Spooky "Dark Flow" Tracked Deeper Into the Cosmos; No Word on What's Tugging at Galaxies

By Andrew Moseman | March 12, 2010 5:18 pm

ComaClusterA year and a half ago, the team led by Alexander Kashlinsky of NASA proposed the controversial and ominously named “dark flow,” a massive gravitational force that is tugging at galaxy clusters, and that Kashlinsky says could be coming from beyond the limits of our own visible universe. Now the team is back with a follow-up study in The Astrophysical Journal Letters, and Kashlinsky says the team has tracked the dark flow out twice as far as before.

A quick note on dark flow: The reason Kashlinsky noticed it is thanks to the cosmic microwave background, a signature left over from 380,000 years after the Big Bang that permeates the universe. “The hot X-ray-emitting gas within a galaxy cluster scatters photons from the cosmic microwave background (CMB),” the NASA press release says. “Because galaxy clusters don’t precisely follow the expansion of space, the wavelengths of scattered photons change in a way that reflects each cluster’s individual motion.” Using data from the Wilkinson Microwave Anisotropy Probe (WMAP), which mapped the microwave background, the team managed to find this tiny effect when they looked at huge clusters of galaxies, and found something totally unexpected.

What the 2008 find showed was that these galaxies were moving in a way that the distribution of matter in our visible universe couldn’t explain, traveling a million miles per hour in a particular direction. Says Kashlinsky: “This is not something we set out to find, but we cannot make it go away” [US News & World Report]. The new study confirms this weird effect, and finds that it extends farther out, to at least 2.5 billion light years away. Where Kashlinsky’s first study relied upon three years of WMAP data and 700 galactic clusters, the new study grows those numbers to five years of data and double the number galactic clusters. The clusters appear to be zooming along on one particular line aimed at Hydra, Kashlinsky said, but “right now our data cannot state as strongly as we’d like whether the clusters are coming or going,” to or from Earth [USA Today].

While the universe itself keeps on expanding and expanding in all of the directions it can whiz, no one direction should be preferred, which is why the dark flow is so damned interesting. According to our best understanding of how the matter in the Universe was distributed, there’s no way of accounting for this flow. The obvious alternate explanation is a little unnerving: something outside of our visible universe is pulling on the matter that we can see [Ars Technica].

For another explanation of dark flow, check out Phil Plait’s at Bad Astronomy, written after the initial 2008 study.

Related Content:
80beats: Mysterious “Dark Flow” Is Tugging Galaxies Beyond the Universe’s Horizon
Bad Astronomy: Trans-Cosmic Flow Broadens Our Horizon

Image: NASA, the Coma Galaxy Cluster

CATEGORIZED UNDER: Physics & Math, Space
MORE ABOUT: dark flow, physics
  • Torres


  • Fay Lovecraft

    amazing. simply amazing! i got chills down my spine….happy chills…we’re not alone out here, there’s something else with us too…i hope…

  • drow

    Gives me the chills.There is so much we don’t understand.

  • Hawkeye

    It’s truly amazing… Here is more evidence that our current models of the universe are severely flawed, yet we keep building onto this house of cards with even more unicorns and other mythical creatures. Enough is enough. The emperor has no clothes! The big bang model requires so much magic to make it even halfway plausible anymore. It’s no longer science, but dogma.

    Anyone with true scientific objectivity can see we need a paradigm shift. Clearly something besides expansion is needed to explain the apparent red shift we see. My money is riding on the plasma cosmologists to win (with a side bet on John Dobson’s steady state model). I’m sure there are non-spooky explanations for these galactic cluster observations with either of these models.

  • Cory

    Lol, declaring a well-evidenced theory “a house of cards” because we occasionally have to adjust our model of it to suit new evidence is a fundamental misunderstanding of science imo. Particularly, suggesting that we should replace this theory with unverified extrapolations is just dangerous.

  • Albert Bakker

    #5 – Of PC disciples there are few left after CMB mapping and they are quiet for the most part, at least in my experience. Not so their angry offspring, the Electric Universe community. They number more, are more wrong and much more annoying.

    They believe the Concordance (Big Bang) model is just one big gravitational conspiracy against electricity. They aren’t so much concerned with producing (observational) evidence for their theories as with making converts by producing glossy books and flashy sites full of wrong (and admittedly some nice graphics) in which they elaborate on their heroic martyrdom for “true science” and why respected cosmologists are evil.

  • scribbler

    I proffer that new discoveries have proven that there is much we haven’t accounted for in the formation of the Universe. I suggest no particular model since as I said, there is no accounting for some of this information with our current model.

    So, unless and until something better comes along and new discoveries are made that enlighten us, we should at least acknowledge our ignorance.

    It is human nature to hold on to the familiar. True science to me, anyway, is sometimes saying, “I just don’t know…” I’m not trying to discourage speculation, in fact, just the opposite.

  • http://philosophiareflextions.blogspot.com Ernie M. Brewer

    Could it be proff of M-Theory? If this unknown phenomena is pressing or merging with our own universe, it proves that there are higher dimensions, right…?

  • Annie

    #8 – You would need to first prove there is, in fact, a pressing or a merging and that there isn’t perhaps another effect occurring to cause these results in the study.

    One thing is certain, scribbler is correct. We just don’t know… yet.

  • YouRang

    How is this unidirectional flow different from a local velocity? That is to say the Milky Way is not at rest with respect to the CMB. Instead in the past, it was reported that we were moving toward Virgo (the center of our local supercluster). It would seem that this effect ought to be aimed in the opposite direction away from Virgo (since we are seeing them as moving toward Hydra/Virgo), but this report might require us to reinterpret our local motion.

  • Mauritz

    What is so mysterious and spooky about a gravitational pull from something outside our view? If the universe is infinite in certain respects why not in size too? Why should the part we see be representative for everything else that could exist? The Big Bang and Evolution theories are in the same place, being constantly revised and improved even though the main idea stays the same. This shows it is time for that again,….exciting!

  • papercranes10000

    Evolution and the Big Bang are not in the same place. Evolution is a fact and is in a controlled environment that we understand. The Universe is far beyond our vision and our understanding. We are unable to conceive of just how small and insignificant we are in relation to the universe. Given the type of organism that we are, with all of our limitations, we will never understand the universe around us. Still, it is always nice to learn more.

  • Jay Fox

    So stuff is moving through the universe. We knew that. But how can anyone say with any certainty that moving matter is either being pulled (by gravity) or being pushed (by the expansion of space/time). There is currently, to my knowledge, no way of proving either.

    There is so much that we don’t know. Questions:

    Does this article postulate that expansion/pulling is occurring at different rates in different places in the universe? What could explain that?

    How do we explain the expansion of the universe? Could it be the very wierdness of quantum mechanics itself? As I understand it, in the vacuum of space, particles pop into existence and then just disappear. What if when they pop in, they push space apart to make room. When they then disappear, they leave behind empty space. These particles are pretty damn small, but apparently there are a lot of them. What would the additive effect be if they were all accounted for in this manner? Their additive weight? Could this not be part of the “missing matter” conundrum? Or can it explain the dark energy question?

    I am not a physicist, nor do I play one on TV. Didn’t even stay at a motel last night. But I am curious about these ideas and would appreciate someone’s expert opinion on this.

  • Albert Bakker

    For people who are not that familiar with the (various types of converging) evidence for the standard Big Bang model and why so many apparently normal and even intelligent people “believe” in such a weird thing, Mark Whittle’s site I find a very good, clear and accessible introduction: http://www.astro.virginia.edu/~dmw8f/BBA_web/bba_home.html

  • scribbler

    To J. F.: I just don’t know…


    See, this is where science begins. What would be evidence that what you say is true or false (I’m not asking, just saying that would be the next step; getting answers to all our questions) and how would you go about finding those elements of proof?

  • barry

    “…a massive gravitational force that is tugging at galaxy clusters, and that Kashlinsky says could be coming from beyond the limits of our own visible universe. …”
    It would be well worth mentioning whether this “tug” is emanating from the Sloan Great Wall of galaxies or not . http://space.mit.edu/home/tegmark/sdss_scinews031101.pdf
    See p. 2 of this doc .

  • barry

    any thoughts on this will be greatly appreciated

  • Albert Bakker

    13, 15# – But it would be good I think, to also think of obvious objections to your idea and if you can’t answer them at least mention them. I’d think of one. Virtual particles are the same as normal particles (well a matter/anti-matter pair existing for an extremely short time-interval associated with the mass or energy they “borrow” from the vacuum, but otherwise are indistinguishable from normal particles) and as far as I am aware normal particles don’t push space aside to exist in space like a duck pushes water aside to float on water. If anything mass bends space towards it, but even then it doesn’t do so by absorbing quanta’s of space (the underlying assumption seems to be space quantization by using the image of a hole in space left behind by an instantly disappearing virtual particle) or destroying it. There is still the same unaltered “amount” of space, or rather spacetime. But maybe there are subtle reasons to think of the whole thing in another way, I don’t know. Maybe you would have to enter the area of space/ time quantization and perhaps imagine some consequences from an extension of the uncertainty principle to these quanta in conjunction with time-energy uncertainty or something.

  • Albert Bakker

    16# – The Sloan survey extends to about 1 Bly as you can read at your own link, so no.

  • James E.

    I have a few question because there are a few things I am having understanding in this post.

    #1) “The reason Kashlinsky noticed it is thanks to the cosmic microwave background, a signature left over from 380,000 years after the Big Bang that permeates the universe.” – I assume that the radiation happened 380,000 years after the Big Bang and has persisted until today, not that he is saying the universe is 380,000 years old.

    #2) “The new study confirms this weird effect, and finds that it extends farther out, to at least 2.5 billion light years away.”…”The obvious alternate explanation is a little unnerving: something outside of our visible universe is pulling on the matter that we can see.” – From what I have read the furthest visible galaxy is 13 billion light-years away. Is he implying that the visible universe, the horizon if you will, is 2.5 billion light years away or that there is something exerting a force that we can’t see inside of the horizon, like dark matter?

  • Bill Boo Baggins

    I’m sure that the universe is expanding because someone tipped the petri dish a little for their science experiment.

  • Mauritz

    @12- No way! I promise you, both theories(big bang and evolution) will look much different than they do now 50 years from now. We do not understand it yet. Not even close.

  • m702

    It’s most likely a gigantic space ship that consumes galaxies and uses the matter to power itself. A galaxy itself doesn’t have much matter, but when you can eat 100-150k of them at a time you can sustain long flight times.. LOL…

    Awesome article.

  • William

    I wrote a paper predicting Dark Flow about 10 years ago. I submitted the paper to the American Physical Society for publication in 2004-2005. The paper was rejected as it conflicted with certain preconceived notions of String Theory. As a result, I copyrighted it in 2006, and gave up trying to convince non-believers.

    The paper is available from me, or you can find it at the USA National Copyright Office.

    The paper is Called “Gravitational Buoyancy As A Stronger Quantum Force.”
    Copyright #TXU1-317-859

    Read it completely and you will understand mathematically why things are what they are and why Dark Flow is predicted. There are even equations for determining dark flow values.

  • http://None Sheffield

    Isn’t the Universe always expanding at the speed of light? What happens at the boundary when light hits what was not part of our universe until the photons hit what was not part of our universe. Where is light going at the edges?

  • Hal

    Is our galaxy being pushed or pulled or a variation in a combination of both? In which direction, the future? Are we going or coming? Maybe we’ll never be able to see far enough into the future, or the past, to complete our knowledge. Maybe we won’t know until we arrive and even then we won’t know because we’ll never, ever be around to experience the complete the trip? Maybe we’re always doomed to partial answers. It’s a long trip you know. Now, that’s not acceptable, is it? lol

  • milton.s

    I have a theory. (one of millions) I see the universe existing in an endless sea of Energy which is constantly pulling and tugging on itself. It eventualy acretes into a tiny ball of enery, which we call the singularity, until the pull of external enery snaps it back to it’s original location. This snap we call the Big Bang. The change of enery into matter we call the Universe. This is happening countless times in the sea of energy.


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