Mysterious "Dark Flow" Is Tugging Galaxies Beyond the Universe's Horizon

By Eliza Strickland | September 25, 2008 5:40 pm

galaxy clusterIn a bizarre finding that has disrupted the current understanding of the universe, astronomers have detected evidence of a massive gravitational force beyond the horizon of the observable universe. What’s being called a dark flow appears to be pulling vast clusters of galaxies toward a 20-degree-wide patch of sky between the constellations of Centaurus and Vela. “It does fly in the face of everything we know,” said astronomer Dale Kocevski…. “I’m sure it’s going to be controversial” [Discovery News].

When scientists talk about the observable universe, they don’t just mean as far out as the eye, or even the most powerful telescope, can see. In fact there’s a fundamental limit to how much of the universe we could ever observe, no matter how advanced our visual instruments. 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 [].

In the surprising new study, which will be published in a forthcoming issue of Astrophysical Journal Letters [subscription required], astronomers looked at enormous clusters of galaxies that contain very hot, X-ray emitting gases. After researchers located these clusters, they looked at the same spots on a map of what’s called the cosmic microwave background — the attenuated glow from the first light that was free to travel through space just 380,000 years after the universe was born. This glow was mapped in detail by NASA’s Wilkinson Microwave Anisotropy Probe [Discovery News]. Astronomers believed that the microwaves change temperature when they pass through galactic clusters that are moving relative to the background glow, and they wanted to test that hypothesis.

Researchers expected to find some movement, but not much. Instead, the velocity of these clusters was computed to be around 2 million miles per hour [Ars Technica], and the galactic clusters were found to be moving in a coherent direction. Researchers say that the distribution of matter in the observable universe cannot account for this strong pull, meaning that there must be something truly massive over the horizon that’s tugging the galaxies in its direction.

And what might that something be? Lead researcher Alexander Kashlinsky suggests that there may be regions of the space beyond the observable universe that had a very different experience after the Big Bang. A theory called inflation suggests that our universe went through a brief period of hyper expansion soon after the Big Bang. It explains how matter managed to spread out so evenly in space, rather than get stuck clumped in just one corner of space, as would happen in a more gradually expanding universe. Inflation moves everything apart faster than gravity could clump it. It could be, then, that there was another, less effective inflation next door to our observable universe and that other blob from the Big Bang remained clumpier. If so it could be out there, loaded with matter, and it is exerting a powerful gravitational pull on every observable thing in our universe [Discovery News].

Go much deeper into this strange cosmic phenomenon with the Bad Astronomer’s latest post, “Trans-cosmic flow broadens our horizon.”

Image: NASA/STScI/Magellan/U.Arizona/D.Clowe et al.

CATEGORIZED UNDER: Physics & Math, Space
  • Laurie

    Could it be that there is another “universe” , just beyond the fringe of our universe ? Maybe it had a big bang of it’s own, or perhaps the inhabitants there believe in the steady state theory. Since it had a creation of it’s own, It might be may up mostly of anti-particles . Or, it might be made up of just energy or trillions of trillions of black holes. Perhaps the sum of all these universes really is infinite in every way. It might even be a collapsing universe close to converging back to another big bang.

  • Rosa

    you mean, a “big bang of its own….” and “a creation of its own.”

  • Dave

    Maybe inflation didn’t just expand the universe as much as it simply turned it inside out.

  • Todd

    Maybe, the fabric of the universe simply tore.

    What if the Universe was much like the inside of a jet plane in flight. What if the air inside the plane represented the fabric of space, and loose paper and debris represented matter, then during flight a window suddenly opened.

    Maybe the galactic clusters are rushing to fill one of several possible holes within the Universe. What if the fabric of space can only stretch so far before it tears? Could that have led to the rapid inflation of the Universe in the first place?

  • http://? dan

    Maybe, just maybe the God of scripture is real. So no matter how small we look or how big we look God is already there waiting for science to catch up. “The heavens reveal the glory of God” & ” Creation reveals what God is all about”.

  • noah

    Dan is right. Why can’t science look at the possibility that there is a CREATOR. Two “big bangs”? Ludicrous! To say there were two “miracles” of life coming from nothing requires faith in something other than a God. Why not give Almighty God the due credit? From the infinitesimal to the incredible vastness of space we see order, not chaos as an uncontrolled big bang would create. Yes, Dan said it when quoting from the Word of God that the “heavens reveal God’s glory”.

  • John

    Once again, as the unknown becomes a bit scary, we want to paint a human face on it and call it “God.”

  • D4devil

    Universe hasnt’en yet undrstood by us,evn successful theories lyk,RELATIVITY,BIGBANG,needs some modifications,…
    Can bigbang theory tell from where the SUPERATOM,that existd b4 bigbang came frm???
    Its just dat v mst nt accpt all succesful n allovr accptd theories as 100% corrct.N nw,v r gettng some observations n clues that theories cnt xplain sumthng,
    n plz ,dnt evn try 2 thnk bout so calld GOD,it cnt exist,if it doz,plz do giv me a scientific xplanation from where doz dis guy(GOD),came frm…

  • D4devil

    Hey,john is ryt,noah,wat makes u thnk dat gods waitin?N 4 wat?2 surprise us?
    oh,bt m sorry,bt no1’l gt dat sort of surprise,if god is there,n v cn prove its existnce xperimentally,thn,he 2 is binded by all physicals laws…N thn,he isnt a God
    if any1 thnks dat der is god,do tell evry1 hw he mst b,wat he mst b,of wat he mst b made of n where i cn find hm,atlist,a hint…Plz try 2 do dat,

  • Nathan Rockwell

    I have suspected an idea that I like to refer to as the Exponential Popcorn Universe. It is relatively simple to visualize… Assume a balloon (of massive weight and density…e.g. quasar) is spinning into a gradually increasing vacuum. As the vacuum increases, the force in on the matter within the balloon (from the shell of rubber) will slowly decrease. Since the balloon is spinning, the centrifugal force would push most of the matter toward the equator. Finally, the balloon pops, spewing matter out in all directions with decreasing speed from the edge of the x-axis in to the origin, and with decreasing speeds from the origin to North or South (this explains the red shift). The matter on the equator would leave at much greater speeds (and would be far greater in mass) than the matter in the inner radii.

    Step two… as the matter at the edge of the Universe reaches further and further into the increasing vacuum of deep space, the process either repeats itself, or begins to feel the gravitation of another object from outside of our own universe (possibly a quasar from our sister universe; the product of a big bang from our mother universe.) The two objects that have contacted one another through gravitational waves will begin to accelerate more rapidly toward one another, until they finally collide and either explode (big bang type two) or collapse upon one another. The matter that did not expand rapidly enough to escape mother universe either experienced a cold death or fell back upon itself (I lean more towards the cold death because of the implication of a red shift.)

    So again, more simplified, close your eyes and imagine (not to scale) a basketball spinning in place and exploding into billions of pieces. Some of those pieces go very far from the center and group into clusters the size of pool balls (approx 100,000 of them) which in turn, also explode into billions of pieces which [repeat] (100,000 x 100,000) hence exponential popcorn universe.

    This is not to say that there is no God. I am neither an astrophysicist nor a theologian, these are just my interpretations. God made the heavens and the Earth. He did not tell us the exact workings of either. To deny the possibility that God knows more than we can see only points a glaring finger back at Nicolaus Copernicus and Galileo Galilei, and the way the church reacted to it. If anything, the infinitely complex and unknown aspects of our universe and space beyond, only reinforces the idea of something greater.

  • http://? dan

    I am not afraid of scientific inquiry. I think God wants mankind to learn as much as possable. The article says though that the information we need to learn more about this dark flow will never reach us. This is creation revealing the nature of God. You see no matter how much of the wonders of our God we experiance there is an infinite amount of his wonder for us to still learn. Can’t see no fear in that.

  • Julian

    Couldn’t there be life in this other universe? And couldn’t that life have created a time machine and traveled back in time coming in contact with themselves and thus tearing a hole in the fabric of space and time? Maybe that hole is what is pulling on everything else.

  • Pixie of key

    Dark flow phenomenon causing force drawing someone truly massive property is located in the visible universe outside? How does this tractive force is conveyed?

    For example, the stars radiate throughout the energy of waves with particles of nature! Particles moving mode, which is already in place and at the same time, the region can move particles emanating from the various starfish, and they continue the movement quite the same direction away from the area in which the stars is!

    The visible universe outside is truly massive concentration of energy which radiate energy waves, which have the nature of quasars. the same region can become the galaxy from several different angles, so that the business continues to quite the same direction, at the same time, when the first stars emit flammable Light. As a dark flow phenomenon can be explained logically!

  • edward balcsik

    It would seem that if we are observing the impact of gravity from beyond the so called “observable universe” then we are observing things outside the “observable universe.” Does not this contradict the very concept of an “observable universe” beyond which we can not see?

  • Tuco

    Art is the absence of science, So why are the greatest works of art reside in the chapels of our fair planet.

  • Frank Gerbi

    We humans observe and theorize about the universe in our limited capacity is constrained by our 5 senses. Our visible universe is composed of physical substances, so no matter how vast it is, it has finite dimensions and must end at a certain point; this leads to the big question; what is there after that? we will never have an answer to that question if we continue to analyze the quandry in terms of our known physical sciences. It is my strong belief that the basic building blocks of the universe are a transformation of another form of existence in a different dimension completely invisibe and impenetrable by living humans. Actually there is no end to the universe, at a certain point matter in the universe is sucked into an invisible dimension
    ( it could be through black holes or another portal ) and spewed back again into our known universe’s physical forms, therefor creating a revolving door phenomenon with endless space. Everythin that exists in the physical universe has an orbital and cyclical motion pattern without any exception that I know of. The principle of a higher being “Creator” is vital to make what I am saying plausible.

  • B P Singh

    Yes, I agree with Frank Gerbi as he says “Our visible universe is composed of physical substances, so no matter how vast it is, it has finite dimensions and must end at a certain point; this leads to the big question; what is there after that? “. What has been explained till now is what we could see or think. Notbeyond that.

    But should we surender ourselves? Is it infinity ? but what is it ? Are we on continuam ? If yes, then till what will it continue?
    When we are unable to find answer we take shelter of Big Creator God/Ishwar / Allah.

    The GOD/ Ishwar / Allah all are belief. Human being’s belief. If he can’t answer he surenders to God/ Ishwar/ Allah. Do other animal too think so?
    Then what ?

    Can the Scientists/ Astrophysists / Philosphers of the univese resolve this? Is it real mysrty or we can’t think off?

  • Matthew Weflen

    Man oh man, Internet commenters.

    Perhaps dark flow is caused by all the additional free-floating apostrophes and spelling mistakes in online comments. A grammar singularity?

  • Frank Gerbi

    We are shakled by our physical boundries, we can not comperhend the universe as long as we are bound to our “PHYSICAL REALITY”; we have to develop our etherial nature which is eternal and ever evolving. Laws of physics are valid only in a very narrow band of vibrations which are evident to our five senses, they barely scratch the surface of what is realy out there. Actually what we call reality is not reality at all, its an illusion.

  • Nick Lingi

    Dan & Noah. Is this the same God that Christians accredit “miracles” to when something goes their way (like narrowly avoiding a car accident), but lets 20,000 children die a day from a disease that basically bleeds your internal organs….
    I’m an ex-Christian but I now denounce all religions after realising that they are responsible for all the evil, wars, greed, ignornace…..well pretty much everything bad in the world.

  • DanH

    Sorry, my education is probably lacking too much for me to make theories about what the “Dark Flow” is or means. Do you mind if I restate what I did understand in this article? Then someone can point out where I misunderstood things.

    So what I got from this article is that the period of inflation right after the Big Bang might possibly have pushed matter further away than the light from it has had time to travel to us here on Earth. So the 13.7 billion light-year limit isn’t really some sort of physical “edge” to reality, but rather just the limit of visibility- Like comparing driving on a foggy road at night to driving the same road on a clear day. The foggy night is the visible universe, and the clear day is all the universe- visible and beyond. So it sounds like the article is saying that we’ve just discovered that the universe is a whole lot bigger than what we are able to see. And the “Dark Flow” is affecting distant parts of the universe that we *can* see from beyond the distance that light has had time to get to us from way out there. Naturally, gravity attracts things that are close more strongly than it attracts things that are distant. So out there on the limits of visibility there is a greater effect on the matter that’s been found to be moving so fast. I guess someone good at math could calculate how much mass has to be out past our visibility limit- if there’s a number for the original rate of expansion, the amount of mass that’s been accelerated, and how far past our visible range the “Dark Flow” producing mass is located, etc. I can’t do that math, but if most of those numbers are known, then the rest ought to be able to be worked out.

    OK, that’s what I understood. Now where did I jump the shark? What did I misunderstand?

    Thanks for your time.

  • Nick S

    Nick Lingi,
    I understand your frustation and deal with it myself, but you must realize that “evil, wars, greed, ignornace…..well pretty much everything bad in the world” is the outcome of human actions, not God’s. We are given the choice to do right. Everyone in the world could drop what they are doing and help people in any situation, but do we? Just a counterpoint to your argument, worth considering.

  • yas

    hi heloo

  • lyllyth

    the Sun was born
    and so it shall die
    so only shadows comfort me
    I know in Darkness
    I will find you
    giving up inside like me

    (vnv nation)

    I keep waiting for Science AND Religion to catch up to the thought that dark matter quite possibly is the energy that IS the consciousness that makes up gods, life forms, everything else. It is the Source. It is intelligent. It is far bigger and smarter and more beautiful than our little animal bodies and brains can comprehend. It is the inner light that we cannot see unless we strip our minds of our egos, and stop seeking answers only externally. The Light that we cannot see only seems Dark to our eyes. It is made of Love, Laughter, and Transformation; the only three things that are “permanent” in the Universe. All else is consciousness playing with itself for the sheer joy of it.

    On the material level, I do think it makes sense that there is an inflow and outflow to the matter from our universe into “other universes” and back. Everything else is cyclical, so why not? I have often wondered, if there are black holes, where are the “white cones”?

    I am not arguing from scientific semantics, I don’t wish to try. But someday we will have to let go of Newton – or advance his concepts along with Einstein’s – to the next progression of understanding, which will likely look like nothing we are expecting.

    I hope I get to see it in my lifetime.

  • lyllyth

    Nathan, I like your Exponential Popcorn Universe theory. Fits right in with how I see it, too.

  • kilke


    The sad thing is, kids think typing like this is cool. The don’t even know how to spell the correct words.

    If things in the universe are all cyclical, why is it expanding. Does this mean it will contract eventually, or is the expansion infinite. Is something being created out of nothing? Maybe the dark matter/energy; whatever is being created is somehow tied to the passage of time. If you were to make each second a pancake, then stack each new second on top of the old, then the stack would grow infinitely. Looking at the universe from one dimension higher than our current 4D view, time all happens at once right? Since all of time exists at the same time, maybe all of past time is somehow represented as dark matter, and the reason it’s dark is because it doesn’t really exist now anymore.

    Well, that’s kind of the idea that is trying to come from my brain, but it’s harder to put the idea into words, especially with the hurdle of ignorance.

    Our consciousness may need to be factored into the universal equation someday too. Maybe what everyone thinks of as “God” is really the internal consciousness of higher understanding that can’t penetrate the current plain of existence, and until we bridge to that part of ourselves, we won’t understand the universe fully.

  • Axenome

    I think that a deific explanation is a cop out. Just say it’s “The hand of God” and poof. Explained. Now move on to something else.
    Takes all the responsibility away from us to figure out what’s going on.
    If we followed that logic, we’d still live in caves, worshipping the sun and stealing fire from dead trees struck by the “hammers of the Gods” aka lightning strikes.
    If God exists, and He/She/It truly made the entirety of the universe, that deity is utterly uncaring of the fate, behavior, or even existance of humanity. The most amazing, fascinating, awesome thing ever performed by any creature to have walked our planet wouldn’t have even rated an “oh, look at that,” from such a being.
    Believing that such a deity would actually notice us, or demand worship from us? The absolute pinnacle of human ego and undeserved self importance.

  • Doug Watts


    That’s what I got from this, Dan. There’s basically two limits to maximum visibility in the Universe, from our position in it, or someone else’s. The first is that we assume the early inflation pushed matter outward far beyond our light bubble, which is the age of the Universe (minus the “dark ages”) before light could fully propagate and travel without obstruction, ie. 10-12 billion light years. The second limit is the Hubble expansion, wherein at very great distances, the accelerating expansion of the Universe since the Big Bang and inflation exceeds the speed of light, meaning very very distant galaxies can never be seen by us (no matter how long we wait) because the space between us and them is expanding faster than c. The photons can never get here. The photons within the first bubble can potentially reach us, if we wait long enough.

    That’s at least how I understand it.

  • Keller

    I’m just a Jr. in high school and I’m doing this topic called ” what lies beyond the edge of our universe” ever since i was a little kid i have always had the question of what else is out there? they tell us that it is finite. but how do we actually know this for a fact? we have never been able to get out that far. we hear theories saying that there is a parallel universe. all this just blows my mind about this subject

  • Ralph

    I love the debate of God vs no God because it allows me to flip the non-believers argument on them.  That being … I don’t believe in something that I can’t see or feel or prove … and yet they must believe in dark matter.  

    They have to believe that, although 95% of all matter is invisible, it is there!  Talk about being alike!  They have a holy trinity!  Dark matter, dark energy and dark flow!  Wow!

    The theory of dark energy was created because they found out that the universe is not slowing down which had to happen in order for the “big bang” to occur.  It is, in fact, speeding up!  

    This is a law in science … not theory … when a body is set in motion, it immediately begins to slow down.  So what is going on?

    The facts about dark matter have been known for over 100 years.  The theory of dark matter was created in 1933 by astronomer, Fritz Zwicky, yet none of us were ever taught about it in school.  Outside of college, I doubt that it is being taught now.  You must ask the question … why?

    This may be the answer to that question.  In a great article concerning the big three … dark matter, flow and energy, Chris Miller wrote:

    “Today, scientists are searching for the mysterious dark matter not only to explain the gravitational motions of galaxies, but also to validate current theories about the origin and the fate of the universe.”

    Read the last few words.  We need to validate!  Why?  Why not admit you have a faith?!?

    If you look at science over the years, you have to laugh at almost all of theories that were handed down, yet a few were sacrosanct.  One of those being gravity.  Yet, for over 100 years, scientists have known that the theory of gravity is bunk.  We should all be floating off into space!  95 % of EVERYTHING can not be seen.  Therefore, dark matter … one of the holy trinity.  This re-validates gravity.

    You may read this and laugh, but NON-BELIEVERS have a faith also.  All the theories are just that … theories.  In order for the big bang to not fall by the wayside, like all of the theories of the past, we created the trinity.  What is next?  

    I have been studying this argument for over 35 years, and I have yet to find a single reason to be a non-believer.  In fact, it has strengthened my faith.  How is your faith holding up?

  • Athiest

    There is no god. Anyone who truly knows anything about any of this would know that, lol. Keep religion out of this.


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