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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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  • Why? (Score:5, Interesting)

    by bcmm (768152) on Thursday August 30, 2007 @12:21PM (#20412715)
    Do they give any reason that this might be so? Are the galaxies in the same area? Did they all form from some insanely massive rotating structure or something?
  • by massivefoot (922746) on Thursday August 30, 2007 @12:26PM (#20412769)
    Huh. I don't really have a great deal of specialist knowledge on cosmology, but this seems to put a lower bound on the distance over which we can assume the universe is isotropic (i.e. the same in all directions). The abstracts puts an upper bound on the redshift of the galaxies involved in the survey, which is presumably roughly equivalent to limiting the distance they are from us, but surely the fact that this net angular momentum axis is closely aligned with an axis identified in WMAP data indicates that this is a far larger scale phenomenon?
  • which beam (Score:2, Interesting)

    by deopmix (965178) on Thursday August 30, 2007 @12:26PM (#20412773)
    All i want to know is which beam is making them all align. I'm betting that it's shardik's beam, he's bad ass.
  • Re:Why? (Score:5, Interesting)

    by iluvcapra (782887) on Thursday August 30, 2007 @12:32PM (#20412871)

    It might mean that the angular momentum of the universe is nonzero, if a majority of them are turning the same direction. Or, even if they all cancel out, that momentum in the early universe tended to be oriented in a plane. (IANAP, just a guess but seems logical)

    I'm curious if the Milky Way is a part of the alignment.

  • by pla (258480) on Thursday August 30, 2007 @12:35PM (#20412923) Journal
    this seems to put a lower bound on the distance over which we can assume the universe is isotropic

    I have to wonder - Could this particular anisotropy account for the Voyager paradox? That would set a much lower bound...

    Even if not, though, I really find this sort of anomaly fascinating. Almost everything cosmology has found since the dawn of modern science has pointed to a bleak, cold, basically empty univers that goes on identically forever in every direction. Even learning that the universe has some underlying structure would somehow seem a lot more comforting.
  • A grain of salt (Score:4, Interesting)

    by Stranger4U (153613) on Thursday August 30, 2007 @12:36PM (#20412937)
    I read the article, and there seem to be a few problems he doesn't really address. First, he assumes that all elliptical galaxies have a point-of-view from which they appear circular. I don't think anyone has determined this to be the case, and he doesn't really have a way to get this from his data. Secondly, he doesn't give much real discussion to the error in the measurements, which is significant. No preffered axis of alignment would fall well within his measurement uncertainties. Finally, the 13-standard deviations is not from any real sort of error propagation, but from some random computer generated results. Could be interesting, but to be taken with a grain of salt.
  • Why Not? (Score:5, Interesting)

    by NReitzel (77941) on Thursday August 30, 2007 @12:42PM (#20413041) Homepage
    Einstein did not say that there cannot be a center of the universe.

    What he did say is that for the purposes of measurement, there exists no privleged metric. All this says (All?!) is that there is no overall coordinate system that will be superior to all other coordinate systems.

    If things started out as a big bang, on some scale, we will find a "center" of the universe. Is this an astronomy-shaking discovery? No. Maybe a tremor or two, for diehard relativeists. We already know that for specific purposes, there is often a preferred metric for computational or navigational purposes. Remember back in the Apollo program when the physics guys tried to explain that at a specific point, the coordinate system for the spacecraft shifted over from Terra-centric to Luna-centric, and the reporters looked at the "jog" in the plot and asked if the spacecraft would feel a "lurch" as it passed this point?

    It's not nearly as big a deal as, say, whether Pluto is a "planet" or not. Pick a label, pin the sticker on the rock, except in this case, the rocks are superclusters of galaxies.
  • Re:Why? (Score:5, Interesting)

    by fygment (444210) on Thursday August 30, 2007 @12:44PM (#20413063)
    The author states that the reasons for the orientation are beyond the scope of the paper. But the implication of the orientations is that the universe is not spherical. I have had only one course in cosmogeny (origins of the universe) and all the models lead to symmetry. So any indication of a lack of symmetry implies that we are missing some big piece of the puzzle. Combine this with the tenousness of many of the theories of cosmology (eg. Big Bang ... far from perfect and getting further ) and the picture emerges that there is not a lot that is actually known about the structure of the universe. Despite all the bravado and pat statements in the media, all we have are half-baked guesses. 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.
  • Re:Why? (Score:3, Interesting)

    by SQLGuru (980662) on Thursday August 30, 2007 @01:08PM (#20413441) Journal
    Or maybe the universe is spherical but with a much larger radius than we ever expected......two points, close together on the surface of a rather large sphrerical object would have almost parallel paths to that center.......

    Layne
  • Re:Translation? (Score:5, Interesting)

    by Vellmont (569020) on Thursday August 30, 2007 @01:12PM (#20413509)

    can someone give me the 'play by play' brief on the significance of the orientation of the galaxies and why the chance is so slim that they align as they do?


    I'm not a Cosmologist, but one would expect galaxy orientation to be pretty much random. As an example, think about if you threw a bunch of nails in the air. At any given time you'd expect the nails orientation to be pretty random (ignoring air effects, and any bias given by your throw). If they all aligned in a certain way though, you'd be surprised and start looking for a cause. (In this case say a strong magnetic field in the room).

    If this is true, there must be something orienting the alignment of galaxies. That could be either some bias in the big-bang, some outside force we don't understand, or something else.
  • Re:Why? (Score:2, Interesting)

    by Anonymous Coward on Thursday August 30, 2007 @01:25PM (#20413689)
    The alignment is not especially surprising, but the explanation offered is probably not correct, or at least not that important. If you have rotating gravitating bodies, like galaxies, they will exert torques on each other. Given a lot of time to act - literally billions of years - you might well produce such an alignment over the vast distances involved. The magnetic explanation conjectured in the paper seems unwarranted, but is probably an effort to account for the electromagnetic background anisotropy at the same time. A very neat analysis of a lot of data though!
              IAAP, but don't want to be understood as criticizing the author.
  • Re:Why? (Score:5, Interesting)

    by ATMD (986401) on Thursday August 30, 2007 @01:30PM (#20413769) Journal
    OK, I may be making a fool of myself here, but how can the entire Universe's angular momentum be non-zero? Surely momentum can only ever be relative to your frame of reference - and by definition, any frame of reference you can think of will be within the system you're trying to measure.

    Although... thinking as I type here... say you were sitting on a massive spinning top, and all you could see was the spinning top. You'd still feel centrifugal force, as a result of its spinning. Could be an interesting explanation for dark energy?

    (and yes, now I remember that important word "inertial" from A-level Physics lessons. Meh...)
  • by JohnnyDanger (680986) on Thursday August 30, 2007 @01:47PM (#20414033)
    This paper has no discussion of the ellipticities caused by imperfections in the telescope optics. This is a well known problem for weak gravitational lensing and cosmic shear measurements, which also use measured ellipticities. This problem can be corrected by using the stars (which should be round at the telescope resolution) to figure out and fix the distortions in the image.

    I have little direct experience with this, but I suspect that optical distortions could be the cause of the effect he is seeing. The universe may very well have some weird features, but this paper is not a careful analysis.

  • by joh (27088) on Thursday August 30, 2007 @02:43PM (#20414755)

    I have to wonder - Could this particular anisotropy account for the Voyager paradox? That would set a much lower bound...


    There's not only the Voyager anomaly (which we have very poor data of and may have totally conservative causes).

    Much more interesting is the Flyby anomaly [wikipedia.org], an unexpected and unexplained energy (velocity) increase during Earth flybys of satellites (or probes). It has been observed with at least four satellites yet and seems to show that our understanding of gravity/mass is subtly wrong in a very fundamental way.
  • Re:Why? (Score:3, Interesting)

    by bromoseltzer (23292) on Thursday August 30, 2007 @05:03PM (#20416551) Homepage Journal

    I'm curious if the Milky Way is a part of the alignment.
    Yes, it is, more or less: (from the FA)

    Elliptic Galaxy Axis 183±8 deg 41±8 deg
    North Galactic Pole 192.9 deg 27.1 deg
    1st no. is right ascension (longitude for stars), second is declination (latitude).

    This is really an amazing result. The galaxies way over there on the "left" side of the Universe know what the galaxies on the "right" are doing! It's so amazing, it makes you wonder if it might be wrong. For example, it might really be a property of some more local grouping of galaxies. Don't take it at face value -- yet.
  • by FuzzyDaddy (584528) on Thursday August 30, 2007 @06:15PM (#20417557) Journal
    "Fingers of God" is unrelated to the current paper. Fingers of God is an apparent anisotropy, while this paper describes an actual anisotropy.

    The fingers of god effect is simple - the doppler shift of a galaxy is proportional to the distance, according to Hubble's observations. If you do a plot of galactic positions, using the observed position in the sky and the red shift as the third dimension, you see what appear to be long, skinny clusters, all pointed directly at you. This happens because in tight clusters, galaxies are attracted to each other gravitational and have a range of velocities which is relatively large. So there's an added velocity on top of that caused by the expansion of the universe, which changes the distance you'd compute by Hubble's law.

  • by pldd (1136557) on Thursday August 30, 2007 @06:55PM (#20418055)
    I guess that if a high-energy physicist can some of his time to learn some basic astrophysics (like measuring galaxies alignment). We clearly recognize the work of a particle physicist here: 1) Longo defines his measurement; 2) He selects and describes his sample; 3) He does his analysis by comparing the data with Monte Carlo data; 4) He concludes and indicates the confidence level of his analysis. That`s a pretty robust method which generates most results in experimental particle physics. If Longo`s analysis is correct, it could indicate a coupling between the angular momenta of the galaxies (like the spins of the nuclei in a solid which generate ferromagnetism through Ising coupling). There could be several domains of aligned galaxies in the Universe (since Longo looked only at a close region), like polycristallic iron. This discovery could even give us information about dark matter if we suppose that the galaxies are loosely aligned on a vector field. A wild hypothesis could be that this vector field is the (spin-1) interaction field of dark matter particles, which would be required to be fermions.
  • Re:Why? (Score:4, Interesting)

    by Maury Markowitz (452832) on Thursday August 30, 2007 @09:03PM (#20419247) Homepage
    > Brans-Dicke theory and it shows nothing about angular momentum

    You're right. That sucks.

    Basically the idea behind BD, and the other ST and STV theories, is that there is an additional field, not just the tensor field of GR. One of the side-effects of the field in the BD theory is that angular momentum "falls out" of the universe. This is actually kinda important.

    In traditional models, the conservation laws you know don't really _have_ to exist. For instance, if the universe was shaped like an egg, billiard balls would always roll into one corner of the table because there's more mass on that side of the universe. The fact that it is conserved says a lot about the universe, specifically that is symmetric around any point in 3-space. Conservation of angular momentum is similar; it says the universe is symmetric around other axis as well -- linear momentum would still be conserved in a universe shaped like a cigar, along any axis the gravity is still even, but in this case a spinning object would speed up and slow down. Conservation of energy is due to the fact that the universe is symmetrical in time, physics in the past is the same as it is today.

    Ok, but like I said, those laws don't _have_ to be true, and this bugged the hell out of a lot of people over the years. I forget which one of them, I think Brans, was thinking about what would happen if you spun a dish full of water in an empty universe... would the water rise up the sides? And if it doesn't, why not? Isn't either answer a little weird?

    The extra field in DB theory answers the question -- the answer is "yes", the water will rise up on the sides. It wasn't designed to do that, at least I don't think so, but it ends up popping out of the math.

    So basically if you end up with odd angular momentum terms in the universe, it MAY suggest that some other model of gravity might be more correct. Right now everything we've ever measured can't tell between the various models, but this might.

    Maury
  • by gregor-e (136142) on Thursday August 30, 2007 @11:40PM (#20420461) Homepage
    In an oscillating universe, intelligence that is around at the end of a 'big crunch' will, of course, attempt to arrange things so that out of the next 'big bang', intelligence will precipitate sooner and will have some sort of leg up on understanding what is going on. So, kind of like the guy in the movie 'Momento', they tattoo the universe in ways that they hope will ultimately be decipherable to a future naive intelligence. Communication via matter arrangement preceeding a 'big crunch' is a pretty tough thing to pull off. One doesn't know what the future precipitant intelligence will think like and I suspect it is pretty difficult to encode specific messages, the hardest perhaps being the message that prods the precipitants into reading your dammned message in the first place. Creating a fundamentally huge, glowing neon arrow telling the precipitants where to start might be as simple as creating unbelievably improbable arrangements of matter. As we look closer, we may find ever more statistically improbable arrangements, layered in a complex way.
  • Heh (Score:3, Interesting)

    by Moraelin (679338) on Friday August 31, 2007 @03:00AM (#20421613) Journal
    Heh. I didn't say that you could pick up the universe and run with it, like with a suitcase, or whatever you imagined there. The thing about flipping the suitcase was just a simple experiment to show that the complete system has an angular momentum even if just a part of it spins. I'm not saying someone could turn the whole universe. Just that it can have a non-zero total angular momentum, if all galaxies rotate the same way.
  • by Anonymous Coward on Friday August 31, 2007 @03:12AM (#20421661)
    Nonsense. Sure, scientific results rise and fall on their own merits, and blah blah, but an author's background is a perfectly acceptable initial filtering criterion. When the background is largely or entirely unrelated to the science being done, we don't go running to Slashdot, which was my entire point. Instead, we take a look over the work, and when we see that the author fails to address important issues, be they theoretical or practical, we don't go trumpeting the results to the masses.

    I deleted from my inbox today an email from someone who has disproven the Uncertainty Principle. Of course, I didn't discard it simply because it was sent to me unsolicited by someone in China with a non-academic address, because that would be unscientific. He could be right, and have overturned quantum mechanics, because science is a claim assessment tool, not a citation index. So I looked at the first paragraph, saw that he mistated both the definition and the meaning of the Uncertainty Principle, while making some dubious assertions about the nature of quantum mechanics, thus indicating that he doesn't actually understand the very thing he claims to disprove. Thus having examined the work on its own merits, I deleted the email, rather than running to submit it to Slashdot.

    I don't think at all that Dr. Longo is a crackpot. But his background raises flags, particularly when one has seen many of these advanced-career physicists who move over into astronomy and quickly make grand discoveries. Points (1) and (2) do not make me disbelieve his results. They do make me look at the actual work, which makes me disbelieve his results.

    Again, all three points I made are relevant to whether this kind of thing should be announced in places like this. All three should make someone look into the actual science, or ask someone who can, before plastering it on a highly-read website, where it will be taken as fact by those who don't (through no fault of their own) know better. That was my concern, not whether he should be ignored by the scientific community. And I know, I've now spent far, far longer on this than I would have by just ignoring these posts myself. But while I don't come to Slashdot to learn astronomy, I'd prefer that the people who do learn things here get real science and not the fringe.

    I am "capable" of doing what my high energy colleagues do, in the sense that I can write the programs they can and fit the models they do. I am not "qualified", however, to take a stack of semi-reduced data from one of them and get a believable answer, because I don't know the systematics and subtleties. I've no doubt that Dr. Longo is perfectly capable of understanding astrophysics at the level required to interpret results from the data, but he demonstratably does not understand the reduction of Sloan data, as pointed out by various commenters here. His results are therefore highly suspect. The fact that he doesn't want to get it reviewed only makes things worse.
  • Re:Why? (Score:3, Interesting)

    by bcmm (768152) on Friday August 31, 2007 @07:00AM (#20422631)
    Is it much easier to see galaxies which are aligned such that the observed area of the sky they cover is greater?

Contemptuous lights flashed flashed across the computer's console. -- Hitchhiker's Guide to the Galaxy

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