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Space Science

200,000 Elliptical Galaxies Point the Same Way 448

Posted by kdawson
from the axis-of-opportunity dept.
KentuckyFC sends us to arXiv, as is his wont, for a paper (abstract; PDF preprint) making the claim that 200,000 elliptical galaxies are aligned in the same direction; the signal for this alignment stands out at 13 standard deviations. This axis is the same as the controversial alignment found in the cosmic microwave background by the WMAP spacecraft.
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200,000 Elliptical Galaxies Point the Same Way

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  • Re:Why? (Score:5, Insightful)

    by WormholeFiend (674934) on Thursday August 30, 2007 @11:51AM (#20413163)
    Mind you, does it really matter? Given our very short lives in the grand scheme of things, the lack of knowledge probably isn't hurting us.

    We have short individual lives, but the knowledge that we discover outlives us.

    If one day our descendants find ways to travel beyond our solar system, this knowledge might prove useful to them.
  • by peter303 (12292) on Thursday August 30, 2007 @12:08PM (#20413433)
    An initial anagular momentum for the universe might prejudice galaxy formation.
  • Re:Why Not? (Score:3, Insightful)

    by polar red (215081) on Thursday August 30, 2007 @12:20PM (#20413633)

    but a point that is equally far from every other point in the universe
    I guess that means that at a center point in non-time/non-space, time and space just started ... which means that at that moment, ALL space was a single point, which means that that point is now smeared all over the universe ? something along those lines ? Any1 a physicist here ?

  • by Ancient_Hacker (751168) on Thursday August 30, 2007 @12:42PM (#20413957)
    200,000 galaxies sounds like a lot. But it's not. It's less than one part per thousand.

    And there's no way to tell how closely they're aligned, maybe many are 20-30 degrees off.

    Would you still call that aligned? Is it still significant if one in a thousand galaxies are within 30 degrees of each other in orientation? Who knows? Who cares?

  • by gatkinso (15975) on Thursday August 30, 2007 @12:45PM (#20414009)
    Talk to me at a trillion.
  • Re:Why? (Score:5, Insightful)

    by TinyManCan (580322) on Thursday August 30, 2007 @01:28PM (#20414587) Homepage
    Perhaps they did not have any clue as to the 'why' but thought that the data was interesting enough to warrant further research.

    This is a great way to get working on the 'why', as without this paper no one would be looking at it.

    This is one way that science is done. They probably postulated that the alignment of galaxies would be random, and when they tested this hypothesis they found that the data did not match. Publishing that result so that others can start working on it is the next step in this process.

  • Re:Why Not? (Score:4, Insightful)

    by shma (863063) on Thursday August 30, 2007 @01:32PM (#20414639)
    Rather, the fact that the universe has no 'center' is a POSTULATE of big bang theory. The assumption is that the universe is isotropic and homogeneous, i.e. that the universe looks the same in any direction from any location. While this is obviously false on small scales (the center of the sun, for instance, does not look the same as a point on the surface of the earth), on scales large than the largest structures, on the order of hundreds of megaparsecs, you can begin to see evidence for it. The best evidence for isotropy comes from the cosmic microwave background radiation, which is the same in any direction up to one part in 10^5. These small inhomogeneities in the background imply small inhomogeneities in mass density at the time it was created, 600,000 years after the big bang. Those regions of increased mass eventually formed the galaxies we see today. Getting back to your original question, assuming isotropy and homogeneity, there can obviously be no center of the universe, because it would have to stand out from other points. Likewise, if there was a preferred axis of revolution for all galaxies, then the universe would not be isotropic. That's why this claim is a bit difficult to accept, given the massive success of big bang theory.
  • Re:Why? (Score:3, Insightful)

    by wanerious (712877) on Thursday August 30, 2007 @01:58PM (#20414927) Homepage
    So, anyone want to put odds on dark matter going the way of the cublical atom in, say, ten years?

    What's the relationship between the angular momentum of the Universe and the rotational velocity anomalies of outlying material in galaxies or intra-cluster excess mass? How would that account for the dark matter gravitational lensing results from last year? I'm not seeing why one has such an effect on the other.

  • Re:Why? (Score:5, Insightful)

    by smoot123 (1027084) on Thursday August 30, 2007 @02:12PM (#20415093)
    The three most important words in science are not "I've got it!" but "Gee, that's odd."
  • by MorpheousMarty (1094907) on Thursday August 30, 2007 @02:23PM (#20415223)
    At least the paper is written in such a way that it can be properly criticized. So many slashdot articles are along the lines: check this out, wouldn't it be cool if this crazy idea had some proof! Cosmic dust lifeforms comes to mind from a few days ago. It was an interesting read, and thank you for constructive criticism. Good luck on your paper, and please do check the numbers if you have the time... it seems he did control the numbers to get such a grand conclusion, but perhaps there is a statistically relevant phenomenon here.
  • Re:Why? (Score:5, Insightful)

    by beckerist (985855) on Thursday August 30, 2007 @02:41PM (#20415443) Homepage
    Why? Why admit that "they don't know why" when the data might be right there! You have to keep in mind, to discover these sort of patterns comes from completely indirect viewing. This was all done by observing redshift which means that only one in hundreds of characteristics were monitored. That's like saying "200,000 people are overweight" by knowing that they eat at a fast food joint 3 times a day. There will be some inaccuracies and one could only draw that conclusion by other, much closer observation. Moreso, the statement made was "200,000 galaxies are pointed in the same direction." -- not incorrect!

    My point is that they could very well have the reason "why" in their data, but chances are it would require a much further in-depth study of the individual galaxies themselves (or at least the common threads between them.) To get this pushed out the door now it at least gives others (and probably more qualified individuals) a chance to then take this data and run. Patience, we'll probably get the "why" (or at least some solid theories) soon enough, young Padawan!
  • Re:Why? (Score:5, Insightful)

    by MontyApollo (849862) on Thursday August 30, 2007 @02:46PM (#20415551)
    I don't know how it works with astrophysics and cosmology type stuff, but in other fields of physics, research is often divided between experimentalists and theorists. It might be the case where the author doesn't feel qualified to say why and thinks it would be better for theorists to jump in. Or he may think it is more important to establish is results and have them verified first before moving on.

    Also, if he did try to explain it, then it could really slow down how long it takes to get published because of the peer review process. His explanation would probably be highly questioned, and it would take longer to reach agreement with the peer reviewers. That might be why he said it was beyond the scope of the paper. He wanted to get the less controversial material out there first, then he could concentrate on the more controversial material in a different paper.
  • by hypersql (954649) on Thursday August 30, 2007 @03:10PM (#20415847)
    For 1-D people that live in an expanding 2-D ring, everywhere is the center.
    For 2-D people that live on an expanding 3-D ballon, everywhere is the middle.
    We 3-D people live in an expanding 4-D universe, for us everywhere is the middle.

    That means if you go forever in the same direction,
    you will eventually end up where you started.
  • Re:Why? (Score:5, Insightful)

    by mr_mischief (456295) on Thursday August 30, 2007 @03:15PM (#20415901) Journal
    That is one reason for something to be beyond the scope of paper. Another is that the paper has already hit the publisher's word limit. A third is that the topic at hand has been narrowly discussed for clarity or for time restraints on the project. A fourth is that the paper could become unwieldy if tangential topics are included.

    It could be a combination of any or all of those. "Further research is needed to determine why this is so" is not so vague, and could be used if that was the exact meaning intended.
  • Re:Why? (Score:4, Insightful)

    by bughunter (10093) <bughunter&earthlink,net> on Thursday August 30, 2007 @03:17PM (#20415925) Journal
    Well, beyond the scope or not, they did discuss it briefly, pointing out other papers that may lend insight.

    But one possible cause they did not address is selection bias. Have they shown that they did not introduce any selection bias in the sampling of galaxies? I would hope for at least a list of hypothetical sources of bias that they then shoot down.

  • Re:Why? (Score:5, Insightful)

    by Alsee (515537) on Thursday August 30, 2007 @03:59PM (#20416501) Homepage
    I'll see your "Gee, that's odd" and raise you an "oops".

    -
  • Re:Why? (Score:3, Insightful)

    by bazorg (911295) on Thursday August 30, 2007 @03:59PM (#20416507) Homepage
    "WTF" plays an important role too.
  • by ukemike (956477) on Thursday August 30, 2007 @05:01PM (#20417393) Homepage
    Everyone is asking "why?" as in "Why are they aligned." My first thought was, "What the hell are they all pointing at?" Is it God? Is it the Restaurant at the End of the Universe? Is it Mecca? Maybe it is just a REALLY big magnet. The answer to the 'what' question might go a long way toward answering the 'why' question.

    Anyway since I don't think that galaxies are likely to change their orientation, and remain tidy spiral galaxies, this suggests that there was a common influence on the creation of all of these galaxies!
  • by Anonymous Coward on Thursday August 30, 2007 @05:09PM (#20417507)
    I'm not saying he should be dismissed because of his reputation (or lack thereof). My complaint is that such things send up red flags that should keep articles like this from being treated on Slashdot as verified scientific discoveries.

    The trouble with saying that "anyone who wants to can look at the pictures..." is that there's far more to astronomical data analysis than just downloading the raw data and running your favorite tests on them. The ellipticities in this sample, for example, are calculated in the data pipeline from a very simple geometrical measurement. To actually use them to find an effect this small requires additional reduction. For an idea of what's involved with this particular data set, take a look at this paper [arxiv.org], which uses the same data towards a different end, but likewise requiring precise measurements of the ellipticity and position angles. As you can tell by a glance at section 2.2.2 (and references therein), there are a whole host of instrumental calibrations that have to be done and selection effects to be investigated, and which Dr. Longo ignores. (Someone upthread also mentioned some of these.)

    So the issue is not that Dr. Longo dares to work outside his field. It's that he doesn't seem to know how to go about doing what he wants to, and doesn't want to get his work checked by the people who are experienced in doing this kind of stuff and dealing with the nastiness that is modern astronomical instrument calibration. There are actually quite a few high energy folks who have made the switch from high energy to astrophysics (one is on my committee), and they learn that you can't take a list of raw numbers from a astronomical data catalog, run some binning and simple curve fitting on them, and expect to get a meaningful result any more than you could easily discover the top quark from the raw events list of a particle detector. Also, as I say, there is some dubious use of statistics, but the main point is that he's starting from data that simply isn't yet usable for his task.

    As far as your naked-eye hunches, I suspect that it's an unintentional selection bias (by you) or something. The idea of checking for galaxy alignments is not new--indeed, it's a fundamental test of cosmic isotropy--and an effect large enough to be noticed by the naked eye would've been measured by now. I don't doubt what you think you saw, but I do doubt that you could see a real effect that easily.

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