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Astronomers Discover a Group of Quasars 4 Billion Light Years Across

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  • by Anonymous Coward on Saturday January 12, 2013 @01:45PM (#42568395)
    What exactly makes this "a structure"? All linked gravitationally or what?
    • by History's Coming To (1059484) on Saturday January 12, 2013 @01:56PM (#42568475) Journal
      From the sounds of it this is a case of proximity rather than being gravitationally bound:

      Since 1982 it has been know that quasars tend to group together in clumps or ‘structures’ of surprisingly large sizes, forming large quasar groups or LQGs.

      Most things in space tend to cluster together - dust around stars forms planets, stars group together in galaxies, there's a hierarchy of galactic clusters and super clusters, and some of the largest scale structures can contain tens of thousands of galaxies. These large scale structures aren't caused by gravity pulling galaxies together, it's more of an inbuild clustering effect which originates in slight density fluctuations in the very early universe.

      • by girlintraining (1395911) on Saturday January 12, 2013 @02:37PM (#42568747)

        I think what people are missing is the laws of probability. When Einstein said it looked the same in every direction, what he meant was that it's all governed by the same laws. There's no local variations in the laws of physics. But the probability of something is never either 1 or 0, but some value in between, which means that if you do it enough times (observe) you're eventually going to stumble across something highly improbable. It does not mean that the universe still isn't mostly homogenous -- it just means that there are local defects, in the same way that when you're stirring pudding every now and then you get a lump in it.

        I don't find this find to be particularly interesting by itself. Science starts with "That's odd" more often than not, and this certainly is odd, but it doesn't prove anything. Not yet.

        • by TapeCutter (624760) on Saturday January 12, 2013 @07:18PM (#42570691) Journal

          When Einstein said it looked the same in every direction, what he meant was that it's all governed by the same laws.

          Actually it's more than that, it's also about the distribution of matter and energy on a large scale. It's assumed that matter is homogenous throughout the universe, homogenous literally means "no lumps" (above a certain size defined as "local" in your post). It's like an ideal gas, at the microscopic level you have all sorts of random "pressure" (kinetic energy of the individual atoms), at the macroscopic level there is just one pressure that is the same no matter what part of the gas you measure. This is because the macroscopic measurements are an average of all the individual microscopic pressures, the central limit theorem of statistics says that that the average of a big enough sample from a large population will always be very close to the real population average.

          In other words the reason it's "odd" is that statistics says the observation can't be brushed aside as a fluke, if the distribution of quasars is lumpy then either the basic assumption of large scale homogeneity is wrong, or the observation is flawed. The OP's stupid question is by far the most insightful thing I've read about it so far, how are they defining the word "structure".

          • by MaskedSlacker (911878) on Saturday January 12, 2013 @07:35PM (#42570775)

            homogenous literally means "no lumps"

            No, it literally means "same kind". Homo genos, the Greek words for 'same' and 'kind or type.'

          • It's assumed that matter is homogenous throughout the universe, homogenous literally means "no lumps"

            Homogenous doesn't mean exempt from the laws of probability. Even though the size of this is massive, this "lump" has only been observed once. Everywhere else you look in the sky conforms to the existing understanding and expectation of the uniformity of the universe. The central limit theorem hasn't been broken -- it may however require a redefinition of what "local" is. There's all kinds of weird one-offs that we've observed -- things that seem highly unlikely (certain celestial configurations of orbiting

          • It strikes me that, if the universe was *infinite* in all directions, it would look the same in all directions.

            If the universe is finite in size, as it seems to be, surely there would be little chance it would, on average, look the same in all directions?

    • Descriptive entropy (Score:5, Interesting)

      by Okian Warrior (537106) on Saturday January 12, 2013 @02:28PM (#42568707) Homepage Journal

      Consider all the entities [stars, galaxies, or whatnot] in your study as points in 3-space. The descriptive length of the data is the total number of bits that describes the location of all points in your study.

      If all points are random and evenly distributed, then the total number of bits required is (number of points)x(number of bits for 1 location).

      Suppose you notice a clumping of points. Is this a structure or random variation?

      Rework your data description as follows: for any point, use the first bit to determine whether a point is a member of the clump or not, and subsequent bits to complete the description, depending on whether the point is in the clump.

      For this description, the total number of bits required is 1x(total number of points) + (number of points in clump)x(number of bits for location relative to clump) + (number of points not in clump)x(number of bits for general location).

      If the 2nd description is shorter than the 1st description, then by Occam's razor the second description is more likely correct.

      In fact, the number of bits directly tells the probability that the 2nd description is correct: if the 2nd description requires 10 fewer bits (total) than the 1st, then the 2nd description is more likely to be correct by a factor of 1024. Alternately, there is a 1/1024 chance that the 2nd description is *not* the correct description of the data.

      If you have lots of data, it's not unusual for a descriptive length to be thousands of bits shorter than the baseline description; meaning, that it's virtually certain that the new description is correct and that the new structure does not arise from random variation.

      I haven't seen the data, but I assume that describing all galaxies in the universe using the newly described "clump" as a categorical structure gives a smaller descriptive entropy than describing all galaxies without the extra category of "clump".

      • by icebike (68054)

        Assigning some numbering system to perceived localized concentrations in a random universe is sort of like throwing more money in a Vegas Slot Machine on the theory that some supposed law of averages suggests you are bound to start winning any minute now.

        Clumps of anything in a random universe are not rare.

        It seem just as likely that the clump is simply a term used by astronomers to refer to that group we were talking about during coffee break.
        The word "structure" seems a bit of a stretch here, when you con

        • by fatphil (181876)
          > Assigning some numbering system to perceived localized concentrations in a random universe is sort of like throwing more money in a Vegas Slot Machine on the theory that some supposed law of averages suggests you are bound to start winning any minute now.

          It's hard to tell if that's wrong, or just meaningless. It parses as English, but it doesn't seem to actually be countering the post to which you responded. I'll try to mimic you:
          "Claiming clumps in a random universe aren't rare is sort of like pouring
      • by AnilJ (1342025)
        In other words, is it the size of this clump which causes the excitement?
    • by Anonymous Coward

      What makes the molecules that is your body different to the molecules in the "air" or "walls" around you?

      For a long time scientists has tried to make the universe simple:
      From stars in the heavens to just a bunch of galaxies spread around.
      Then it was superclusters, and so and and so on.
      Now the scale is broken again, and the old assumptions will need to be revised again.

      In the end, we'll probably have to accept there is no limit to the universe, and at NO scale is _everything_ homogenous.
      It makes things more

  • Andromeda is perpendicular to the visible sky from Earth. This new collection of galaxies is parallel to the visible sky from Earth.

    Using one as a reference point for the other in four-dimensional space makes little sense to me.

    • by wonkey_monkey (2592601) on Saturday January 12, 2013 @02:15PM (#42568615) Homepage
      The new collection is four billion light years long. Andromeda is 2.5 million light years away. This means the collection is 1600 times the distance to Andromeda in length. What's wrong with that? (apart from the fact that either distance is pretty close to unimaginable for us day-to-day Earth-bound humans)

      Using one as a reference point for the other in four-dimensional space makes little sense to me.

      It's being used as a reference distance.

    • by icebike (68054)

      Andromeda is perpendicular to the visible sky from Earth. This new collection of galaxies is parallel to the visible sky from Earth.

      The concept of parallel makes no sense when referring the the "visible sky" which is roughly a half sphere, and a half sphere that varies according to one's position on the earth. The geocentric model of the universe has fallen into disfavor recently. You may want to consider some more modern conceptual models.

      • by Meyaht (2729603)
        Hold a paper plate out at arms length in a way that you can only see the edge of it. Now imagine its "crazy" far away and"holy shit" big. That's what they're saying, except its not a plate, its WHAT WE ARE TRYING TO DISCUSS WHILE YOU ARE BEING.... kindof a dick.
  • by Anonymous Coward

    Really... now that we know the Universe has a 'rough' alignment, which is giving the theoreticians fits, is this quasar structure aligned with the so-called Cosmic Axis of Evil?

  • by Anonymous Coward

    I tend to disagree with the assumption the article makes that this really disputes Einstein's cosmological theory. It just indicates that the large-scale sameness he calculated is at much larger scales - the observable universe turns out to be a tiny part of a much larger reality.

    So, now we know we know less than we thought. This seems to be a trend :D

    • Well, the more you know, the more you know you don't know.

    • by Patch86 (1465427)

      If the "sameness" holds, presumably this pattern of clustered quasars should have similar relations in other parts of the sky.

      (IANAPh)

      My understanding of the concept of cosmological sameness is that you pick any patch of sky and the contents should be more or less the same- the same material content, the same patterns (or lack of patterns), etc. If there are corners of the universe which are substantially different from other corners, then that implies that our theories governing the early universe (which s

      • by Agent0013 (828350)

        If the "sameness" holds, presumably this pattern of clustered quasars should have similar relations in other parts of the sky.

        (IANAPh)

        My understanding of the concept of cosmological sameness is that you pick any patch of sky and the contents should be more or less the same- the same material content, the same patterns (or lack of patterns), etc. /p>

        And I would imagine that the fractal geometry we see in seashores and tree branches holds at the larger scale of the universe also. So the sameness holds not only for the different parts of the sky, but for different scales of the sky. So when a smaller section of the sky is looked at, we see clumps. People assumed that those would disappear when viewed at a larger scale, but I don't see why the clumpiness wouldn't hold at larger scales also. This only makes the universe more the same everywhere you look.

  • Big (Score:5, Interesting)

    by PPH (736903) on Saturday January 12, 2013 @02:16PM (#42568625)

    Based on the map in the linked article, it appears that this Quasar has an angular diameter of about 10 degrees. The moon is about 0.5 degrees. So if the magnitude was high enough to be visible, this structure would be the size of a constellation. Of course, if it was that bright, it would have fried most of the observable universe.

  • by Anonymous Coward

    Heaven is for Real!

  • Come on, UCLan? Really, a quasar [eso.org] is 4 Gly long?
    • Okay, what I meant was: what has a single quasar got to do with all this? It was not an appropriate image to use in this context.
  • by AbrasiveCat (999190) on Saturday January 12, 2013 @02:42PM (#42568769)
    Wouldn't it be interesting if we could see the same structure in a different direction! Then we would know we could see to the end of the universe.
  • inflation ok here? (Score:4, Interesting)

    by vistapwns (1103935) on Saturday January 12, 2013 @02:47PM (#42568805)
    Curious question for you physicists or arm-chair physicists, does this have any implications for inflation? I've read here and there that inflation would be problematic if there were large structures in the universe, because nothing would have had time to propagate the distance in the time required to be compatible with inflation, so does this bump up against that limit or break it?
    • Re: (Score:2, Informative)

      by Anonymous Coward

      I think that would depend a lot more on the exact definition of "structure" used by astronomer and the causal connection between the parts of the structure. If the structure were more of just a coincidence, a bunch of stuff that happens to line up, it would mean no change to inflation or the scales previous found for homogenization of structure in the universe. And given the nature of stuff in the universe to form around kind a foam shape, it wouldn't surprise me that you could find long strings where it

    • by Anonymous Coward

      A lot of recent discoveries are breaking down General Relativity. Just too much you can't explain without getting rid of the whole no faster than light junk you've always heard. We astronomers wish the physicists would just leave our shit alone. Look up Superluminal Motion sometime. You can't get anything recognized or published unless you bend it to Einstein's will.

    • by ljw1004 (764174)

      I heard kind of the opposite: the large-scale structures now (e.g. superclusters, membranes, ...) are remnants of tiny quantum fluctuations early on in the big bang. If these fluctuations were early enough, then inflation will make them huge.

    • by bjorniac (836863) on Saturday January 12, 2013 @06:52PM (#42570491)

      It's a good question. I think you've gotten things a little backwards, though, with regars to the problem of propagation - inflation is a proposed explanation for propagation in the sense that it allows otherwise separate regions of the sky to have been in causal contact in the past. But this certainly does have impact upon the current inflationary paradigm in the following sense:

      If there were large structures or large inhomogeneities in the early universe (before inflation) then it would be hard to get inflation going. The basic models of inflation contain a field whose energy can be decomposed (and I'm playing very fast and loose here) into three parts: Potential, Kinetic and fluctuations. From these parts, we say that if the potential is large enough, the inflaton undergoes a "slow roll" down the potential during which our regular inflation happens. Fluctuations are treated as perturbations on this background, and it's from these that we expect to see the everyday structure in the universe. A warning though: We don't know the physics that causes these fluctuations to stop being quantum fluctuations and become classical perturbations in matter on this background.

      Now, if the fluctuations are too big, this model breaks down - the inflaton can't be high enough up its potential, and so slow roll can't happen. Hence before inflation we have to assume that the universe is largely homogeneous and isotropic, and fluctuations begin very small (technically in the "Bunch-Davies vacuum state).

      A big inhomogeneity AFTER inflation isn't too bad - it could well be that this is just the result of one of the longer wavelength fluctuations. Of course, one would then have to explain /why/ this wave in particular had such a large amplitude, but this really doesn't contravene inflationary models, it merely adds a new question about the initial conditions.

      Now, if we had been dealing with a serious overdensity (tons of quasars in the same spot) rather than a large strung-out structure, we would certainly have a problem with inflation, but so far as I know this isn't too big of an issue.

      Disclaimer: I work on the mathematical structure end of things, not the computation or observation, so there are certainly people more qualified than I, to whom I would happily defer if they want to post!

      • Ah, yes that's what I was kind of (clumsily) trying to get at, thanks for the great informative post, that's exactly what I wanted to know and I know that kind of answer does not come easy. :)
  • by Braintrust (449843) on Saturday January 12, 2013 @03:31PM (#42569155)

    All this observation really implies is that the true and full size of the universe is much larger than what has been documented so far.

    Currently, we can observe a bubble of space around us to a radius of about 13.5 billion light years. That's as far as we can see. This may well be analogous to being at the center of a water balloon, submerged in a swimming pool of much greater volume.

    We can currently see to the inner surface of that balloon, but the far greater mass of water outside of it remains hidden for now to our instrumentation.

    Complex systems will always tend to appear homogenous, given enough subjective distance.

    Fun fact: The rotational period of the Milky Way is approximately 200-250 million years.

    The universe we currently observe is approximately 13.5 billion years old --- there is no way a spiral of such definition could form after only 50-odd rotations, and yet still be so topographically distinct from other such bodies.

    That's simply not enough time.

    2c

    • by ath1901 (1570281)

      Fortunately, there are scientists studying these things. Here is a simulation of the formation of the milky way (it took 8 months to create it).
      http://youtu.be/VQBzdcFkB7w [youtu.be]

      So, way. A spiral of such definition can be created in 13.5 billion years.

      • by Reziac (43301) *

        Amazing. Who knew it took so long to flush the cosmic toilet? ;)

      • by fatphil (181876)
        That looked more like a simulation lasting more than 200 times the rotation rate of an outer spiral arm of the final galaxy, not 50.

        And why was there a constant stream of galaxies flinging themselves in our general direction? I thought the universe was expanding, so things should be thinning out?
    • What force? That's the difficult question here, and the problem with your argument (an argument from ignorance). Of the four fundamental forces in nature, gravity has the longest range. But, structures larger than a supercluster are too large for gravity, because the metric expansion of the universe is a stronger "force" at that scale or larger, and necessarily tears apart any larger structures. That implies larger structures must have formed in process of the Big Bang.

      The only known mechanism for creatin

    • But if you keep zooming out then they break apart again. They complex systems are fractal.

      This supports super symmetry.

      But none-the-less until we zoom out one set of the fractal we just don't know and cannot say for sure. This puts allot of doubt on the cosmological principle. It is also not the only thing that does so, as pointed out by the article.

      Anyway its really nice to see good articles posted to /. in this regard. This is a gem of one for me.

    • by Anonymous Coward

      https://en.wikipedia.org/wiki/Observable_universe#Misconceptions

      We can observe around 46 billion light years. It's way more complicated then just the speed of light when you add expansion.

      Other then that, yea, the universe is probably huge beyond reason and unknownable because of speed of light issues.

    • All this observation really implies is that the true and full size of the universe is much larger than what has been documented so far.

      There is no reason to believe the universe would just stop at its observable boundaries. The Big Bang theory implies that our observable universe once was many magnitudes smaller. It is often depicted as a point expanding to a sphere, but in reality it was a certain volume of which each point expanded to its own sphere.

      A galaxy near the border of our universe will be at the center of its own expanding observable universe, and see galaxies that we can never see.

      We can currently see to the inner surface of that balloon, but the far greater mass of water outside of it remains hidden for now to our instrumentation.

      Not only for now, but forever. Signals from out

  • Wow...that's a lot of televisions. [youtube.com]

    (Whenever I hear about "Quasars", I always mentally add in "...by Motorola." Yes, I'm that old...)

    • by Lije Baley (88936)

      They were sold to Matsushita not too long after that, and slowly merged with, and were augmented by the Panasonic line over the following 30 years. My father, and later myself, sold and serviced the Quasar line for almost that entire period. On the whole, they were good performing, reliable equipment at a good value. Matsushita brought some interesting technology as well, such as early RGB monitors and teletext units, the "Great time machine" VX video recorders which preceded VHS and Beta in the U.S., ch

  • If the universe is infinite then how would this single structure challenge the principle of the universe being same in every direction... Observable universe is in any case rather small take of the totality.

  • Original paper: http://mnras.oxfordjournals.org/content/early/2013/01/07/mnras.sts497.full.pdf+html [oxfordjournals.org]

    A pity that original submitter didn't include original research paper.

    Are we talking billion=10^9 or 10^12 ? It depends on the country of origin of researchers. http://en.wikipedia.org/wiki/Long_scale [wikipedia.org]
    So I checked in the original paper, and it is 1240 Mpc=4.04*10^9 ly, so it is 4 billions ly on short scale. BTW, I hate that we have two different scales - billion is ambigious.
  • In fact, the biggest cosmic structure ever seen is the universe itself. Obviously.
  • by Zorpheus (857617) on Saturday January 12, 2013 @05:02PM (#42569771)
    With a redshift of 1.3 this quasar group is probably close to the edge of the observable universe. What we see is from a time maybe some million years after the big bang. But at this time the universe was much smaller, so these quasars were much closer together than they are now. They are flying away from us since then into slightly different directions, and flying away from each other.
    What I think this means is: We can not calculate the size of this group from the angular diameter and its distance, it has nothing to do with reality. The angular diameter comes from different directions that the individual quasars are flying away from us, not from actually being this large. We can only see this quasar group as it was billion years ago, and at that time it was much smaller. We don't know what it looks like now. Also our perception of the form of this group would be distorted if the directions that its components are flying is not just caused by a homogeneous expansion of the universe.
    • by Zorpheus (857617)
      I mean this group can not be larger than a few light years since the universe had a size of only a few million light years at the time where we see these quasars.
  • by rossdee (243626) on Saturday January 12, 2013 @05:05PM (#42569795)

    If you look at something that is very far away, you may see 'structures' that look like they are associated, but in fact it just looks that way to you, and some parts of it may be a lot closer than others. A good example of this is the so called constellations, which civilizations in the past identified as animal shapes, but in reality the stars forming them were in no way related, and once astronomers were able to detirmine the actual distance to some of the stars they found that some were much further away.
    How far away (and long ago) is this 'group' of quasars? maybe its so far away (and long ago) that the universe hasn't expanded much, and we are seeing most of it.
    Maybe our line of sight is being distorted by the gravity of the black holes involved.

    Maybe its part of a giant sign (being constructed by the Magrateans) that says "This way to MilliWays"

    I need to get some sleep.

  • At the moment we don't even know what exactly are we measuring. Yes we might measure distance in terms of time taken by light to cover it but then what is time ? The concept of Scale might not be as easy to understand as it appears. A whole (alternate ? Micro ?) universe might actually exist inside a bacteria crawling under the tip of my fingers as I write this ? Can you prove that it doesn't ?
  • My question is; what affect did the expansion of the universe have on this "structure" over the 4 billion years that the light from them have been traveling to our little corner of the universe. It would seem to me that when that light originated the galaxys producing it should have been quite bit closer together. By my reconing, the distance between them would have been reduced by a factor of 4. Thus, the really would only span a distance equal to 5% of the width of the universe. Please, someone with more

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