One of Astronomy's pet crackpot theories: non-cosmological quasar redshifts

In the standard Big Bang theory of cosmology— a theory that explains a wide range of observations— distant objects show a shift in the observed wavelengths of features in their spectrum as a result of the expansion of the Universe. In between the time when the light is emitted by a distant object, and the time that we see that light, the Universe expands. The wavelength of the light goes up by a relative factor that has the same value as the relative expansion in the size of the Universe. This effect is called cosmological redshift. Because the Universe has always been expanding, we can use this to measure distance to an object, and to measure how far back in time we're looking (i.e. how much time it took the light to reach us). The more redshift we see, the more the Universe expanded, so thus the more time the Universe was expanding while the light was on its way to us, and thus the longer the trip to us was.

Astronomy has long had a handful of fringe scientists who argue that at least some of the redshifts we see are non-cosmological in origin. In particular, Halton Arp, most famous for a catalog of galaxies with disturbed morphologies (as a result of interactions), argues that quasars aren't really cosmologically distant objects at all, but are rather objects ejected from nearby galaxies, showing their redshifts as the result of an extreme Doppler shift due to their high ejection velocities. He based this originally on anecdotal observations of quasars with much higher redshifts seemingly correlated with much more nearby galaxies on the sky. For a long time, it was hard to test this correlation quantatively, for the selection effects were huge. By and large, we targeted interesting objects, but there were other interesting objects in the field. So, of all the quasars known, there was an observational bias that there would be more known near other objects that were observed for other reasons.

Various other things are claimed together with quasars supposedly being ejected from galaxies. In particular, there are claims of periodic redshifts— that is, that quasars are preferentially observed at certain redshifts, or at certain redshifts relative to the redshift of the galaxy that supposedly ejected them.

With the advent of large-scale sky surveys such as the Sloan Digital Sky Survey (SDSS), it has become possible to statistically test these predictions. Of course, the vast majority of astronomers haven't bothered, because we have extremely good models of quasars as cosmological objects that explain a wide range of observations about them, meaning that there's really no need to pay attention to the crank fringe asserting that there must be something wrong with the mainstream model. However, this (rational) response does feed into the natural tendency of many people to be attracted to conspiracy theories, who then assert that the "dogma" of mainstream science is "ignoring the evidence" for these decidedly non-conventional models of quasars. So, a few people have used the data in the SDSS to look for correlations of quasars and foreground galaxies, or to look for evidence of periodic redshifts in quasars. The result, of course, is that there is no evidence to support these theory, and indeed that the large statistics afforded by these surveys support the cosmological model.

In other words, if you want it summed up in fewer words: Arp is wrong. The evidence does not back up his arguments.

(He will disagree, and if you go to his website you can see the paranoia on the nicely designed, sparse front page. However, even if he is right about being ignored by the mainstream of science, that is because the mainstream of science has good reason to ignore him.)

Su Min Tang and Shuang Nan Zhang did a careful statistical analysis of SDSS data to look for the effects of periodic redshifts in quasars, and for correlations between quasars and galaxies. In other words, they took the predictions of Arp and his followers seriously, at least for purposes of performing the analysis. I've already stated the result above: no effects observed. Here is one of their "money" plots, Figure 7 from that paper:

Tang & Zhang, 2005, Figure 7

The circles here are the data from the sky survey. The various lines are the results of simulations, with the error bars on the lines showing the scatter in the simulations. The solid line is the only one that's consistent with the data throughout the whole range. The various dashed lines are simulations that would result of quasars were ejected from galaxies at various different velocities.

Reference to Arp's work is also part of the larger net-crank alternate astronomy theory, "plasma cosmology" (and the even more cranky, if that were possible, "electric universe" notion, as well as modern day followers of Velikovsky). That this lynchpin has been completely debunked should hopefully help you conclude that plasma cosmology isn't anything that should be taken seriously. I hope to address more of that in later posts.

26 responses so far

  • James says:

    I dig it! I'm so glad to finally read about some science done to test Arp's claims and would love to read more articles like this. I once very nearly bit onto the lure of plasma cosmology, and still haven't satisfied that part of me which was drawn to it in the first place.

  • Gordon Lamps says:

    Again I am dismayed that "crackpottery" is being used as part of a so-called scientific argument. It should be the reader that concludes this, and not the author who tries to foist this description on them.

    If there is one thing I have learned from science, it is that it is not always concrete and final in its theories. Looking further into the literature (not popular web sites), it appears that the discussion is not over.

    For the record, I have not thoroughly read through and assess all the arguments, and I will except that they may even be wrong. But hopefully if they are wrong, it is for a good scientific reasons, and not because someone considers the author to be a "fringe" scientist/crackpot.

    Bell, M. B.; McDiarmid, D. R, Six Peaks Visible in the Redshift Distribution of 46,400 SDSS Quasars Agree with the Preferred Redshifts Predicted by the Decreasing Intrinsic Redshift Model
    http://adsabs.harvard.edu/abs/2007astro.ph..1093B

    Bell, M. B., Further Evidence That the Redshifts of AGN Galaxies May Contain Intrinsic Components
    http://adsabs.harvard.edu/abs/2007ApJ...667L.129B

    And for balance, other papers disagree with these, see for example:

    Repin, Serge V et al, Absence of a Periodic Component in Quasar z-Distribution
    http://adsabs.harvard.edu/abs/2010arXiv1011.0611R

  • rknop says:

    Gordon -- did you read the post? The post is referring to a paper that pretty much takes apart the notion that there was anything to that.

    The reason I refer to this as crackpottery is because that's what it is. When it was first proposed, it was fine. However, holding on to that model now is crackpottery. It's long been not reasonable, and long been out beyond the fringe. It would be similar to holding on to the geocentric Earth or on to some form of creationism, or to the Aristotelean description of motion. Yeah, sure, there are a few of the fringe people out there who still publish papers saying that their ideas are right but... they're not. There is a gigantic amount of weight for the mainstream view, and they're rightfully ignored.

  • Gordon Lamps says:

    I also don't accept that one paper necessarily demonstrates that a theory is wrong when there are other papers criticizing it. We see what the critics have to say first, assess their comments, go back to the scientific method (remember that), and then you explain why the critics are wrong before coming to your conclusions.

    You don't win an argument but just claiming that something is crackpot. I'd expect a crackpot to use that kind of reasoning. Aristotle may have had a nutty idea of motion, but we don't call him a crackpot .

  • rknop says:

    It's not just one paper. Every paper written that has to do with cosmology, plus many other astronomical papers (anything dealing with objects at redshifts more than .01 or so) either explicitly or implicitly use cosmological redshifts. The bar for showing that is wrong is EXTREMELY high. The paper I described above was very thorough in looking for the effect, and it is not there. A trickle of papers from True Believers is not a reason for us to question a well-established understanding. The evidence against that understanding has to be extremely compelling-- and it's not. The only people who think it is are the true believers, and they seem not to be able to be convinced by evidence against their ideas. They hold on to yhem long past the point where they are viable. That's what makes them cranks.

  • Gordon Lamps says:

    It's not the trickle of papers that makes us reconsider cosmological redshifts, but what those papers might say, and the evidence they might have.

    I think you're saying that of the papers you have read, you have not found any compelling evidence to question cosmological redshifts. That's fine. On the other hand, if you're saying that you have faith that no-one could presents any kind of evidence in a paper to shake your faith, then I would question who are the "believers".

    Science works by doing science, not by counting papers, and labelling people.

  • Siggy_G says:

    Alternative Cosmology Group has a page (www.cosmology.info) containing newsletters with monthly references to recent eye-opening or eye-brow-lifting papers published in arXiv, related to astronomical interpretation and cosmology. The amount of papers highlighting uncertainties and problems with the big bang model (and what it should predict) is so numerous that it's not even funny. Yet you, Rob, claim something along the lines of "we already know how the universe works" and "the standard model explains everything extremely well" and pretty much dismiss out of hand papers questioning the standard model. There's a lot of sincere scientists/astrophyscisists that try out new approaches, based on observation, because new data surprisingly (for some) often contradict or challenge the established models.

    For instance:
    Observational evidence favors a static universe
    http://arxiv.org/PS_cache/arxiv/pdf/1009/1009.0953v2.pdf

    "Abstract: The common attribute of all Big Bang cosmologies is that they are
    based on the assumption that the universe is expanding. However exam-
    ination of the evidence for this expansion clearly favors a static universe.
    The major topics considered are: Tolman surface brightness, angular size,
    type 1a supernovae, gamma ray bursts, galaxy distributions, quasar dis-
    tributions, X-ray background radiation, cosmic microwave background ra-
    diation, radio source counts, quasar variability and the Butcher–Oemler
    effect. An analysis of the best raw data for these topics shows that they
    are consistent with expansion only if there is evolution that cancels the
    effects of expansion. An alternate cosmology, curvature cosmology, ia a
    tired-light cosmology that predicts a well defined static and stable universe
    and is fully described. It not only predicts accurate values for the Hubble
    constant and the temperature of cosmic microwave background radiation
    but shows good agreement with most of the topics considered. Curvature
    cosmology also predicts the deficiency in solar neutrino production rate
    and can explain the anomalous acceleration of Pioneer 10."

  • Nereid says:

    I'd like to echo Rob's comment, Gordon; did you actually read those papers?

    The Bell ones in particular are almost textbook examples of how to really, really mess up (in astronomy).

    Siggy_G, you too seem to have a very uncritical view; for example, you seem to accept that every preprint (not paper!) addressing some aspect of concordance cosmological models in a negative way, on arXiv, is sound.

    Oh, and nice deflection; in a blog entry about the Arpian 'intrinsic redshift' crackpot nonsense, you write a post about something else entirely. I hope this doesn't sound rude, but do you do this deliberately? Or are you quite unaware that you keep changing the subject?

  • Gordon Lamps says:

    My criticism is how the subject to treated. Arp and Bell are not wrong because they are "crackpots", or because he is a "textbook examples of how to really, really mess up".

    Science has a way to show whether the facts are incorrect, and unfortunately, it requires a bit of time, effort and explanation.

    So if indeed there is something critical of Bell's paper, then please provide an explanation in layman's terms, of where his science/facts are incorrect. I do not claim that Bell (or Arp) are correct.

  • Nereid says:

    "This catalogue should not be used for any statistical analysis as it is not complete in any sense, except that it is, we hope, a complete survey of the literature."

    Do you know where that comes from Gordon? What can you say about any paper which bases its statistical analyses (etc) on data from that catalogue (other than analyses of 'the literature')? HINT: you don't need to read any part of any such paper, beyond determining whether the author followed this 'should not' (or not).

    In any case, you've got the shoe on the wrong foot; as Rob already pointed out, the 'burden of proof' is on folk like Arp and Bell, not on Rob, you, me, or anyone else to explain - in layman's terms or otherwise - why some stuff that makes it into arXiv (or even ApJ) is incorrect.

    Of course, there are several good internet discussion fora where you can get answers to questions such as yours - Physics Forums, BAUT, Starship Asterisk*, JREF, to name just a few - provided you phrase your questions thoughtfully and appropriately ('Bell PROVES Arp was right! Astronomy community is suppressing inconvenient results! Arp is a modern day Galileo!!' for example is not to be recommended).

  • Siggy_G says:

    Nereid,
    How is my comment about papers/pre-prints by sincere astrophysicists/theorists that point out issues with an expanding universe NOT relevant to this blog entry? In other words, this is a blog entry belittling those who question the expansion (recession speed) interpretation of redshift, while portraying the standard model as factual and non-questionable. And, it's not just one paper, nor just one pre-print, I'm referring to - there are numerous, by people compentent within their fields.

    Sure, practically all astronomical objects have a measured redshift, pretty much proportional/increasing with distance, to the extent one can cross-verify those distances - but is that increased redshift only possibly explained by an expanding universe? My point is, there are numerous papers questioning both this redshift interpretation and/or an expanding universe, so they're not unrelated or irrelevant to the subject of this blog, which is "redshift = expansion (and don't ask questions)".

  • Nereid says:

    "How is my comment about papers/pre-prints by sincere astrophysicists/theorists that point out issues with an expanding universe NOT relevant to this blog entry?"

    Because, Siggy_G, the blog entry is devoted almost entirely to Arp's crackpot notions.

    Gordon, the most concise explanation of why Arp (and others who claim quasars are at distances wildly different than what their Hubble relationship redshifts point to) goes something like this:

    Quasars are just AGNs (active galactic nuclei), differing only in scale (however defined) or viewing geometry from Seyfert nuclei, BL Lac objects, blazars, type 2 quasars, etc. They are, in other words, a homogeneous class of 'real' astronomical object, not a heterogeneous one.

    Arp (and all the others I know of) accepts this.

    Therefore, establishing that just one AGN is cosmologically distant is sufficient to demonstrate that they all are (otherwise they'd be a heterogeneous class).

    There are, in fact, hundreds of such examples; they are called 'lensed quasars': a foreground object (usually a galaxy) acts as a gravitational lens, producing multiple images of the one, background, AGN (usually a quasar).

    Case closed.

  • Gordon Lamps says:

    Nereid wrote: "In any case, you’ve got the shoe on the wrong foot; as Rob already pointed out, the ‘burden of proof’ is on folk like Arp and Bell, not on Rob, you, me, or anyone else to explain"

    Of course. For all I know, and anybody else reading this discussion, Arp and Bell may have already presented a burden of proof, because the only arguments I read against them are:

    1. They are crackpots
    2. We have our own explanation.
    3. We're under no obligation to criticize their work.

    The only thing I haven't read, is why aspects of their work may be wrong,

  • Nereid says:

    "The only thing I haven’t read, is why aspects of their work may be wrong" (Gordon Lamps)

    Gordon, are you, perhaps, merely skimming what's written (and not actually reading it)?

    Did you not read the following in my post, the one immediately above yours?

    "the most concise explanation of why Arp (and others who claim quasars are at distances wildly different than what their Hubble relationship redshifts point to) goes something like this:

    Quasars are just AGNs (active galactic nuclei), differing only in scale (however defined) or viewing geometry from Seyfert nuclei, BL Lac objects, blazars, type 2 quasars, etc. They are, in other words, a homogeneous class of ‘real’ astronomical object, not a heterogeneous one.

    Arp (and all the others I know of) accepts this.

    Therefore, establishing that just one AGN is cosmologically distant is sufficient to demonstrate that they all are (otherwise they’d be a heterogeneous class).

    There are, in fact, hundreds of such examples; they are called ‘lensed quasars’: a foreground object (usually a galaxy) acts as a gravitational lens, producing multiple images of the one, background, AGN (usually a quasar)." (Nereid)

  • Gordon Lamps says:

    Lensed quasars is an acceptable theory, but Arp's theory does not negate it, nor vice versa.

  • Nereid says:

    Gordon, I don't think you're paying attention (or, perhaps, you simply don't understand the relevant results).

    Start with AGNs as a homogeneous class. In arXiv:0711.2607, Arp makes it abundantly clear that he regards AGNs to be just that (e.g. "If active galaxies are defined as extragalactic objects with appreciably non thermal spectra then a continuity exists in redshift from the highest redshift quasars to low redshift Seyferts, AGNs and allied galaxies. ")

    Next, lensed quasars. As far as I know, Arp has commented on them precisely once, in his book Seeing Red. And in that book he comments on precisely one such, the "Einstein Cross". His words on this topic, in that book, make it clear that he recognises full well how fatal lensed quasars would be to his entire thesis (though it must be said he does this indirectly). Since the book was published, in 1998, dozens of lensed quasars have been reported (I think the number is now well over 100). Yet not a peep from Arp on any of this; why?

    A reminder: what do lensed quasars show? That quasars are background objects, far more distant from us than the galaxy doing the lensing; indeed, analysis of these lensed quasars shows that they are at distances from us consistent with the redshifts, per the Hubble distance-redshift relationship (and there are some papers on using lensed quasars to independently estimate the Hubble constant, providing a completely independent means of confirming the consistency of other methods).

    May I ask how you arrived at the - bizzare - conclusion that "Arp’s theory does not negate it, nor vice versa"?

  • Gordon Lamps says:

    It is not surprising that the public does not understand the (scientific) results. The public do understand that calling people crackpots does not necessarily make them wrong.

    Your reply is getting better, in that it is explaining why Arp etc may be wrong.

    My point, explained poorly, is that just because someone has a theory, does not automatically make other people's theories, incorrect. So just saying that you have a better theory, does not automatically make a poorer theories wrong.

    So I think you are saying that gravitational lensing explains Arp's non-cosmological quasar redshifts, in that the gravity from certain cosmic objects, magnifies them like a lens, and makes then seem closer than they really are.

    Would this imply that gravitational lensing distorts cosmological redshift, and all of Arp's quasars just happen to lie behind a gravitational lens?

  • rknop says:

    Gordon -- the fact that two theories are incompatible does not make one of them necessarily false.

    However, the fact that the broad range of cosmological and astronomical observations are consistent with cosmological redshifts and inconsistent with Arp's ideas do, in fact, make Arp's theories false. They're in the graveyard of astronomical ideas, along with the classic steady-state Universe, the gravitational contraction powered Sun, and the geocentric solar system.

    People who argue that the Earth is at the center of the Solar System in this day and age are, yes, crackpots. I will allow you to draw the obvious conclusion.

    As for "Arp's quasars" -- take a look at the ORIGINAL POST of this comment thread. There is no statistical correlation between galaxies and background quasars. That Arp, in a biased sample, is able to produce anecdotal evidence that would seem to indicate quasars associated with a galaxy doesn't mean squat

    Arp is wrong. The evidence shows he is wrong. You may want to cling to his theories, but in so doing you're clinging to theories because you like the way they sound, not because the evidence supports them. That's not how science works. Sorry.

  • Nereid says:

    Gordon, Arp's theory (if you can call it that) is that:

    a) redshifts are not a reliable indicator of distance, in general (i.e. that the Hubble distance-redshift relationship doesn't work very well) - and is completely unreliable for quasars (i.e. that the Hubble distance-redshift relationship doesn't work for them, period); and

    b) quasars are ejected from the nuclei of (active) galaxies, and are 'local' (they are approx 10 to 15 mag fainter than their 'parent' galaxies; you do know that a 'magnitude' is, in astronomy, don't you?).

    In this Arpian idea, if a quasar were as distant as its redshift implies (per the Hubble relationship), then it would be completely invisible (it'd be far, far too faint), no matter how much brighter gravitational lensing made it appear. In addition, if a quasar were so much further from us than the galaxy (acting as the lens), it couldn't possibly have been ejected from it (Arp's ejection idea requires that quasars travel no more than ~half to one megaparsec from their 'birthplace', which is less than 1% of the estimated difference in distance for lensed quasars).

    So, to your questions:

    "So I think you are saying that gravitational lensing explains Arp’s non-cosmological quasar redshifts, in that the gravity from certain cosmic objects, magnifies them like a lens, and makes then seem closer than they really are."

    No. I'm saying that Arp's idea is inconsistent with the observations of 'lensed quasars', period.

    "Would this imply that gravitational lensing distorts cosmological redshift, and all of Arp’s quasars just happen to lie behind a gravitational lens?"

    No. Gravitational lensing does not affect redshift.

    Further, there's no such thing as "Arp's quasars"; the objects are what they are - point sources in the sky, say - irrespective of who first reported observations of them.

  • Gordon Lamps says:

    I am not clinging onto anyone's theory, just criticising the description of the arguments against him. My point is that to convince people other than scientists, an easy to understand description of the problems is required. It is not easy.

    The statistical analysis maybe crystal clear to you. It's not to lay people. That may mean having to go the extra mile in describing the paper's analysis. It is not easy when the public may think that there are lies, damn lies, and statistics.

  • Nereid says:

    Gordon, from your comments here, would it be fair to say that you really didn't (and still may not) have much understanding of what's Arp's crackpot idea actually is?

    If that's so - and I welcome any demonstration that you did, in fact, grasp at least the core concepts of Arp's crackpot idea - then you seem to be saying (demanding?) that others put considerable time and effort into educating you, not only on why Arp's idea is a crackpot one, but also into educating you on what that idea actually is!

    Do you not see the irony here? The absurdity?

    'Tell me why {X} is a crackpot idea! {insert angry emoticon here}! (I've no idea what X is; all I know is that someone said it was a crackpot one ... for all I know, if I'd taken the time and trouble to actually try to understand it, I might have been able to work out why it's a crackpot idea, all on my own, using nothing more than just my own critical thinking capabilities)'.

  • Gordon Lamps says:

    Wow, 6 uses of the word "crackpot" in one post. Aren't you the clever one. It's quite a contrast, the impartiality and respectfulness of science, to the vindictive name calling of its so-called adherents.

    Making fun of people's ideas by people who know better, is cheap, and does you a disservice.

  • Hannes Alfven says:

    Those who possess even a modest familiarity with Halton Arp's arguments should be highly dubious of the analysis presented on this page. The following statement does not fully address the possible causes for the *intrinsic* redshift, whether it's an accurate representation of Arp's claims, or not. And that means that this analysis should be rejected as an incomplete rebuttal for the claim of intrinsic redshift:

    "Astronomy has long had a handful of fringe scientists who argue that at least some of the redshifts we see are non-cosmological in origin. In particular, Halton Arp, most famous for a catalog of galaxies with disturbed morphologies (as a result of interactions), argues that quasars aren't really cosmologically distant objects at all, but are rather objects ejected from nearby galaxies, SHOWING THEIR REDSHIFTS AS THE RESULT OF AN EXTREME DOPPLER SHIFT DUE TO THEIR HIGH EJECTION VELOCITIES."

    To my knowledge, the intrinsic component to the observed raw redshift is *quantized*. Thus, how does it even make any sense that ejection velocities would be the inferred cause? What causes the quantization? What we are seeing here, by necessity, is a microscopic process playing out in a macroscopic manner.

    There is arguably a large set of explanations which could be tapped into to explain this observation of quantized inherent redshifts. Ejection velocity is hardly one of the more convincing inferences.

    One idea which has emerged from the EU camp is that, observationally speaking, there appears to exist an increase in the mass of the quasars as the quantized redshift in quasars falls. This is an important aspect of Arp's observations which was noteworthy enough to end up in the documentary, "The Cosmology Quest". It also appears quite clearly on page 108 of Seeing Red, Arp's explanation for his observations, where he states:

    "Now comes a key point: If the mass of an electron jumping from an excited atomic orbit to a lower level is smaller, then the energy of the photon of light emitted is smaller. If the photon is weaker it is redshifted ... it suffices here to understand that lower-mass electrons will give higher redshifts and that younger electrons would be expected to have lower mass."

    The point here is that the analysis presented on this page does not appear to reflect the full argument which Arp and others are making. So, it appears to me that you are (intentionally or not) confusing people.

    One way to explain intrinsic redshift is as quantized changes in energy levels of electrons, protons and neutrons within the atom. Within the EU view, the masses of subatomic particles change in response to electrical stress. In an Electric Universe, that includes magnetic and gravitational stress. Wal Thornhill argues that increasing negative charge on bodies increases their mass and gravity (see "Orbital Energy" in http://www.holoscience.com/news.php?article=q1q6sz2s).

    So, how could we reconcile this? One way -- and I'm just throwing this out there as an example -- would be to realize that the plasmoid formed in a plasma gun is the most copious beamed source of neutrons known. So, most of the mass ejection will be neutral and decaying, once free of the plasmoid's electromagnetic influence, into protons and electrons (nascent hydrogen).

    The second fact is that electrons, being much lower in mass than protons, will remain entangled in the plasmoid in greater numbers and for longer than protons. Also, strong electric fields in the plasmoid will tend to separate the electrons and protons, giving oppositely directed beams.

    There are almost surely other inferences which could explain the full set of observations. But, the trick is in getting people to leave their comfortability zone of the gravitational framework sufficient to postulate plasma physics explanations. Whatever the proposed explanation is, it needs to be proposed within a plasma universe framework. This is where most conventional thinkers go wrong: They fail to absorb the plasma universe materials sufficient to even make such propositions.

    It always amuses me when people point to a statistical analysis in order to prove that somebody else's theory is wrong. Yes, it is unfortunately common today, but there exists a very large set of misconceptions or dirty tricks which can bias the results to accommodate any pre-existing worldview. The human mind oftentimes looks for shortcuts to avoiding uncertainty. We oftentimes want to believe *something*, and it might as well be that which we've been already taught.

    Furthermore, many of the bridges that Arp points to are startlingly apparent to the human eye, once the proper spectra are included. That you decide to focus upon the statistics instead of the stronger bridge evidence, I think speaks to your desire to fight the battle on terms which the general public cannot understand. You are essentially winnowing down the set of people who can argue against you.

    An arguably far better way to test Arp's theory would be to look for "quantum graininess" in particle mass increases within particle acceleration experiments. But, I suspect that your intentions do not so much align with curiosity as they do with an attempt to justify your current belief system. So, I don't expect that you would follow up on such a suggestion, or even think anything of it if the hunch was confirmed. This is what happens when physicists are trained in just one theory. It is not so much a product of science, as it is human psychology. Teaching a student one theory suggests memorization. Critical thinking -- which results from a process of comparing and contrasting -- does not truly begin until the student is taught two competing sets of ideas.

  • martin says:

    I agree with Alfvren. I have read all of Arp's work. No where does he suggest that the redshift of quasars is due to ejection velocity.

  • rknop says:

    Well, OK -- he does have this idea that redshifts are ALSO non-Doppler. But he is saying that Quasars are ejected from galaxies, not cosmological objects. You can find papers as recent as a few years ago where he still says this. It's interesting that he and a few of his friends hold on to this idea even though when *anybody else* does a statistical analysis they don't get the result he says that he keeps getting. He's a classic case of somebody who can't let go of his idea in the face of its failure to be reproduced. That's why science requires a community, and open communication, to work. Individuals can always fool themselves.

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