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"Dark Flow" Outside Observable Universe

Posted by samzenpus on from the here-comes-galactus dept.

DynaSoar writes "NASA astrophysicists have discovered what they claim is something outside the observable universe exerting an effect on the observable. The material is pulling clusters of galaxies towards a region of space known not to contain sufficient matter to create the effect. They can only speculate on what the material is and how space might differ there: 'In these regions, space-time might be very different, and likely doesn't contain stars and galaxies (which only formed because of the particular density pattern of mass in our bubble). It could include giant, massive structures much larger than anything in our own observable universe. These structures are what researchers suspect are tugging on the galaxy clusters, causing the dark flow.'"

101 of 583 comments (clear)

  1. Great! by incognito84 · · Score: 4, Funny

    Now I feel even smaller than I did yesterday. Good job, science!

    1. Re:Great! by oodaloop · · Score: 5, Funny

      Maybe you should get one of those pumps.

      --
      Tic-Tac-Toe, Global Thermonuclear War, and relationships all have the same winning move.
    2. Re:Great! by Hal_Porter · · Score: 2, Funny

      Medicine giveth and science taketh away.

      --
      echo -e 'global _start\n _start:\n mov eax, 2\n int 80h\n jmp _start' > a.asm; nasm a.asm -f elf; ld a.o -o a;
    3. Re:Great! by lysergic.acid · · Score: 5, Insightful

      i think it's kinda cool. the idea that there are even more massive structures out there than what's in our observable universe is really quite mind-boggling. but without stars and galaxies i wonder what kind of emergent structures or phenomena could exist beyond our observable bubble.

      i'm guessing it's probably not possible for biological life to form in such a radically different environment, but then again maybe i just lack the imagination to conceive of such possibilities. it seems like within our observable universe for any biological life to evolve it must follow certain patterns dictated by the laws of physics/chemistry. but if space-time in these regions is so different from our observable universe then who knows? our level of consciousness compared to what exists out there might be like comparing an amoeba with a blue whale. even the time scales experienced by other life forms could be drastically different from ours. entire civilizations could spring forth and flicker out of existence all in the blink of an eye.

      but since we can't even observe what is out there maybe this is all pointless speculation.

    4. Re:Great! by foobsr · · Score: 2, Funny

      maybe this is all pointless speculation (emphasis mine)

      As pointless as observing something outside the observable universe — thus, there is no need to worry.

      CC.

      --
      TaijiQuan (Huang, 5 loosenings)
    5. Re:Great! by AlecC · · Score: 3, Interesting

      I would agree that if there is life, it is certainly not life as we know it.

      But IMO the fundamental thing needed for life is an energy flow. Possibly you also need a state of matter corresponding to what we regard as solid i.e. one in which components tend to stay put without needing to expend energy. Given those two components, and enough time, I think that something that we could tentatively call life will emerge, occasionally, anywhere. How long it will take to get past the bacterial level is a much more complex question.

      --
      Consciousness is an illusion caused by an excess of self consciousness.
    6. Re:Great! by timmarhy · · Score: 4, Insightful

      i think life is possible in almost any kind of environment. just look at the so called fragile state of life as we know it - bacteria that thrives in nuclear reactors and in boiling water. from what i've obversed life isn't fragile OR rare, but tough enough to adapt to anything and populating to the extent it seems like a cosmic imperitive.

      --
      If you mod me down, I will become more powerful than you can imagine....
    7. Re:Great! by Eivind · · Score: 4, Insightful

      It's contradictory anyway. If we're seeing something influenced by it, then we ARE observing it. That's what observation MEAN.

      If you're "watching" something, you're really interpreting electrical signals generated by your retina in response to chemical reactions triggered by photons, nothing "direct" about it whatsoever.

      So saying we're seeing something being influenced by something outside the observable universe is nonsense.

    8. Re:Great! by Z00L00K · · Score: 3, Insightful

      Humans are insignificant for the terms of the universe, but we at least strive to understand it.

      We haven't yet fully understood the universe, and even if we do it's so large that it's hard to fathom the span of it.

      And did the universe really exist before the big bang or was it created by the big bang? How can one prove something that is hypothetical if we don't have something to measure it against?

      Anyway - it is possible that what attracts matter is nothing more than an inert part of matter - or more specific a black hole that currently is invisible because it has consumed all matter near itself a long time ago.

      The Big Bang wasn't a "perfect" explosion, and if it had been we wouldn't have had the distribution of galaxies that we have - it would have been a cloud of gas. And since we haven't had a perfect explosion it is possible that the black hole was created at a very early stage of our universe.

      But who knows in reality?

      --
      If builders built buildings the way programmers wrote programs, then the first woodpecker would destroy civilization.
    9. Re:Great! by Rand+Race · · Score: 2, Insightful

      ... bacteria that thrives in nuclear reactors and in boiling water.

      Most extremophiles are archaea rather than bacteria.

      --
      Insanity is the last line of defence for the master diplomat. But you have to lay the groundwork early.
    10. Re:Great! by BraksDad · · Score: 2, Insightful

      If God did create the universe he must exist beyond that universe and thus even bigger than the universe.

      Religion would thus make you feel even smaller.

      WOW, I am quite spiritual, I feel even smaller than you.

      --
      Slowly waving my hand - "This is not the sig you are looking for."
    11. Re:Great! by Kagura · · Score: 2, Informative

      The "influence" you are talking about travels at the speed of light, just like everything else in the universe. If we are in range of their influence, then we are in visual range. Read everybody else's posts, as they pretty much say the same thing as the poster you responded to.

    12. Re:Great! by AlecC · · Score: 2, Interesting

      To which all I can say is http://www.eastoftheweb.com/short-stories/UBooks/TheyMade.shtml

      --
      Consciousness is an illusion caused by an excess of self consciousness.
    13. Re:Great! by l0cust · · Score: 2

      You are absolutely right. I muddled up the analogy of a physical "horizon" with the way its used when talking about observable universe. I realized my mistake when I read through some of the other posts but /. doesn't have an "edit" function so.. :)

      --
      Politicians and Pedophiles: Two groups of exploitive bastards who are most dangerous when they're thinking of children.
  2. Re:Since looking farther = further in time by caffeinemessiah · · Score: 5, Informative

    Then are we also looking at near the time of the big bang?

    Since no one reads TFA anyway, and since you clearly didn't:

    The universe is thought to have formed about 13.7 billion years ago. So even if light started travelling toward us immediately after the Big Bang, the farthest it could ever get is 13.7 billion light-years in distance. There may be parts of the universe that are farther away (we can't know how big the whole universe is), but we can't see farther than light could travel over the entire age of the universe.

    And then:

    A theory called inflation posits that the universe we see is just a small bubble of space-time that got rapidly expanded after the Big Bang. There could be other parts of the cosmos beyond this bubble that we cannot see. In these regions, space-time might be very different, and likely doesn't contain stars and galaxies (which only formed because of the particular density pattern of mass in our bubble). It could include giant, massive structures much larger than anything in our own observable universe. These structures are what researchers suspect are tugging on the galaxy clusters, causing the dark flow.

    Finally, on a side note, years of watching slashdot paid off in a truly interesting story!

    --
    An old-timer with old-timey ideas.
  3. Are we alone? by Capsaicin · · Score: 4, Funny

    Years of watching slashdot paid off in a truly interesting story

    Yes and the editors missed the once-in-a-lifetime opportunity to run it under the heading "NASA SCIENTISTS DISCOVER GOD." Damn!

    --
    Better to be despised for too anxious apprehensions, than ruined by too confident a security. --Edmund Burke
    1. Re:Are we alone? by Chris+Rhodes · · Score: 5, Funny

      Cthulu waits.

  4. I'm no astronomer by Centurix · · Score: 5, Funny

    But I'd say if lots of really big things are being affected, then there could be a bigger thing out there.

    It's a theory I know. I'd like to call it Cen's Big Fucking Thing theory, it's a big ball of stuff, chairs, signs, tanks, gravel and so on, literally sucking the universe dry of interesting stuff. A universal suck, maybe even a multiversal suck mechanism. Either way, I'm pretty sure we'll not see it coming.

    --
    Task Mangler
    1. Re:I'm no astronomer by incognito84 · · Score: 3, Funny

      So it's essentially like a giant vacuum (cleaner)?

    2. Re:I'm no astronomer by Centurix · · Score: 3, Funny

      Yes, a big bagless vacuum cleaner. In my theory I'll outline to time of the apocalypse, or as I call it, Dyson time.

      --
      Task Mangler
  5. Flimflammery by MaxwellEdison · · Score: 5, Insightful

    I'm actually pretty excited at this news. Granted, my understanding of astrophysics is limited to Hawking books and guests of George Noory (kidding, kind of). But I look forward to anything that seems to pin down the concept of 'dark matter'.

    Dark matter to me has always smacked of a Victorian Era flimflam artist talking about the aether. And I don't care how dapper Mortimer T. Snerd is dressed, I'm not drinking his dark matter kool-aid until I can get a better explination for it than 'its invisible, supermassive, unobservable, and so totally there'. If you can't explain it to me, the interested layman, you may need to put your theory back in the crucible o' truth. Its probably not done yet.

    --
    -=Bang Bang=-
    1. Re:Flimflammery by RichiH · · Score: 2, Insightful

      'Can be understood by an interested layman' is definitely the wrong metric for measuring scientific advancement.

      That being said, the aether & dark matter/energy analogy is something I have been thinking about as well. It _does_ feel like a crutch for current theories. Or someone figures out where this stuff hides in the next 24 hours. Who knows :)

    2. Re:Flimflammery by Ambitwistor · · Score: 5, Interesting

      But I look forward to anything that seems to pin down the concept of 'dark matter'.

      This new theory isn't an alternative to dark matter.

      I'm not drinking his dark matter kool-aid until I can get a better explination for it than 'its invisible, supermassive, unobservable, and so totally there'.

      You believe neutrinos exist, right? How hard is it to believe that there's something else like a neutrino out there, but heavier?

      Dark matter-like particles have been predicted for decades. Within the Standard Model, there's the axion which is supposed to solve the strong CP problem in QCD. In the supersymmetric extension of the Standard Model, there is the neutralino. In fact, most theories beyond the Standard Model naturally require some heavy scalar particle which could be a dark matter candidate.

      Modifying gravity doesn't appear to consistently explain all the gravitational behavior we observe. The other alternative is modifying the source of gravity, i.e. there's something out there we can't see for some reason. And that does account for the gravitational behavior we observe.

    3. Re:Flimflammery by Abcd1234 · · Score: 2, Insightful

      Modifying gravity doesn't appear to consistently explain all the gravitational behavior we observe.

      In fact, it actually *can't*. Once again, I cite the Bullet Cluster and MACS J0025 results. As this researcher put it, "Nevertheless, the most straightforward interpretation is that there is indeed unseen mass.", and "It does add something new, and that is that whatever that mass is, it is not collisional." Incidentally, his position is that CDM is still not the answer, and that the real solution is a combination of MOND plus some sort of non-interacting mass (eg, WIMPs). But given whatever is there is a) invisible, and b) collisionless, that proves that there's *something* out there that qualifies as dark matter, even if you're unwilling to believe that it is the sole explanation for the missing mass problem.

      In summary: for those of you complaining that dark matter resembles aether: you're wrong. It exists. It's existence has been demonstrated in real results. No one credible is denying this fact any longer.

  6. Smelloscope by SlowMovingTarget · · Score: 3, Funny

    Somebody remind Professor Farnsworth not to point the smelloscope at the dark flow. He passed out last time.

  7. Gravity Leech by CuteSteveJobs · · Score: 5, Interesting

    > NASA astrophysicists have discovered what they claim is something outside the observable universe exerting an effect on the observable.

    The third episode of Brian Greene's "Elegant Universe" documentary miniseries on PBS said that while matter is confined to the known dimensions, its possible that gravity isn't and so can move through dimensions. The example they feel is that we could possibly detect the gravity of 'something' in another Universe by its gravity, even though we could never actually touch it. Wonder if this is it?
    http://www.pbs.org/wgbh/nova/elegant/

  8. In other news... by freedom_india · · Score: 5, Funny

    The Dark Matter in US is pulling a ball busting amount of money away from tax payers to Large Banks.
    In this area of Universe known as Capitol Hill and White House, the normal laws of space-time continumm is suspended so that banks which screw up your money get your money to bail out themselves.

    --
    "Doing what i can, with what i have." ~ Burt Gummer
  9. Re:The Universe goes on Forever by Big+Nothing · · Score: 4, Funny

    " If the known universe is expanding outward, that means that it has to have someplace to go, right?

    Or am I just high right now?"

    I'd say it's a little of both.

    --
    SIG: TAKE OFF EVERY 'CAPTAIN'!!
  10. Hmmmmm.... by paniq · · Score: 2, Funny

    I have a bad feeling about this.

    --
    Do not trust this signature.
    1. Re:Hmmmmm.... by paniq · · Score: 2, Funny

      Episode VIII: The Dark Flow

      For greater emotional effect, imagine the original post in yellow colored font, scrolling to the horizon in front of a panorama of stars. Add some John Williams fanfares while you are at it.

      --
      Do not trust this signature.
  11. The plot thickens by sleeponthemic · · Score: 3, Interesting

    Suddenly, the predicted "end of the universe" models look a little dusty.

    --
    I record my sleeptalking
  12. bah by buswolley · · Score: 2, Insightful
    A force you can't detect exerting force?

    The universe is mmuch more complex than the average scientist lets on.

    --

    A Good Troll is better than a Bad Human.

    1. Re:bah by MaxwellEdison · · Score: 5, Insightful

      Don't tell anyone, but when contrasting known information against an infinite cosmos...the average scientist is basically as clueless as the rest of us.

      --
      -=Bang Bang=-
    2. Re:bah by Culture20 · · Score: 2, Insightful

      Absolutely wrong. [...] A in philosophy, F in science.

      And PhD stands for Doctor of Philosophy. Science is examined at the philosophical level by those at the top, and they recognize that
      ( scientist~=layman <= Total Possible Knowledge )
      if they earned their Doctorates the hard way.

    3. Re:bah by earlymon · · Score: 2, Insightful

      Decades ago, university courses tying beliefs to science were given - I seem to recall one relating Zen Buddhism to physics.

      I think it's altruistic to believe that science is examined at the philosophical level by those at the top unless you could be more specific. I hobnob with a large number of Ph.D.s, majority physicists, definitely from best schools, definitely came up the hard way. Of those, and admittedly speaking from my experiences - but maintaining that is direct experience - the ones that map philosophical beliefs to science are in the minority.

      {soapbox}Extending to theosophy (adding religious beliefs to the philosophy and science soup) I personally opine that Hawking's, Galileo's, Newton's, and Einstein's formative thinking were adversely affected by philosophical contaminants. Taking the argument to the absurd to make the point (and substituting << as in much less than for your <= as in less than or equal to) relating to Total Possible Knowledge..... what scientist? what layman? computer scientist ~= astrology-or-creationist-believing layman << Total Possible Knowledge?? Yes, A << C and B << C making A and B somewhat analogous, but this doesn't make A ~= B.{/soapbox}

      I hear that there's a tombstone in Germany, and accepting this as fact, it's inscription is one of my favorites: "Now I know more than the wisest among you." This is a stunning and crystal clear truth for all things metaphysical.

      Some people want to study physics or cosmology to understand the mind of God, or the meaning of existence. I wish them best luck, as I was once one of them, and now believe that the grave will give the answer - (linear) time abides all. For that subset, you can argue your A~=B<=C case (no disrespect, but I prefer to save on typing), but you're really not arguing to cosmology.

      For those in group A that are interested in physical law for its own sake - to say that those in group A, who have worked their asses (and brains) off most all of their lives are equivalent in knowledge to those who have not, is simply not true. I'd have to allow the degrees of freedom that transmutes knowledge as wisdom or all knowledges as equivalent or transmute the properties of the equality (to political or existential equivalent or to equivalently ignorant for sufficiently large values of C (and given that C is by your definition, very significantly large)) to agree otherwise.

      Your A~=B<=C argument isn't at all new. In fact, it's very medieval. I don't much subscribe to it - just as I don't do well with angels dancing on pins, either, as it's the same discussion.

      I wasn't trolling anyone, and wasn't intending to waste bandwidth with my original post - I was just laying down a little dry humor and trying to open the door for membrane theory. If you look at the poster I'd responded to, and postulate (correctly) that I'd read his/her previous post and postulate that my reply was friendly (geez - my wife's friends are built, and there was an invitation to a pub there!) then maybe the context of what I'd written might seem different.

      However - your reply stand on its own merit, as I hope this one does for you.

      My instincts tell me that dark matter is a growth industry in physics and any truth in the matter may be long coming until the wheat is separated from the chaff. Is there a force in a true vacuum? A lot of the chaff came from Einstein's addition of a cosmological constant (added for religious/philosophical reasons - my theory says the universe is not steady state, I *know* it is steady state, I hereby add a cosmological constant to make it so) and others refuting Einstein when he said such a constant was his biggest blunder (no, Albert had the right idea, wrong constant!), sprinkle in calculation error regarding vacuum energy (i.e., dark energy), and there you are. Now comes the topic at hand, and my only point was - do we know the framework for the hypothesis in the article? Do we know the bent of those involved? Are they accepting strings as a corollary to membrane collision and positing spacetime laws in that regard?

      I'd like to know more. For all effects and purposes, I'm as clueless as a lay, man.

      --
      Pathological kinda promises Path + Logical - but instead, you get stuck with pathetic.
  13. Re:Sensationalist Much? by MaxwellEdison · · Score: 2, Funny

    Won't be long until astronomers discover the Odelay Nebulae. A cluster of three that resemble a microphone and a pair of turntables. The only question is 'Where its at?'.

    --
    -=Bang Bang=-
  14. ermmm... by dexmachina · · Score: 4, Interesting

    The speed of light is also the maximum speed of causation...if these "super structures" are outside the observable universe, how in the hell are they affecting anything within the observable universe? If they can exert causal influence on these galaxies, and the light from these galaxies has time to reach us... I could be wrong but I feel like someone, somewhere, is seriously contradicting themselves. Maybe those string theorists can tell us if its possible there's cosmic string tied between the galaxies and a giant tug boat in hyperspace...

    1. Re:ermmm... by TheLink · · Score: 4, Insightful

      You can't see ships past the YOUR horizon, but those ships could certainly see other ships that you can't see that are beyond YOUR horizon, but not theirs.

      --
    2. Re:ermmm... by dexmachina · · Score: 5, Insightful

      Yes I know, but we can see the galaxies travelling under the effect of this supposed dark flow. If we can see the galaxies being affected by these superstructures, then the light travelling to us from the galaxies which we now see left after the causal influence reached them, which means the causal influence had time to reach /us/. Which means the super structures aren't in the unobservable universe...

    3. Re:ermmm... by mcrbids · · Score: 3, Informative

      Yes but by the time those other ships were able to report to you the ships that they see that you can't, you can see those other ships, too.

      --
      I have no problem with your religion until you decide it's reason to deprive others of the truth.
    4. Re:ermmm... by aussie_a · · Score: 2, Interesting

      My understanding (and I'm most likely 100% wrong) is that imagine the Big Bang didn't create everything in the universe. Instead it just created everything we can see. There exists stuff beyond our eyesight that's existed since before the big bang. We can't see it because light from stars has yet to travel to it, bounce off it and then travel back to us.

      Like everything else in the universe, this invisible matter could still have mass which exerts a force much like stuff does within the visible universe.

      Why have we never seen it then? Well perhaps as everything in the visible universe expands, it also pushes back the stuff outside the visible universe.

      We can know one thing about this stuff though. It doesn't contain any stars for the simple reason that we would have seen the light travel from it.

      NOW this answers a question I've had for a very long time, which is "why did the big bang happen?" which would be "because the matter in the universe formed together tight enough and in such a way as to create the big bang" which means there could have been other big bangs in the universe which means we might one day (millenia from now) see light from another big bang.

      However it does raise yet another question "what created all the stuff that exists outside the visible universe?" and before someone says god I then ask "What created god?"

    5. Re:ermmm... by ByteSlicer · · Score: 5, Informative

      At cosmological scales, metric expansion of space becomes very important. Light that left 13.7 billion years ago will actually travel 47 billion lightyears because of metric expansion. Since metric expansion implies space-time is curved (at cosmological scales, locally it is flat, like the earth is flat locally), general relativity comes into play. This means the normal causality described by special relativity is no longer applicable.

      Imagine points A-B-C to be gravitationally bound. Because of metric expansion, space between A-B and B-C expands. This can cause A to move away from C at larger than lightspeed. Since space between B-C only expanded half of A--C, B will be withing light distance from C and thus visible by observers on C. Light from A can reach B, but it will never reach C. By the time it would, space between B and C will have expanded so much that observers from C will no longer see B.

    6. Re:ermmm... by Headw1nd · · Score: 3, Insightful

      This is why examples fail. There is no physical "horizon" like there would be on earth, the only "horizon" is time and the speed of light. To try to repair the ships example, the horizon would be expanding away at cannonball speed, thus when you see the first ship hit by a cannonball, you should logically bee able to see the ship that fired it at the same time, if not earlier. Thus if you see a ship hit by a cannonball, and don't see the ship that fired it, you might assume that the cannonball somehow travelled above cannonball speed. Or not, since this example isn't complete: The ocean is also expanding between you and the ships, and betwen the two other ships. To summerize, the naval analogy isn't really optimal for this problem.

    7. Re:ermmm... by Anonymous Coward · · Score: 3, Insightful

      Yep you're right, but *I think* they're talking about a different horizon to the one you're thinking of (the summary doesn't make this clear).

      The furthest back we can see is the CMBR, due to the Universe being opaque any earlier on. This opacity creates a horizon at a slightly shorter distance than the horizon you would get due to the fact that light/changes in gravity fields propagate at c.

      The abstract (linked below) mentions that they suspect it is gravitational influences from beyond the CMBR barrier (but before the speed of light barrier) that is producing the effect:

      "... and may be indicative of the tilt exerted across the entire current horizon by far-away pre-inflationary inhomogeneities." ... at least that's how I translate the above.

    8. Re:ermmm... by Randym · · Score: 2, Informative
      The speed of light is also the maximum speed of causation...if these "super structures" are outside the observable universe, how in the hell are they affecting anything within the observable universe? If they can exert causal influence on these galaxies, and the light from these galaxies has time to reach us... I could be wrong but I feel like someone, somewhere, is seriously contradicting themselves.

      Think of it like this: they *expect* to see a certain red-shift from something at 6 billion light-years: it is moving away from us, and the radiation that we receive from it is "red-shifted" by a well-known amount. What they are apparently seeing is *more red-shift than they expect* and the vector of this extra red-shift points toward a certain section of space. Thus, they are deducing that "something out there" is *pulling* that group of galaxies, and the only force (that we currently know of) that operates at that scale is gravity.

      Scientists are looking out past that group of galaxies at 6 billion light-years to *as far as they can see* (13.7 billion light-years), but they are not finding enough *matter* there to account for the gravitational action of this cluster of galaxies at 6 billion light-years. So whatever is pulling the galaxies is *beyond* 13.7 light-years.

      The problem is that we have assumed -- until now -- that *everything in the universe* is within our little bubble with a radius of 13.7 billion light-years. Now, apparently, we've discovered that *this is not the case*. Something ... else ... is out there.

      --
      DNA is a Turing machine. You, however, being dynamic and emergent, are not.
  15. Re:Since looking farther = further in time by Big+Nothing · · Score: 4, Interesting

    What bugs me is that this "bubble" of the known universe really isn't a bubble at all, it's just the physical limit of our ability to observe; we have no means of determining the extent of this "bubble". Therefore, claiming that there could be "giant, massive structures much larger than anything in our own observable universe" just outside this bubble seems somewhat... convenient.

    While I agree that this is one of the more interesting stories on slashdot in years, there are many aspects of contemporary cosmological theories that I remain highly skeptical of.

    --
    SIG: TAKE OFF EVERY 'CAPTAIN'!!
  16. William James Sidis by solferino · · Score: 2, Interesting

    Reminds me of some writing by William James Sidis, published in 1925.

    Our previous consideration on the production of radiant energy from the stars indicates that such production of radiant energy is only possible where the second law of thermodynamics is followed, that is, in a positive section of the universe. In a negative section of the universe the reverse process must take place; namely, space is full of radiant energy, presumably produced in the positive section of space, and the stars use this radiant energy to build up a higher level of heat. All radiant energy in that section of space would tend to be absorbed by the stars, which would thus constitute perfectly black bodies; and very little radiant energy would be produced in that section of space, but would mostly come from beyond the boundary surface. What little radiant energy would be produced in the negative section of space would be pseudo-teleologically directed only towards stars which have enough activity to absorb it, and no radiant energy, or almost none, would actually leave the negative section of space. The peculiarity of the boundary surface between the positive and negative sections of space, then, is, that practically all light that crosses it, crosses it in one direction, namely, from the positive side to the negative side. If we were on the positive side, as seems to be the case, then we could not see beyond such surface, though we might easily have gravitational or other evidence of bodies existing beyond that surface.

    Furthermore, just as in the positive section of space, light is given out uniformly in all directions, so, in the negative section, light must be absorbed by a star equally from all directions. Thus, to any star in the negative section, light must come in about the same amount from all directions; and, since most of this light comes from the positive sections, it follows that the negative sections must be completely surrounded by positive sections and must therefore be finite in all directions. By reversing this (since we have seen that all physical laws are reversible), it follows that any positive section must also be finite in all directions, and be completely surrounded by negative sections. We thus find the universe to be made up of a number of what we may call bricks, alternately positive and negative, all of approximately the same volume; a sort of three-dimensional checkerboard, the positive spaces counting as white (giving out light), and the negative spaces as black (absorbing light).

    Thus what we see is simply the white space that we are in. The surrounding black spaces are invisible, and in addition, absorb the light from the white spaces beyond, so that even those cannot be seen, and, if we judge from the distribution of light in the sky, we get an idea merely of the size and shape of our special white space.

    William James Sidis, The Animate and the Inanimate

  17. Preprint Versions of the Papers by Jazzer_Techie · · Score: 4, Informative

    There are preprints of the two relevant papers on astro-ph.

    More general version (ApJL)
    http://xxx.lanl.gov/abs/0809.3734

    More technical version (ApJ)
    http://xxx.lanl.gov/abs/0809.3733

    1. Re:Preprint Versions of the Papers by IHateEverybody · · Score: 3, Interesting

      Either I'm confused or the write up and author of the space.com article are just confusing. Granted, I'm not a physicist but it seems to me that the papers are saying something very different from the write up and the article say. Instead of some mysterious new force from outside the universe, the two papers are based on an analysis of the Cold Dark Matter theory which has been around for some time.

      The article is also confusing when it talks about the "known universe." The Inflationary Theory of the origin of the universe says that early on in its existence, the universe underwent a drastically fast expansion. When physicists talk about the "observable universe," they are referring to the idea that Inflation caused parts of the universe to expand so rapidly that their light cannot reach us in the age of the universe. Now those regions are still part of our universe, we just can't see them because they are "over the horizon" so to speak like a ship on the ocean which disappears from view once it gets so far away from shore that the Earth curves away from our field of vision.

      In fact this last point appears to be the most interesting part of the papers if I understand them correctly. The papers suggest that it is possible to peak over the horizon and get an idea of what the universe looks like beyond the limits of what we can see with our telescopes. Like the mast of a ship peaking out from the edge of the horizon, clusters of galaxies that we could not see otherwise can be detected by carefully measuring the effects of their gravity on regions of the universe that we can see.

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    2. Re:Preprint Versions of the Papers by Ambitwistor · · Score: 2, Interesting

      Instead of some mysterious new force from outside the universe, the two papers are based on an analysis of the Cold Dark Matter theory which has been around for some time.

      Read the papers again. The first paper doesn't mention dark matter at all: it's talking about "pre-inflationary remnants" outside our cosmological horizon (observable universe). The second paper is talking about the same thing, although it does mention dark matter (to note that other than the peculiar flow, the matter behaves according to the CDM model).

      Your description of the observable universe is right, but I don't think it conflicts with what the article says. You're also right about the last point: the authors are hoping that matter outside the other side of the observable universe has left its gravitational imprint on matter near the boundary.

  18. It's Obvious by LandDolphin · · Score: 4, Funny

    It's God

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  19. Wow, lets just add another hypothical entity by Anonymous Coward · · Score: 2, Insightful

    What NASA really meant to say was, "Shit, we just found something else that does not fit our current model of the universe. Lets just make some stuff up and call it a new discovery"

    Maybe this time people will wake up.....probably not.

    http://bigbangneverhappened.org/

    1. Re:Wow, lets just add another hypothical entity by Slashcrap · · Score: 4, Funny

      Seriously guys, the place is a red-taped bureaucracy waste. They're too busy running background checks on people in non-sensitive jobs to do research.

      This just screams, "I got fired from my NASA cleaning job for using meth".

  20. Re:Sensationalist Much? by calmofthestorm · · Score: 2, Insightful

    Dark + Science = We have no clue what's going on please fund us

    Disclosure: I'm a heavy advocate of funding the sciences and a scientist myself. But seriously guys, just admit it if you don't have a clue;)

    To put it from my freshman chem course:

    If someone talks about:
    Yuan-Teller distortion - 50% chance bullshit
    Second-Order Yuan-Teller distortion - 100% chance bullshit
    Pseudo-Second-Order Yuan-Teller distortion - You are being mocked.

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  21. I forgot to say..... by DynaSoar · · Score: 4, Informative

    I'd intended to add this to the summary, but forgot.

    TFA has a very nice, if brief, explication on the "universe" vs. "observable universe". Too many people (science and science writing pros among them) make assertions about the former when they should specify the latter.

    Go ahead and read it, it's only a space.com article (ie. very short).

    --
    "I may be synthetic, but I'm not stupid." -- Bishop 341-B
  22. It could be ANYTHING by Auckerman · · Score: 2, Insightful

    To paraphrase David Hume: There is no reason to believe that the laws of physics have always been what they are today at all points in space and at all points in time. While it is well within reason, and quite likely, that the Universe follows neat patterns quite specifically, when one runs into really odd data that doesn't fit into your tidy boxes it might be time to rethink things. Dark matter/flow/energy or whatever the new buzzwords scientists come up with are stop gap measures meant to really say, "we haven't the foggiest idea what's going on, but it doesn't quite add up".

    --

    Burn Hollywood Burn
  23. Re:Since looking farther = further in time by Plutonite · · Score: 4, Informative

    And there are aspects of many contemporary theories (and lesser recognized works) that are equally skeptical of, and orthogonal to, each other. I personally don't know enough GR to talk confidently about why this is not exciting, but if it does turn out to be exciting, expect some very well written and insightful roundups here:

    www.cosmicvariance.com

    Small note: I have found Sean Carrol's [and team] work on the internet to be some of the most accessible stuff available from brilliant minds in science today. Of course, every time you read something dumbed down mathematically (even if only slightly), you end up hating yourself for not spending the time instead on understanding the 3 years worth of adv.math courses you need to really grasp what is happening. But the upside is that you can spend 15 minutes reading some well written summary by people like these, and end up getting a fairly good idea of the issue at hand all the same. Kudos to science "bloggers" (esp world-leading academics) everywhere. You make the internet suck a lot less.

  24. Re:Since looking farther = further in time by oldhack · · Score: 4, Insightful

    If we are observing far-away galaxies being affected by the stuff too far away for us to observe directly, maybe we are observing the stuff outside our bubble indirectly? This visibility can be transitive?

    Also, maybe we can also "observe" the stuff outside our bubble via the effects of "spooky action at a distance"?

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  25. Re:woot by calmofthestorm · · Score: 2, Insightful

    fail.

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    93rd rule of Slashdot: No matter how obvious my sarcasm is, my comment will be taken seriously by someone.
  26. Re:THE PINK SOCK by MrNaz · · Score: 2, Funny

    Slashdot, vous échouez Unicode.

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  27. Does this imply FTL? by Excelcia · · Score: 3, Interesting

    Ok, here's a question for you. The "observable universe" isn't just the observable universe for us, it is that for the whole universe. Nowhere in the universe that is observable to us can you go and observe beyond 13.7 billion light years. We're all in the same boat. However, in the area of the universe that is being affected by this phenomena, they must be able to observe what is causing it. Elsewise, it couldn't be affecting them. There is nothing that can affect me that is unobservable. You can't be so far away that you are beyond my observation range and yet still affect me, unless you are exerting FTL influence on me. So, if this is truly an influence from beyond the visible universe, then that would seem to me to imply FTL.

    1. Re:Does this imply FTL? by ThomsonsPier · · Score: 2, Insightful

      No.

      Anything outside our observable universe cannot affect us without FTL velocities being involved. The observable universe, however, is centred on whatever is doing the observing. Therefore, things we can see from here have their own observable universe and, thus, their own set of stuff by which they can be affected.

      Poor ananlogy: imagine you can see a cat sitting on a street corner. It disappears around the corner because it can see some tuna. You can't see the tuna and are therefore unaffected by it (let's assume that you can't smell it either), but it's apparent to the cat.

    2. Re:Does this imply FTL? by Crookdotter · · Score: 2, Informative

      I don't think that's right. If the tuna effect reached the cat, and the cat has relayed that information to us, then the tuna's effect should also have reached us in parallel.

    3. Re:Does this imply FTL? by 49152 · · Score: 3, Interesting

      True.

      However the radius of the observable universe increases with time.

      The time it took for light to travel from these distant galaxies should equal the additional time it will take for light from the cause of the movement to travel from the galaxies to us.

      This means that if we can see the action we should also be able to see the cause.

      Information cannot travel faster than light neither directly nor indirectly.

      The only explanation I can see is that this speed (or flow) was caused by a gravitational tug that happened around the time of inflation.

      But if this is the case we should not register any current (or rather at the time we see now light departed from the galaxies toward us) acceleration of these distant galaxies apart from what can be expected from the general expansion of the universe.

  28. Re:Since looking farther = further in time by Antique+Geekmeister · · Score: 2, Interesting

    No, our universe could be a black hole. In that case, the boundary or "bubble" has a much stronger meaning, and it could make more sense to talk about material 'outside' our universe.

  29. Re:Since looking farther = further in time by roguetrick · · Score: 2, Insightful

    I would like to counterpoint that I don't believe in your mind, and this post was never posted. It just was.

    --
    -The world would be a better place if everyone had a hoverboard
  30. Re:The Universe goes on Forever by The+Master+Control+P · · Score: 4, Insightful

    Your reasoning is trapped by trying to imagine the universe as some defined boundary expanding. It's the same reasoning that images the Big Bang as an explosion in space.

    The bang wasn't an explosion in spacetime, it was an explosion of spacetime. The expansion of space just means that the metric which measures distance between two points that stay at the same location changes. As time passes, two points which stay at the same location on some hypothetical reference grid will first measure one foot apart, then two, then five, etc. They aren't going anywhere, they're being carried along on space itself.

  31. Re:Since looking farther = further in time by rts008 · · Score: 3, Informative

    "Also, maybe we can also "observe" the stuff outside our bubble via the effects of "spooky action at a distance"?"

    Well, then when we 'observe' this stuff, WE will have on our conscience whether the cat is dead or alive.
    But we still may never find out which one; which bubble^Wbox was/is in? :-)

    All joking aside, this is very interesting data to work with.
    I can imagine a lot of theories to change/be scrapped/ be rewritten here in the near future.

    I am really excited about this! (but somewhat befuddled-[I am not a physicist, much less an astrophysicist!]Astrophysics is a serious hobby for me) I hope some good info comes with further research.
    That should open new 'doorways' and expand our understanding.

    I don't think I can imagine all of the ramifications of this, but it strikes me as: 'Holy Cow, Batman...that cow lit her fart and flew over the moon!!!'

    No doubt, this is the most exciting thing to happen with astrophysics (for me) in the past several years. The questions are ENDLESS!!!!!

    Who knows 'what doors will open' for us, and the potential to find out what possible uses could arise from this.

    P.S. I wish I knew enough to actually correctly answer your questions, but this news seems to sprout far more questions than can be accurately answered at this time.

    Oh, and BTW, my head asplodes!!

    --
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  32. Super.... by Xelios · · Score: 2, Insightful

    First we had dark energy, then dark matter, now dark flow. All to try and explain an unexpected effect of something we don't understand. Lets figure out what exactly gravity is and how it really works over large scales, then we can revisit all this "dark" stuff.

    --
    Murphey's fighting Occam, and we're in the stands.
  33. Doesn't make much sense to me by CTachyon · · Score: 4, Interesting

    Let's start with a recap of some statements that are true under current physical theories: (1) space itself is expanding (Hubble Expansion); (2) early in the history of the universe, the expansion of space was faster than the speed of light (Inflationary Big Bang theory); (3) nothing can exceed the speed of light, not even gravity or information (Special and General Relativity); and (4) we are confined our "observable universe": a bubble 92 billion light-years in diameter (General Relativity plus Inflationary Big Bang theory — 13.7 billion light-years, plus inflation, plus 13.7 billion years of Hubble expansion).

    Given these facts, neither gravity nor information from outside our observable universe can enter it.

    Sure, parts of what we currently consider the observable universe might, in their own relativistic timeline, be "currently" experiencing a gravitational tug from parts of the universe that we can't currently observe, even in principle. However, if that is true, then either (a) such observable places will exit our field of observation before we observe that gravitational tug (i.e. the universe will expand faster than light), or (b) such unobservable places exerting a gravitational tug will enter our field of observation before we see the tug on things we can currently see (i.e. the universe will expand slower than light).

    There's no way that information could take a roundabout path to us and arrive faster than information traveling in a straight line (or, more correctly in GR, a geodesic). Think about it: if light/gravity/information cannot travel directly to us, because the direct path is too long and too slow, how could it travel indirectly to us? The indirect path is, by definition, longer and slower than the direct path.

    I suppose that, if a large mass was once observable but now is not (i.e. it tugged on some galaxies, then inflation happened), the theory in the article might make a certain amount of sense. But the timescale of inflation (fractions of a second after the Big Bang) doesn't really leave a lot of time for that to happen. It sounds much more plausible to my ears that either (a) there is a previously-undiscovered conglomeration of dark matter in that direction, but it still lies within our observable bubble; or (b) the galaxies in question are at high velocity but no longer accelerating, indicating leftover momentum from an ejection, collision, or some other high-energy event in the early universe.

    OTOH, I'm no physicist, so maybe I'm missing something, or maybe the actual theory being promoted makes more sense than Space.com's rather awful writeup.

    --
    Range Voting: preference intensity matters
    1. Re:Doesn't make much sense to me by Karma+Bandit · · Score: 4, Informative

      You should read the abstracts of the articles, since it turns out you're right. From the abstract:

      "This flow is difficult to explain by gravitational evolution within the framework of the concordance LCDM model and may be indicative of the tilt exerted across the entire current horizon by far-away pre-inflationary inhomogeneities."

      They would, at least, find it less plausible to describe it with a huge mass of dark matter.

    2. Re:Doesn't make much sense to me by Ambitwistor · · Score: 2, Informative

      I suppose that, if a large mass was once observable but now is not (i.e. it tugged on some galaxies, then inflation happened), the theory in the article might make a certain amount of sense.

      Yes, that's the idea here: the distant galaxies are still experiencing left-over motion due to a tug from matter long ago, which has by now expanded beyond our ability to see. This is a feature of the accelerating expansion due to inflation. Objects which were once within our causal horizon can be far, far away from it now. All we see is what effects remain from when they were near us.

      But the timescale of inflation (fractions of a second after the Big Bang) doesn't really leave a lot of time for that to happen.

      There was time for objects to gravitationally influence each other, if they were very close. Then they got blown far apart by the extremely rapid inflation. That's the whole point of inflationary theory: that objects used to be able to interact with each other (explaining the homogeneity and isotropy of the universe), but now they can't.

      It sounds much more plausible to my ears that either (a) there is a previously-undiscovered conglomeration of dark matter in that direction, but it still lies within our observable bubble;

      The authors claim the velocity is too large to explain this way.

      the galaxies in question are at high velocity but no longer accelerating, indicating leftover momentum from an ejection, collision, or some other high-energy event in the early universe.

      They're too far apart to all be affected by a single cosmic event, unless it was in the very early universe when they were very close together (i.e., pre-inflation). That's what this theory proposes. The idea is that this all happened before there were galaxies or even atoms, just a plasma of high energy particles. During inflation some particles got tugged more in one direction than another if different regions of space were inflating at different rates, giving them a peculiar velocity relative to the average Hubble flow. After inflation, atoms, gas, stars, galaxies, etc. condensed from them, retaining the primordial peculiar velocity.

  34. Re:Since looking farther = further in time by AngelofDeath-02 · · Score: 2, Interesting

    To my knowledge, this isn't possible because nothing can travel faster than the speed of light.

    To expand on that, Information cannot travel faster than the speed of light either, which means neither can gravitational forces, or ... well, anything else we're aware of.

    Unless of course, you're implying that our limit of perception isn't the limit of the speed of light, but something else.

    --
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  35. Re:The Universe goes on Forever by Thiez · · Score: 2, Insightful

    Would you mind explaining why? The big bang theory does not in any way suggest that we are 'special', and it is not in contradiction with any observations as far as I know.

  36. Re:Silly trend in science by budgenator · · Score: 2, Interesting

    I think what is happening is the universe as we know it is a blackhole, basically light gets redshifted to a frequency of 0 eventually, that is an event horizon and has a radius of Hubble's constant / c; the effect is caused structures that are inside the galaxies observable universe, they are 6 Billion light years away, so they can see 6 Billion Light years farther than we can, but are outside our observable universe. Because it is unobservable it is dark to us.

    --
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  37. Re:Since looking farther = further in time by jacquesm · · Score: 3, Funny

    by definition, expansion of space is Imperial, not metric.

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  38. I think you're misinterpreting... by warrax_666 · · Score: 4, Informative

    the word "observable". AFAIUI, in this case it means directly observable. Given an expanding universe -- since nothing can travel faster than light (and c is finite) and the universe has a finite age there is a limit to how far you can "see" in any direction from any given vantage point (see "horizon problem"). However, you might still be able to see an object at the very edge of "your" observable universe being influenced by something beyond your particular observation horizon -- that is, you can tell that it is being influenced by something and that it's not being influenced by something inside horizon. So essentially very talking about indirect observation here.

    --
    HAND.
    1. Re:I think you're misinterpreting... by orkysoft · · Score: 2, Informative

      Would that object influencing the observed object not need to be inside your light cone for you to even observe the influencing that it is doing?

      --

      I suffer from attention surplus disorder.
    2. Re:I think you're misinterpreting... by orkysoft · · Score: 3, Informative

      Your analogy is flawed, since speed of light does not play a role in it, while it does with this observable-object-influenced-by-object-outside-our-lightcone situation. For the information about the unobservable object to be able to travel to us, it must be within our lightcone, otherwise it would entail information travelling faster than light.

      --

      I suffer from attention surplus disorder.
    3. Re:I think you're misinterpreting... by CrimsonAvenger · · Score: 4, Informative

      Would that object influencing the observed object not need to be inside your light cone for you to even observe the influencing that it is doing?

      No, it wouldn't. All that is necessary is that the influenced object be inside the light cone of the influencing object

      Yes, it would. Gravity works at lightspeed also, so any gravitic effect on an observable object must be detectable at the observer, making the influencing object "observable".

      Likewise, any other effect that we know of, all of which are limited to lightspeed. The only way that something outside the observable universe could affect something inside the observable universe and be seen by something else inside the observable universe is if the laws of physics that we know and love are basically a steaming pile of horse apples.

      --

      "I do not agree with what you say, but I will defend to the death your right to say it"
    4. Re:I think you're misinterpreting... by CrimsonAvenger · · Score: 2, Informative

      From my understanding, if those galaxy clusters are moving with c/2 in one direction and we are moving with c/2 the other way, the galaxy clusters are at our horizon (total speed of separation c). But while they are approaching the outside object fast, gravitational pull would be faster, and we could see the measured trajectories.

      According to our current understanding of physics, the situation you describe can't actually occur. It is impossible for two pieces of matter to be moving apart at c. If we were moving at c/2 in one direction, RELATIVE to some piece of matter, and yet another piece of matter were moving at c/2 away from that reference matter in the opposite direction, that second piece of matter would be observed as moving away from us at 0.866c, and be well within our "observable universe".

      Even if we assumed your case were valid, then we'd have to assume that the gravity from the object outside the observable universe (hereinafter the THING) could reach that far-flung galaxy (hereinafter, OVERTHERE), interact with it, and then the light from OVERTHERE could come here, and beat the light/gravity effects from the THING here, even though all of them (light/gravity from the THING, light/gravity from OVERTHERE) are moving at c. Can't happen unless something is moving ftl. In which case, we're back to using words like "quaint"....

      --

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    5. Re:I think you're misinterpreting... by camperdave · · Score: 2, Insightful

      Yes, it would. Gravity works at lightspeed also, so any gravitic effect on an observable object must be detectable at the observer, making the influencing object "observable".

      Well, let's set aside for a moment the fact that we have not yet measured the speed of gravity accurately enough to tell if it is equal, above, or below the speed of light. We'll just assume it's equal.

      Now that I've given it some post coffee thought, you are, of course, correct. My error was that I was considering the light cones of transmitting influence both from the "unobservable" object, and from Earth. I was looking at the wrong half of the light cone.

      --
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    6. Re:I think you're misinterpreting... by 49152 · · Score: 3, Informative

      That is wrong I am afraid.

      Nothing and that includes information can travel above the speed of light neither directly nor indirectly.

      Yes, it it possible for something at the edge of our observable universe to be affected by something outside our observable universe right now.

      But we do not (and cannot) observe what happens at the edge right now, but rather when light left that place heading in our direction a very long time ago.

      So in effect we are seeing what happened at the edge in the past. This also means that the light from anything capable of affecting that part of the universe at that time would also by now had time to reach us and so we would be able to see it.

      The summary is (as usual) a bit misleading.

      What the article is suggesting is not that something outside the observable universe is affecting something else inside it right now and that we can see the effect but not the cause, but rather that something influenced a part of the universe around the time of the great inflation shortly after the big bang.

      At that time those parts of the universe would have been close enough together that they could have affected each other. The inflation stage which was an extremely fast expansion of time and space itself has since moved some parts (in fact probably most of it) outside our observable universe so we cannot see this part.

      What they see is something having a great speed due to an earlier influence by something we cannot see now, not that it is still being accelerated because that would have been a violation of the speed of light.

      I hope I am not to unclear on this but English is not my first language so I find it a bit hard to explain any clearer.

    7. Re:I think you're misinterpreting... by orkysoft · · Score: 2, Informative

      If we see an object A (which is by definition inside our light cone) being influenced by another object B that we cannot observe, B is in our lightcone, but just occluded, because if it were outside our lightcone, it could not possibly have been observed, directly or indirectly.

      See the other branch of this thread.

      --

      I suffer from attention surplus disorder.
    8. Re:I think you're misinterpreting... by Ambitwistor · · Score: 3, Informative

      Both of those are assumptions. If they were true, there wouldn't be a logical explaination for tachyons.

      Who cares if there's a logical explanation for tachyons, since we don't have evidence for any?

      Anyway, even if tachyons existed you'd never actually observe anything traveling faster than light; see this FAQ.

      In other dimensions things DO move faster then light.

      Says who? In any relativistic quantum field theory or string theory, c is the limit in any dimension.

      Furthermore, the speed of gravity is much greater then c.

      van Flandern's website is a bunch of crackpot nonsense. He was pretty notorious on Usenet for years. He misapplies perturbation theory; if you apply his same arguments to electromagnetism, you "conclude" that light travels faster than light too (see here). In fact, you can rigorously prove in general relativity that the speed of gravity cannot exceed c (see here, assuming that the gravitational waves aren't produced by weird things like negative mass). The 1993 Nobel prize in physics was awarded, in part, for an observational determination of the speed of gravity. (You can deduce it by the rate at which gravitational energy is radiated by orbiting bodies.) The measurements indicate that the speed of gravity is c, to within a few percent accuracy.

    9. Re:I think you're misinterpreting... by CrimsonAvenger · · Score: 3, Informative

      Why is this wrong?

      Because gravity works at the speed of light.

      If gravity from B left there at some time in the past, and reached A, it then continued past A toward O.

      Light from A went from A to O.

      Light and gravity move at the same speed, so, the light from A reaches us at the same time as the gravity from B.

      Therefore, B is within the "observable universe".

      In order for the above to not work, some part of the process above must include "faster than light". Which, so far as current physics is concerned, isn't part of the picture.

      --

      "I do not agree with what you say, but I will defend to the death your right to say it"
    10. Re:I think you're misinterpreting... by Ambitwistor · · Score: 2, Interesting

      If the speed of gravity is equal to the speed of light, no measurement no matter how precise will ever tell us if the former is equal, above, or below the latter. The error bars will always include above c and below c, even if they're incredibly small.

      Our indirect measurements indicate that the speed of gravity is the speed of light, to within about 1% accuracy.

  39. Re:Since looking farther = further in time by Ambitwistor · · Score: 4, Informative

    we have no means of determining the extent of this "bubble".

    Effectively, we can: we can't see past the surface of last scattering where the cosmic microwave background radiation originates.

    Therefore, claiming that there could be "giant, massive structures much larger than anything in our own observable universe" just outside this bubble seems somewhat... convenient.

    Well, the chaotic inflationary theory has long predicted such structures should exist at all scales outside the observable universe. Anyway, we see matter near the boundary of the observable universe. There are almost certainly large structures outside the boundary too. We see some of that matter moving in a way it ordinarily wouldn't according to the usual cosmological expansion. It's not that big a leap to hypothesize that it's being pulled by something on the other side of what we can observe.

    It's not a small leap, either — obviously it's hard to compile statistics on how these boundary clusters are moving, and thereby infer anything really solid about possible unseen gravitational sources. But it's not completely ad hoc. The explanation involves something that has been suggested by theory in the past for independent reasons, and observationally there don't appear to be any nearby sources of matter that could explain why the motion is so far from the Hubble flow. I suppose you could postulate a bunch of dark matter right near the boundary, but since (as you say) the cosmological horizon isn't some special physical place, but is just the region beyond which light hasn't reached us, that would be weird.

    This should be taken with the usual grain of salt: it's a brand new paper and in a year or two could potentially be explained in a much more mundane way. I'd personally give it less than a 50% chance of being right. But it's not a priori ridiculous either. As another poster said, I hope that Cosmic Variance covers the result ... a real expert second opinion would be valuable.

  40. Not new by elfguy · · Score: 2, Funny

    This is not new and has even been filmed before:

    http://www.youtube.com/watch?v=LyzIau5dBao

  41. Here Be Dragons by 4D6963 · · Score: 3, Insightful

    Therefore, claiming that there could be "giant, massive structures much larger than anything in our own observable universe" just outside this bubble seems somewhat... convenient.

    "giant, massive structures much larger than anything in our own observable universe" is the new "here be dragons".

    --
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  42. Re:Punk science by oldspewey · · Score: 4, Funny

    Fuck Off Matter

    You know, I've been wondering for a long time just exactly what is the secret ingredient in a tall, cool glass of Shut the Fuck Up.

    --
    If libertarians are so opposed to effective government, why don't they all move to Somalia?
  43. Re:Since looking farther = further in time by gtall · · Score: 2, Funny

    Turtles all the way down...clearly.

    Gerry

  44. Re:Silly trend in science by oldspewey · · Score: 2, Funny

    Whoa ...
    [/KeanuReeves]

    --
    If libertarians are so opposed to effective government, why don't they all move to Somalia?
  45. Re:insufficient data by Ambitwistor · · Score: 3, Insightful

    First, the region that these clusters are supposedly moving towards are pretty close to being in line with the heart of the Milky Way. What this means is that the attractor object may simply be obscured by our own galaxy.

    It's not just the lack of an attractor object, it's the unusual velocities.

    Second, the motion is not unusually large for superclusters.

    They argue otherwise: "If produced by gravitational instability within the concordance LambdaCDM model, the motion would require the local Universe out to ~ 300h^1 Mpc to be atypical at the level of many standard deviations of the model", and argue that even a 100 km/sec motion due to local gravitation alone would be excluded by observations. I confess that I don't know enough cosmology to understand why. Either you expect smaller motions in the earlier universe or else there are additional constraints at work (they mention having to explain why the dipole is approximately constant with depth). I'd have to do more background reading to understand what's going on here, but the point is that they say they have reason to believe that the motion is unusually large.

    What really bothers me here is the claim that these bodies are still experiencing forces from the long departed rest of the universe.

    I don't think they are. From my reading of the paper, it sounds like this motion is left over from the inflationary phase.

  46. Re:Different Universes (norse mythology) by MightyYar · · Score: 2, Funny

    Once I did that 3 times in a row

    You're a WITCH!

    --
    W..w..W - Willy Waterloo washes Warren Wiggins who is washing Waldo Woo.
  47. Re:which space? between galaxies or atoms? by meringuoid · · Score: 4, Informative
    Does that mean the size of an apple gets larger? or the distance between two apples gets larger? What is it the atom radius? or the distance between galaxies?

    What is happening is that the underlying geometry of space is expanding. Best estimate of the rate of expansion is something like 72 kilometres per second per megaparsec. So if two objects are one million parsecs apart (that's 3.26 million lightyears), then one second later they'll be one million parsecs and 72 kilometres apart.

    In addition, objects in that space are free to move within it, and so if they are subject to mechanical forces they'll follow those forces just as normal. So atoms and apples are held together by their internal electromagnetism, and the Solar System by the gravitational attraction between the Sun and the planets. Objects like these drift along with cosmic expansion, but do not themselves expand.

    It's only on the cosmic scale that the universal expansion becomes significant. Remember, we're talking kilometres per second per megaparsec - on such a huge scale, forces pulling objects together drop to tiny levels, while the expansion of space becomes greater and greater. The Andromeda Galaxy is only two-thirds of a megaparsec away, and so the cosmic expansion is small compared to the local motion of the galaxies - indeed, we're on a collision course with Andromeda. The largest known object in the Universe, the Great Wall, is maybe a hundred times more distant; on this scale, the cosmic expansion becomes significant. It's really the distance between galactic clusters and superclusters which is being expanded.

    --
    Real Daleks don't climb stairs - they level the building.
  48. Re:But distances CAN increase quicker by 49152 · · Score: 2, Informative

    As someone else pointed out this is exactly what the article is talking about.

    Something influenced these galaxies around the time of inflation to give them a very high speed. Since then inflation has moved that something outside our observable universe (or lightcone if you will).

    But what I was answering to was the claim that someone somehow was able to see something being influenced by something else outside our observable universe. I fail to see how this could be correct even considering inflation or the continuous expansion of time-space itself.

    BTW: The article does not actually claim that anything outside our observable universe is still affecting these galaxies, only that something must have done at some time.

    The article says that these far away galaxies are being observed to have an unexplained velocity not an unexplained acceleration.

    The cause and effect took place a long time ago and that part of space time is probably not inside our observable universe anymore.

  49. Re:But... by Ambitwistor · · Score: 2, Informative

    There are huge comment threads here arguing over the same question.

    The answer is that their gravitational fields do not now have any effect on our observable universe. They used to. Pre-inflation, they could gravitationally influence us, and we could see them too. (Or we could, except for the fact that the universe was opaque back then.) Now we can't, because they expanded too far away.

  50. Stupid stalker by wurp · · Score: 2, Informative

    Is someone following me around modding my stuff overrated? I wouldn't have minded if they had actually modded the factual parent post to which I referred up, or the incorrect ancestor +5 post down. As it is, they're just hiding the truth.

    CrimsonAvenger, modded at 2 (the parent in my MOD PARENT UP comment), has it completely right. Warrax, modded at 5 Informative, has it completely wrong.

    "Information can't travel faster than the speed of light" means just what it says. The impossibility of detecting changes outside your light cone is transitive - you can't detect changes outside your light cone, not even in the form of detecting changes to an object inside your light cone caused by an object outside your light cone.

    At least, per relativity, you can't. If you can, then relativity is wrong.

  51. Re:Silly trend in science by Kagura · · Score: 2, Informative

    the effect is caused by structures that are inside the galaxies observable universe, they are 6 Billion light years away, so they can see 6 Billion Light years farther than we can, but are outside our observable universe.

    Sounds like you don't quite understand the concept of a light cone... Let me simplify your example and see if I understand you:

    *Galaxy A is within the Milky Way's observable universe.
    *Galaxy B is outside the Milky Way's observable universe, but it's within Galaxy A's observable universe.

    You are suggesting that even though we can't see Galaxy B, Galaxy B is still acting upon Galaxy A, and that we are seeing its perturbations here on Earth.

    However, that doesn't work in an expanding universe. If Galaxy B is already past our observation horizon and continuing to recede, we will never see its effects on Galaxy A from our vantage point in the Milky Way.

    You can read more on this fascinating topic at http://en.wikipedia.org/wiki/Observable_universe, and it's far better written there than I could ever hope to personally explain.

  52. God's address by idlehanz · · Score: 2, Interesting

    Now we know where He lives.

    --
    Changing the world... one research project at a time.