTC)

Dumbed down introduction

I've dumbed down the first line of the description of "redshift" on the grounds that most readers will not understand terms such as wavelength, frequency, and electromagnetic radiation, and we don't want to loose readers before completing the first sentence. In other words, these are all technical terms with no predefined contexts.--Iantresman 14:34, 13 June 2006 (UTC)

Definitional Disaster

The first line of the description of "redshift" that I'm currently seeing is a disaster. Let's start with the grammar and if time permits, move on to the scientific problems in this and many of the subsequent lines. Here's what I'm seeing:

• "In physics and astronomy, redshift is a phenomenon in which the visible light from an object is shifted towards the red end of the spectrum."

A phenomenon in which? The "shift" isn't IN the phenomenon! It IS the phenomenon, as already stated. This is just a very poor connecting phrase that should be replaced. In fact, the whole approach of the first sentence leaves much to be desired. I'm sure there are many better approaches. To suggest just one....

Redshift is a term used within the broader field of spectroscopy, which is the study of light spectra. When light from an object in an earth-bound lab is put through a prism and spread into a rainbow or spectrum, certain thin emission or absorption lines may appear, always at certain locations along the band of colors. Remarkably, each line corresponds to a particular element such as hydrogen or neon (or a particular transition of an element's electron to another energy level). When the spectrum of light from distant astronomical objects is analyzed, the lines for the specific elements are seen to be shifted compared to their locations when measured in earth-bound labs. The shift for most distant astronomical objects is toward the red end of the spectrum, and they are said to be redshifted. In 1930-something, Edwin Hubble discovered that there is a strong correlation between the amount of the redshift and the distance to the object. Subsequent observations have broadly verified this correlation, although a small cadre of researchers continue to point to certain groups of astronomical objects that appear to be close to each other and gravitationally interacting, yet their redshifts are greatly different, which would indicate that one object is far in the background of the other foreground object....

Well, OK, this isn't easy. But that's no excuse for an inferior presentation. DCougar 04:54, 5 August 2006 (UTC)

• Yes, it's not easy. The start of the first sentence, "..a phenomenon in which?..", I didn't read as a shift "in" the phenomenon, but took "in which" to mean "which is", though I can see that it could be interpretted ambiguously.
• Thanks for your suggested introduction, but I have a couple of comments;

• "Redshift is a term"; I read this as a kind of tautology without conveying as much information as "redshift is a phenomenon"
• ".. broader field of spectroscopy.. "; I would tend to steer clear of technical words so early on, which I think puts off a lot of people. Granted, it is immediately explained in the following clause, but we're still no closer to explained what "redshift" is.

• I wonder whether changing the "in which" is all that we need to do, though I read it as "which is"? --Iantresman 10:01, 6 August 2006 (UTC)

The relative change in wavelength z

• I put all the equations in a single table, I think it improves the layout, and lets readers see the relationship between all of them.

• I added a table of interpretation of the value if z; I'm sure I don't need to ask, but could you please check it for accuracy.

• I added a final paragraph on z as a constant. A single measurement will not determine whether z is a frequency-independent, and in practice, either it is assumed to be frequency-independent, or it is found to be? Is this accurate?

I have never seen someone who has measured redshift using a single feature. In practice, one looks at an entire spectra and then fits the shift. I removed this paragraph for discussion below. --ScienceApologist 18:28, 13 June 2006 (UTC)

On reflection, I realized that the z=10 galaxy mentioned in this very article (aside:I don't believe this measurement. The line was supposed to be asymmetric in the opposite direction according to the paper that made the measurement!) was done with a single line that was claimed to be lyman-alpha because of the context. So, I guess there are always people that will try to stretch these things. --ScienceApologist 19:51, 13 June 2006 (UTC)

• And finally, does anyone know why z was chosen to represent redshift? I think it would make a nice bit of trivia. --Iantresman 16:56, 13 June 2006 (UTC)

Ian's edits

First of all, thanks Ian for your work on the page. It represents a real improvement.

I removed these paragraphs to this page for discussion:

If z is constant over all frequencies (ie. frequency-independent) for an object, then it is sometimes referred to as a Doppler-like redshift. Three types of redshift are Doppler-like: (1) Doppler redshift, (2) Cosmological redshift, (3) Gravitational redshift), and have special significance in astronomy as described in "Redshift mechanisms" below.

If z is not constant over all frequencies, then it may indicate (a) a shift which is not a redshift at all, (see below) (b) a distortion which can provide other useful diagnostics (eg see Doppler broadening.

There are some problems with these paragraphs. First of all, "Doppler-like redshift" just refers to a redshift that is frame-dependent (in other words, you could erase the effect by moving in an appropriate fashion). It really doesn't have to do with the frequency-independent nature of the redshift, though this is definitely a feature. As such, this characterization isn't quite correct.

I am of the opinion that in the strictest sense "redshift" always implies frequency independence. Of course, one can define a "redshift" as a bathochromic shift or "redshift" as associated with various z measurements that are not necessarily frequency-independent, but as far as I know no person who uses "redshift" as a strict term is ever careful in their implications of frequency independence or frequency dependence as this first sentence pretends. So, this attempted bifurcation is really somewhat disingenuous, even though it is technically more careful than how most scientists use the term. I think that the opening to the section on redshift mechanisms does the best job at explaining the difference between redshift mechanisms that are "Doppler-like" and redshift mechanisms which are not "Doppler-like". Frequency-independence just comes along for the ride.

The second sentence is good natured enough, but it doesn't make a lot of sense. First of all "a shift which is not a redshift at all" is a phrase that illustrates the ambiguity associated with what "frequency-dependence" or "frequency-independence" entails. I think that phrasing it like this is utterly confusing. What's more, people can design scenarios (e.g. Wolf Effect) where over large-ranges of spectrum the redshift appears to be frequency-independent. The real distinction is mechanistic, not phenomenological as described here. The other issue is that Doppler broadening, in point of fact, is actually frequency-independent because if the gas clouds are well-mixed, then all features should be doppler-broadened by the same delta z regardless of which frequency you look at. So the second point is technically incorrect.

I think the question we need to ask is: "Do we need these sentences?" If they are trying to explain something to the reader, what exactly is it?

--ScienceApologist 18:28, 13 June 2006 (UTC)

• I'll explain where I was coming from. By definition, z could be argued to be constant (no argument). In practice, the only way to check, is to compare multiple wavelength measurements. Only then do you know if you have a Doppler-like redshift, or something else.

• Yes, this is true, but one always looks at "multiple wavelength measurements". That's the whole point of using a spectrometer and not a "filter".

• If I show you a limited spectrum (perhaps with no lines), you'd never be able to check z. If I should you a spectrum with one line, you could calculate z, but still wouldn't know if it was Doppler-like. If it turned out the spectrum was from scattering, only then might you discover it was frequency dependent, and z was not constant. And although spectra would show redshifted lines.

• A spectrum with one line cannot be fit with a redshift. The whole endeavor requires comparing an observed spectrum of lines to a known sample. --ScienceApologist 18:48, 13 June 2006 (UTC) (addendum: see point above about the example of a group who calculated a redshift with a single line.)

• In other words, the z equation does not determine whether it is constant? --Iantresman 18:44, 13 June 2006 (UTC)

• You are right about this: it's the observations of z which determine whether it is constant. --ScienceApologist 18:48, 13 June 2006 (UTC)

Ian, your questions made me realize that we never really describe in the article exactly how the redshift measurement is done. I have included that in the overview section. --ScienceApologist 18:59, 13 June 2006 (UTC)

Are you sure that z may be less than -1? If we look at the equation, z = (λo - λe)/λe for λo>>λe and λe→0 (redshift), then we get z = ∞/0 = ∞. However, for λo<<λe, λe→0 then we get -∞/∞= -1. --Iantresman 20:03, 13 June 2006 (UTC)

z indeed has a lower bound at -1, but that's a mathematical truism and isn't really germane to the discussion. It doesn't really illustrate anything other than the conservation of energy and the underlying poisson-constraints on the distribution of energy. --ScienceApologist 20:15, 13 June 2006 (UTC)

Ready for FA?

Any outstanding problems with this page that would prevent it from being renominated as an FA? --ScienceApologist 20:54, 13 June 2006 (UTC)

Sorry, but I have a some more to suggest, but am getting side-tracked on other issues. --Iantresman 13:26, 14 June 2006 (UTC)

Please hold off for another few weeks. I'd like to take a look at the article with "fresh eyes." Flying Jazz 18:26, 14 June 2006 (UTC)

Catastrophists, creationists, and even geocentrists

I am inspired by ScienceApologist's addition of this sentence to the article on Redshift quantization[8], to add the comment. I am happy to discuss its inclusion and motive as it applies to BOTH articles. --Iantresman 13:26, 14 June 2006 (UTC)

It doesn't belong on this article because redshift quantization doesn't belong in this article. --ScienceApologist 13:36, 14 June 2006 (UTC)

This section did not contain additional content relating to Redshift as a topic, so it was moved to Talk:Redshift/Content Moved From Redshift Quantization Dispute June 2006. Please move all talk about this particular edit there. Flying Jazz 20:43, 7 June 2006 (UTC)

Cosmological statement

The 2004 New Scientists letter questioning Big Bang cosmology appears fair and relevent to cite in the reference to "alternative redshift theories". The letter mentions:

These and other alternative approaches can also explain the basic phenomena of the cosmos, including .. how the redshift of far-away galaxies increases with distance. (My emphasis)

--Iantresman 20:07, 14 June 2006 (UTC)

Burbidge and Reboul both deal specifically and exclusively as their subject materials with redshift. The Open Letter mentions it as a side issue. --ScienceApologist 20:29, 14 June 2006 (UTC)

The redshift article mentions specifically "nonstandard cosmologies". The letter is SPECIFICALLY on nonstandard cosmologies, AND redshift is SPECIFICALLY mentioned in their open letter. --Iantresman 21:19, 14 June 2006 (UTC)

Both of you are using flawed logic. If a Wikipedia article A mentions a topic B, and if a letter C about that topic B mentions the subject of the article A, whether the letter (C) mentions it (A) as a "side-issue" (of B) or mentions it "specifically" doesn't matter to the reader. It also doesn't matter to other editors here. I think Ian's sentence: "In 2004, New Scientists published a letter from a number of scientists questioning Big Bang cosmology." doesn't teach the reader anything about redshift, so it shouldn't be in a Redshift article. Flying Jazz 17:56, 15 June 2006 (UTC)

• The sentence wasn't provided to teach, but to verify the article statement that "Alternative hypotheses (for example, tired light and intrinsic redshift suggestions from nonstandard cosmologies)", demonstrating that there are indeeed scientists who do indeed consider redshift/alternative cosmologies.
• The original reference, noted "one of the few remaining astronomers who argue for intrinsic redshifts" which I considered an unverifiable perception, and the only verifiable source which suggests that there is not just "a few remaining astronomers", is the one I provided. --Iantresman 18:45, 15 June 2006 (UTC)

I have no issue with Burbidge and Reboul. --Iantresman 22:02, 14 June 2006 (UTC)

Redshift criticism (refactoring confusion)

I've restored this section. Flying Jazz removed discussion he felt concerned redshift quantization. This section is SPECIFICALLY about criticisms of redshift, as indicated by all the statements and sources.

• I've discovered a significant and notable source of criticism on redshift, which I think we should consider including the article. The source is impeccable[9], and it notes many critics. The source mentions:
• "... many opponents of the Big Bang including Halton Arp" and indeed there do appear to be hundreds of such critics [10].
• The source also mentions creationists critics, and its primary source[11] does indeed make extensive comments on redshift (there are also a few comments on redshift quantization, but they are not relevent here). A second creationist source provided, also has an associated paper [12] that also criticises redshift.
• It is estimated that there are some 100+ million creationists in the USA alone,[13] and this must represent a significant view.
• There's also a reference to a group called modern geocentrist, where I note an associated critical paper also on redshift [14].
• I am a little reluctant to use Web sites as sources, but the empeccable source noted above, seems ok with it. I note that the Cosmological Statement was published in the reputable New Scientists, which I suspect felt that the reliability, and credibility of the original signaturees was notable. About 200 of the other signers all appear associated with academia.
• It does seem odd that we don't have a section on Redshift criticism when there are so many critics. --Iantresman 19:24, 16 June 2006 (UTC)

I did not refactor that post because I felt it concerned redshift quantization. I refactored that post because it was uncivil and detached from the Redshift article as a topic. It was uncivil of you to misapply ScienceApologist's post in the Redshift quantization article in this way as if it were a justification for you to list a series of bulleted points that continue your uncivil behavior of disrupting Wikipedia by preventing other editors from focusing on individual detailed topics. If you want a "redshift criticism" section then propose one in a way that other editors can understand and respond to so that the community is stronger and more good editors post here. Don't write a bunch of bullet points that are only connected to each other in your mind and then write "It does seem odd that we don't have a section on Redshift criticism." We cannot read your mind and we're getting sick of trying. Please, please stop making these lists of bullet points that all say something different and baiting and provocative and just write ONE THING about what EXACTLY you want in the Redshift article so we can try to rebuild the community of editors that used to post here before your behavior spiralled out of control and took the talk page down with it. If you want to change the article, write about how you want to change the article and leave out this nonsense. Flying Jazz 22:32, 16 June 2006 (UTC)

Oops. Scratch nearly all that. I didn't refactor that post at all. ScienceApologist did. That was a mistake. SA, you should not be refactoring the talk page when you are the target of incivility. The post should have been refactored, and probably would have been eventually, but you shouldn't have done it, and you shouldn't have done it so soon after it appeared. You, SA, are contributing to the confusion and nonsense here, as usual. See Wikipedia:Refactoring and my concerns about refactoring getting out of hand. Honestly, you two deserve each other. Flying Jazz 23:27, 16 June 2006 (UTC)

Back to Redshift Quantization

Summary of prior debate (about redshift quantization)

I'd just like to say that my rants towards Ian and SA in the previous section were about specific talk-page behaviors, but they weren't about the two of you as editors. I'm glad you're both here. I just hope we can maintain better focus so more people come here. The redshift quantization dispute remained unresolved. My summary of the dispute is that everyone agrees on a couple things:

1) Redshift quantization is discussed in verifiable sources.

2) Redshift quantization has serious implications for cosmology.

Ian views this topic as worth mentioning. ScienceApologist disagrees. ScienceApologist's view is that, if the topic is mentioned, it should be mentioned in its proper context. His argument is:

3) Redshift quantization is one of many different types of redshift distortions.

4) If Redshift quantization were included outside of the context of other redshift distortions, this would be misinterpreted by the reader to indicate that redshift quantization is a more prominent subtopic and more important than it really is.

5) Including a survey of redshift distortions would overburden the article with technical content inappropriate for a general purpose encyclopedia.

6) Redshift quantization is therefore insufficiently prominent to include in the article.

My own (perhaps biased) summary of the controversial subject hanging over the dispute is:

7) The serious implications of redshift quantization on cosmology are often presented by proponents of alternative cosmologies as if this would support their views. The truth-value of this presentation is dubious at best.

8) This has led to a prominence for redshift quantization in alternative-cosmology sources that is somewhat larger than its prominence in mainstream cosmology sources.

9) This has also led to a prominence for redshift quantization in non-scientific (pseudoscientific, advocacy, etc) cultural sources and in pro-science (refuting) cultural sources that is somewhat larger than its prominence in scientific sources.

Please let me know below this post if you two agree with this summary, but include debate in the next subsection. Flying Jazz 05:34, 17 June 2006 (UTC)

A fair summary, I'd say. --ScienceApologist 06:26, 17 June 2006 (UTC)

I wholly disagree that redshift quantization has an association with "pseudoscientific, advocacy", on so many levels (refactored by Flying Jazz 13:24, 17 June 2006 (UTC)) --Iantresman 12:34, 17 June 2006 (UTC)

Ian, please see google here, here, and here for many examples of cultural sources, non-mainstream and pro-mainstream, that do not appear in scientific literature. Using the words "pseudoscientific, advocacy, etc" may have been poor word choice on my part. If I replace this summary with:

9) This has also led to a prominence for redshift quantization outside of the scientific literature in non-mainstream cultural sources and in refuting mainstream cultural sources that is somewhat larger than its prominence in the scientific literature.

do you agree? Please don't post in the subsection immediately below until we can all agree on these statements. Flying Jazz 13:24, 17 June 2006 (UTC)

Further debate (only about the context for inclusion/exclusion of redshift quantization in the redshift article)

My inability to decide about this is a result of wanting redshift quantization mentioned at redshift because of point 9, but still wanting to do this "properly" in terms of treating a science concept like a science concept. I don't buy SA's argument for exclusion, but I recognize my previous position was ill-informed and of course I no longer want redshift quantization mentioned only in the same sentence with tired light and intrinsic redshift. With some skill (that I don't have but that I know exists), it should be possible to include enough context for redshift quantization in the article to properly indicate the actual prominence of redshift quantization in physics and to refer the reader to the redshift quantization article for details. As for all the other redshift distortions and their technical details, it is possible to let the reader know there is much more to the story without revealing the story. Flying Jazz 05:34, 17 June 2006 (UTC)

This is a very interesting proposal. I would love to see what this would look like. I'm all for setting up a workshop to work this out. --ScienceApologist 06:26, 17 June 2006 (UTC)

Further debate (additional comments by Ian about redshift quantization)

• Mere mention of redshift quantization in a creationist publication does not imply support by all creationists. If the Economist magazine runs an item on gay rights, do we assume that all Economists are gay?
• Every reference we cite is based on the content of the article, not on whether Tifft, or Napier was a creationist (it would be an ad hominem to suggest it was relevent). I can find nothing which suggests that Tifft or Napier set out to find data supporting or not supporting the big bang. The closest texts I can find, is that IF there is redshift quantization, then there may be implications for big bang cosmology.
• The verifiable facts are: (a) there was observational evidence to support it, (b) there is currently evidence which some authors claim is inconsistent with it, and (c) evidence which some authors claim is not inconsistent with it. This summary is verifiable (refactored by Flying Jazz 13:24, 17 June 2006 (UTC)) --Iantresman 12:34, 17 June 2006 (UTC)

Nobody disputes your first comment. I think your second and third comment belong in Talk:Redshift quantization. Not here. Flying Jazz 13:24, 17 June 2006 (UTC)

Redshift criticism (Ian's proposal)

• For every "creationist source" mentioning redshift quantization there are more "creationist sources" criticising the wider subject of "redshift". In other words the "association" is not limited to redshift quantization, and if this was a "problem", then it's a problem for "redshift" too.
• In other words, all the references to pseudoscientific advocacy is weak and unreliable, and IF it applies to redshift quantization, must apply at least equally to redshift in general.
• I think that one of the problems with redshift article concerning redshift quantization, is that we have tried to marginalise all critical comment, so there is no obvious place for it. While there may be a good argument that EACH critical theory is too minority to include, as a whole, there are many credible sources (eg. the Cosmological Statement in New Scientists) criticising some aspect of redshift. Why do so many academics/engineers have a "problem" with aspects of redshift, that include redshift quantization?
• A solution I propose is a section on "Redshift criticism" (only a couple of paragraphs), which begins with Zwicky's "tired light" alternative (and the problems with scattering), mentions "intrinsic redshift" as an alternatives, or component, of Cosmological redshifts, and that redshift quantization may or may not be relevent too. (refactored by Flying Jazz 13:24, 17 June 2006 (UTC)) --Iantresman 12:34, 17 June 2006 (UTC)

My issue with a section called "redshift criticism" is that nobody will know what the heck that meeans. Google gives zero hits on "redshift criticism" or "redshift critic." Redshift is an observation that nobody seems to disagree with. Sources don't criticize redshift. They criticize the way that redshift observations are used to fit one theory or a different theory. I think those criticisms, if they should be included somewhere, belong in pages about the theories. Including them here as if the critics are criticizing redshift would misrepresent countless people and would just be a disaster. Flying Jazz 13:24, 17 June 2006 (UTC)

• I partly agree with that, though I note that there are nearly no Google references to either "Big Bang criticism" [15], nor "tired light criticism" [16], but we know that there are. Are we just quibbling over the name of such as section? "Redshift interpretations" perhaps?
• I think that part of the problem is that we don't clearly differentiate between undisputed redshift observations and "redshift theories". The current "Redshift mechanism" section is a mix of observation and theory.
• I find that the "Overview" is the best section we have, based purely on the observation and measurement of redshift... and I digress slightly, I think that content of this section is more than just an overview, and perhaps should be called "Redshift observation and measurement", and perhaps expanded.
• But there is nothing on how an observed redshift, leads us to "deduce" that a particular redshift value has a Doppler component, Cosmological, and Gravitational redshift components. Doppler is easy: I can measure the redshift, I know the speed of light, and out pops a velocity. But I get stuck with the Cosmological redshift.
• Some text connecting observational redshift with redshift mechanisms, I feel is lacking. And the natural consequency of this, is some discussion on additional interpretations.
• The "Redshift mechanisms" section doesn't help itself, by beginning with a contrived condition about "a single photon propagated through a vacuum"; redshifts are not observed through a vacuum, nor a single photon at a time. And if observed redshifts are more important and undisputed then, why is the Wolf effect marginalised, when it is observed and demonstrated, and acknowledge in references as a valid mechanism. --Iantresman 14:39, 17 June 2006 (UTC)

About your first point, I'm not quibbling over the name of your proposed section. I am arguing my position that your proposed section should not exist in the article at all. It seems to me to be a continuation of your previous arguments on this talk page over the past year to have a list of certain things set aside in this article instead of considering each of those things one-by-one in terms of whether it should be included and where and how it should be included to best serve the reader. For example, the long debate about the Wolf Effect resulted in its inclusion and in its present location and context, and I don't find that location and context to be marginal because it was the result of a good debate that had the reader in mind. Your other points are interesting and might be useful too in creating a better article, but right now we are trying to discuss the location and context of redshift quantization in the redshift article, and I hope you join in the debate in the section above by paying close attention to my changes to the summary of prior debate, and then joining the current debate. Otherwise, you'll most likely be complaining in a few weeks or months about how the article deals with redshift quantization just like you're complaining now about how the article deals with the Wolf Effect. And when you do that, I'll just laugh at you. For now, I hope you abandon this section and talk up there about what the other editors are talking about. Flying Jazz 16:50, 17 June 2006 (UTC)

As an observation, redshift quantization must go in the "Observations in astronomy" section. There are two further options (1) Include it in the introductory paragraphs where we find intrinsic redshift (2) Move the intrinsic redshift sentence, and together with redshift quantization, create a new sub-section on "Other observations". This gives us the space to fully contextualise redshift quantization, and more full contextualise intrinsic redshift and tired light. It would also give us the opportunity, if we wanted, to add more examples that don't fit into the rest of the article. --Iantresman 17:29, 17 June 2006 (UTC)

Overview change

I moved the useful "observational" information from "Overview" to a new section called "Observing and measuring redshift". The existing section "Quantifying and interpreting redshift" naturally follows on as a sub-section. --Iantresman 11:18, 20 June 2006 (UTC)

Going way back in time

We once had more on the relativistic Doppler redshift. It was removed because editors other than myself believed it was too cumbersome and not illuminating enought to include. The problem is that the v used the formulae is not the same v as appears in the Lorentz factor. The relationship between them is that the "redshift" v is the velocity in the line of sight (or the velocity of the Lorentz factor multiplied by cosine of the angle between the motion and the line of sight). The formula Ian put up had the two velocities switched. --ScienceApologist 14:19, 20 June 2006 (UTC)

Sounds reasonable, perhaps the fuller equation can go in the ariticle on Relativistic Doppler effect. --Iantresman 14:49, 20 June 2006 (UTC)

It's technically already there, just substitute in for the ratios of the frequencies 1 + z. --ScienceApologist 14:52, 20 June 2006 (UTC)

Frame transformations

ScienceApologist, can you clarify the following:

• Doppler redshift is due to Galilean transformation (ie. due to movement)?

yes. --ScienceApologist 18:02, 20 June 2006 (UTC)

• Relativistic Doppler effect is a combination of the Galilean transformation (the Doppler part), and the relativistic part is due to which? Lorentz or relativistic transformation? The name suggests one, the Lorentz factor the other. (ie. due to spacetime?)

The relativistic Doppler effect is due to a Lorentz transformation. --ScienceApologist 18:02, 20 June 2006 (UTC)

• Cosmological redshift (expansion of space) is only Galilean transformation (due to motion)?

In actuality, this redshift is due to a general relativistic transformation associated with the FRW metric. --ScienceApologist 18:02, 20 June 2006 (UTC)

• Gravitation redshift is only general relativistic transformations (ie. due to time dilation)? --Iantresman 16:20, 20 June 2006 (UTC)

yes. The metric that is used is the Schwarzschild metric for a stationary mass.--ScienceApologist 18:02, 20 June 2006 (UTC)

• Thanks for that. Is there a metric associated with the Galilean transformation?

yes, it's $ds^{2}=dx^{2}+dy^{2}+dz^{2}$ --ScienceApologist 18:12, 20 June 2006 (UTC)

• And presumably at low speeds, the Lorentz transformation approximates to the Galilean transformation?--Iantresman 18:08, 20 June 2006 (UTC)

yes. --ScienceApologist 18:12, 20 June 2006 (UTC)

Does the Galilean transformation have a name, formal or descriptive? Thanks. --Iantresman 18:15, 20 June 2006 (UTC)

By this, I assume you are asking if the metric associated with the Galilean transformation has a name. The metric is in fact the Euclidean metric. --ScienceApologist 18:18, 20 June 2006 (UTC)

Is the Lorentz transformation metric the Minkowski metric?

yes. --ScienceApologist 19:06, 20 June 2006 (UTC)

Michel's letter

This article states under Gravitational redshift: This letter has been considered to be the first prediction of gravitational redshift.

As time dilation is not the same as light speed or light intensity, the association is incorrect and can only lead to confusion. The source that makes that erroneous claim isn't mentioned while that's obviously required; and apart of that, the whole passage is in fact irrelevant for this article; it may be appropriate for event horizon. Harald88 09:12, 25 June 2006 (UTC)

I think it was me who found details of the letter. Whether it is considered the first prediction of gravitational redshift, I don't know. That some people had considered it so, I read somewhere. I shall defer to the widsom of the other editors --Iantresman 09:26, 25 June 2006 (UTC)

If you can trace back which journal had considered it so, it may be still be worthy of mention in the event horizon article. Harald88 09:36, 25 June 2006 (UTC)

This book says that the Gravitational redshift was predicted by Michel and Laplace, with a more detailed explanation here and here. --Iantresman 10:25, 25 June 2006 (UTC)

Those cites are to the first prediction of the Schwarzschild radius. The book does not claim that Michell/Cavendish suggested a gravitational redshift. LaPlace is usually credited with being the first to theorize an object like a black hole, but the correspondence of Michell and Cavendish do seem to come in second place. --ScienceApologist 10:34, 25 June 2006 (UTC)

I moved the sentence, with modification, to the black hole article. --ScienceApologist 10:39, 25 June 2006 (UTC)

Intrinsic redshift

• Well done ScienceApologist, another unilateral decision; you final got the heretical tired light and intrinsic redshift out of the main article, but you forgot the Wolf Effect. If you make the font size of the footnotes even smaller, you can make sure that no-one can even see the words "tired light" and "intrinsic redshift". I shall look forward to your next article in Pravda. --Iantresman 22:22, 5 July 2006 (UTC)

• So the CfA survey is of questionable historical interest, so we leave it in, yet only the second redshift mechanism to be demonstrated in the laboratory for 150 years (as described in the literature), isn't. --Iantresman 23:15, 6 July 2006 (UTC)

• Incidentally, the Optics Society of America has some 15,000 members, [17], whereas the American Astronomy Society has but 6500 members [18]... from which we calculate that Undue Weight give the Wolf effect just two words. Disgraceful. --Iantresman 00:10, 7 July 2006 (UTC)

Joshua certianly engages in a lot of conduct unbecoming a sysop, guess this is just more proof that he's unfit for the job--F.O.E. 06:51, 7 July 2006 (UTC)

Observation vs theory

The article is more concerned with the observation of redshift, of the theory of redshift? Presumably the latter is more conjectural? --Iantresman 21:40, 17 July 2006 (UTC)

While one can divide scientists into observationalists and theorists, this particular subject doesn't really separate out that cleanly into the two categories. Observing a "redshift" can only be explained through appeal to some theory. That's one of the constraints of astrophysics, our captive audience can't ever see behind the curtain so we have to be clever in how we look for the mechanisms. --ScienceApologist 22:26, 17 July 2006 (UTC)

Alternative redshift theories

I've replaced the statement "Alternative hypotheses are not generally considered plausible" which is subjective and dependent on who you ask.

The new statement accurately reflects the number of verifiable published papers on alternative hypotheses (600+ is not insignficant), and a number of scientists and engineers who have acknowledged that they consider alternative redshifts to be plausible. Again 200+ scientists and engineers is not insignficant. --Iantresman 10:22, 18 July 2006 (UTC)

No, the new statement violates WP:NPOV#Undue weight. It has been reverted. --ScienceApologist 14:29, 18 July 2006 (UTC)

• How many peer-reviewed papers and scientists discussing alternative redshift theories, exceeds Undue Weight? --Iantresman 15:09, 18 July 2006 (UTC)

In the article as currently written we have a decent coverage for alternatives with respect to their prominence. --ScienceApologist 15:26, 18 July 2006 (UTC)

• That's not what I asked. How many peer-reviewed papers and scientists discussing alternative redshift theories, exceeds Undue Weight? How do we independently assess it, rather rely on your perspective --Iantresman 15:35, 18 July 2006 (UTC)

The question you asked is meaningless for our discussion. There are no hard-and-fast rules in Wikipedia. We are human editors, not computer programs. --ScienceApologist 15:40, 18 July 2006 (UTC)

• It currently seems that you are the sole arbiter of what constitutes Undue Weight. I'd like your description of how others may judge what exceeds Undue Weight. I have read Wiki's policy on Undue Weight several times over, and I think I have grossly misunderstood it. --Iantresman 16:07, 18 July 2006 (UTC)

Redshift mechanisms

I've changed the introduction to this section to clarify that (a) we are not implying that there are ONLY three mechanisms (we don't know if any of the hundreds of alternative mechanisms are significant), and (b) to clarify the "single photon in a vacuum" is a hypothetical characteristic, on the grounds that in practice, observed redshifts do not involve (i) single photons (ii) do not take place in a vacuum. --Iantresman 10:38, 18 July 2006 (UTC)

It is not ours to judge what mechanisms are significant or are not significant. The fact remains that the three mechanisms listed are more significant according to the mainstream journals than any of the alternatices. The "single photon in a vacuum" isn't hypothetical, it's a practical simplification so that models can be distinguished. Observed redshifts do involve the aggregate of single photons and inasmuch as they interact with space that has a smaller density than anything we can create on Earth, they propagate through a vacuum. These are neither controversial nor inaccurate facts. --ScienceApologist 14:32, 18 July 2006 (UTC)

I didn't judge them. I stated that "In astrophysics, all redshifts are considered to be due to a combination of three different mechanisms". Is this statement inaccurate? --Iantresman 15:12, 18 July 2006 (UTC)

That statement is misleading. The context of the observations determines the mechanism. Generalized to "astrophysics" in general doesn't help elucidate. --ScienceApologist 15:27, 18 July 2006 (UTC)

But "A single photon propagated through a vacuum can redshift in three distinct ways." is also not very helpful because there are no such observations which depend on one photon, and on a vacuum. In which case, why are we applying this so-called simplification to real-life? --Iantresman 20:32, 18 July 2006 (UTC)

That's like asking why do we say that the acceleration due to gravity is constant when it really varies? It's for simplicity of explanation and it happens all the time. --ScienceApologist 20:36, 18 July 2006 (UTC)

"A single photon propagated through a vacuum can redshift in three distinct ways." implies ONLY three ways, which is subjective. Emil Wolf would disagree with this. Dan James would disagred with this.

"A single photon propagated through a vacuum can be considered to redshift in three distinct ways." No dispute.

• And you still haven't answered my question on Undue Weight above --Iantresman 00:12, 19 July 2006 (UTC)

Undue weight

ScienceApologist, I still do not know how to assess undue weight. You're able to decide what fails Undue weight, but unable to explain what doesnt't. --Iantresman 11:15, 24 July 2006 (UTC)