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Dark Flow
September 25, 2008 2:28 PM Subscribe

Mysterious New 'Dark Flow' Discovered in Space. "As if the mysteries of dark matter and dark energy weren't vexing enough, another baffling cosmic puzzle has been discovered. Patches of matter in the universe seem to be moving at very high speeds and in a uniform direction that can't be explained by any of the known gravitational forces in the observable universe. Astronomers are calling the phenomenon 'dark flow.' The stuff that's pulling this matter must be outside the observable universe, researchers conclude."

Here's the paper (subscription required): A Measurement of Large-Scale Peculiar Velocities of Clusters of Galaxies: Results and Cosmological Implications.

NASA has preprints you can download: results and implications and technical details (PDFs).

posted by homunculus (73 comments total) 19 users marked this as a favorite

In other space news: Two Planets Suffer Violent Collision
posted by homunculus at 2:30 PM on September 25, 2008 [1 favorite]

Astronomers are calling the phenomenon 'dark flow.'

Pook joke liftoff in 3... 2... 1... oh geez I gotta go
posted by GuyZero at 2:30 PM on September 25, 2008

Pook == poop. Nothing like a typo to ruin a [good|bad|awful|execrable] joke.
posted by GuyZero at 2:31 PM on September 25, 2008

Where's Lord Asriel?
posted by NoMich at 2:35 PM on September 25, 2008 [6 favorites]

And I believe my new favorite euphemism for menstruation has arrived.

"Look, I'm sorry I'm so touchy. It's the Dark Flow".
posted by padraigin at 2:37 PM on September 25, 2008 [7 favorites]

Heh the comments on the first link are pretty magical.

However, this whole "shebang" is a thick spherical shape of galaxy clusters that exist along filiments of dark matter that surround a concentrated mass at the center that is the most massive of black holes, massive enough to make the known extremely massive black holes seem like pipsquaks. (No I didn't read about this particular theory in that book. I made this up all on my own.)
posted by Potomac Avenue at 2:38 PM on September 25, 2008 [1 favorite]

So when does Milla Jovovich show up?
posted by The Whelk at 2:39 PM on September 25, 2008 [1 favorite]

What.
posted by Mach5 at 2:47 PM on September 25, 2008

You know who else had some Dark Flow?

The Notorious B.I.G.
posted by PeterMcDermott at 2:49 PM on September 25, 2008 [2 favorites]

Hobbes: "What would you call it?"
Calvin: "THE HORRENDOUS SPACE KABLOOIE!"
Hobbes: "Hmm, that is better."
Calvin: "Almost anything would be."
posted by spiderwire at 2:52 PM on September 25, 2008 [4 favorites]

Dark Matter, then Dark Energy, then Dark Flow . . .

Has everybody forgotten Occam's Razor? This is the fucking luminiferous aether all over again. Your gravitational model just doesn't scale - fucking deal with it.

*drains the bottle of Jack and then proceeds to opine ignorantly about the poll tax*
posted by Ryvar at 2:59 PM on September 25, 2008 [12 favorites]

OMG JUST SEND MCCAIN TO OUTER SPACE AND HE WILL FIX THIS TOO.

There, I have just McCaininated the thread.
posted by Mister_A at 3:00 PM on September 25, 2008

And I am deeply sorry for it. This is more proof that the universe is big, weird, cool, and unruly.
posted by Mister_A at 3:01 PM on September 25, 2008

Inflationary bubble tugging the whole universe towards the unknown... Bush didn't cover that last night, did he?
posted by woodway at 3:04 PM on September 25, 2008 [1 favorite]

it's DUST

... sorry, I immediately thought of His Dark Materials
posted by Lacking Subtlety at 3:05 PM on September 25, 2008 [1 favorite]

As fascinating as all this is, it still doesn't answer the question: how do we keep Haruhi Suzumiya entertained enough to not get bored and destroy the universe?
posted by Marisa Stole the Precious Thing at 3:07 PM on September 25, 2008 [3 favorites]

That said, here was another comment that I think makes an important point:

Still, we accept the phrase "dark energy" because it heretofore seemed to be closely related to dark matter, and it kinda sorta made sense to lump the concepts together.

But this, the "dark flow", is just taking things entirely too far. We can (now) clearly see the flow is occuring, though we do not know its cause. It, the flow, is hardly "dark." Only the cause is.

Could this be so? My understanding of dark matter was that it was called such because the thing itself was not observable; only its influence was. But if this flow is observable, how can we call it "dark"?
posted by Marisa Stole the Precious Thing at 3:12 PM on September 25, 2008

How could it be 'outside the observable universe'? Wouldn't it violate relativity if some attractive force could propagate faster than light (if it propagated slower than light, then the stuff 'outside the observable universe' would be inside it)?

It works because the universe is expanding (metric expansion) -- so things can be receding from us so quickly that something moving at the speed of light towards us is effectively moving away from us (the standard rubber analogy is an ant walking on a stretching rubber band). It is confusing, particularly as we're always talking about nothing being able to go faster than light, but really nothing is -- the distance between points is just increasing.
posted by j.edwards at 3:14 PM on September 25, 2008

Maybe it's in between the observable universe.
posted by StickyCarpet at 3:14 PM on September 25, 2008

Inflationary bubble

The scientists deduced that whatever is driving the movements of the clusters must lie beyond the known universe.

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.

"The structures responsible for this motion have been pushed so far away by inflation, I would guesstimate they may be hundreds of billions of light years away, that we cannot see even with the deepest telescopes because the light emitted there could not have reached us in the age of the universe," Kashlinsky said in a telephone interview. "Most likely to create such a coherent flow they would have to be some very strange structures, maybe some warped space time. But this is just pure speculation."

Goddamnit, space is cool.
posted by jimmythefish at 3:16 PM on September 25, 2008 [4 favorites]

Pyry, my understanding of that quote is that the source of the flow lies outside of the Hubble Volume, not that the flow itself is moving incredibly fast.
posted by LionIndex at 3:16 PM on September 25, 2008 [1 favorite]

Yep, I read the space.com article as positing, What about pre-Bang, the stuff outside our bubble of space/time? Which is a separate point (I think) from the one raised by j.edwards re: expansion, how big is our bubble at any given moment? Seriously cool, I agree. Then again, my degrees are in English Lit, so I'm not about to doodle mathematical formulae to clarify this.
posted by woodway at 3:21 PM on September 25, 2008

jimmythefish: Goddamnit, space is cool

To quote JBS Haldane -- "Not only is the universe queerer than we suppose, it's queerer than we CAN suppose."
posted by symbioid at 3:32 PM on September 25, 2008 [1 favorite]

The stuff that's pulling this matter must be outside the observable universe, researchers conclude.

Wait, what?
posted by Mental Wimp at 3:33 PM on September 25, 2008 [2 favorites]

It's Jet Li, escaping from the Hades Universe, and we're all in for an ass-kicking.
posted by bwg at 3:35 PM on September 25, 2008 [1 favorite]

Please go stand by the stairs

/required
posted by Durn Bronzefist at 3:35 PM on September 25, 2008

Oh, and my guess: 3rd stage Navigator.

Somebody get the K.H. on the line, stat.
posted by Durn Bronzefist at 3:37 PM on September 25, 2008

great. who pulled the drain plug?
posted by sexyrobot at 3:45 PM on September 25, 2008 [1 favorite]

GuyZero : Pook joke liftoff in 3... 2... 1...

Fishies Go Pook Pook.

Mister_A : This is more proof that the universe is big, weird, cool, and unruly.

I like the idea of an unruly universe. One that never listens to it's parents, and then went and got it's eyebrow pierced, just to make a statement that it will not conform, damn it.

I bet if we checked, we'd totally find out that it's got a couple of disorderly conduct arrests on it's record.
posted by quin at 3:45 PM on September 25, 2008

The stuff that's pulling this matter must be outside the observable universe, researchers conclude.

Wait, what?
posted by Mental Wimp at 3:33 PM on September 25 [+] [!]

Brownian motion type theory?
posted by Durn Bronzefist at 3:46 PM on September 25, 2008

It is just a hole in the dimensional cushion fort. Needs more afghan.
posted by YoBananaBoy at 3:48 PM on September 25, 2008 [7 favorites]

I’ll take Dark Flow over Large Marge.
She’s scary.

“outside the observable universe” - great, it’s Chthulu - we’re a tiny bubble of space time subject to titanic forces beyond our comprehension and sight.

Well hell, it’d be a pretty boring existence if we got things all nice and wrapped up in the first few thousand years.

“We found a very significant velocity, and furthermore, this velocity does not decrease with distance, as far as we can measure”

*blink blink blink*
Cool!
posted by Smedleyman at 3:59 PM on September 25, 2008

That's pretty freaky, (Bowie)
posted by flippant at 4:00 PM on September 25, 2008

Fark silver surfer photoshop in 3...2...1...
posted by Durn Bronzefist at 4:01 PM on September 25, 2008

So, when this inflationary bubble bursts who do we need to bail out? And how much will it cost?
posted by never used baby shoes at 4:05 PM on September 25, 2008

There, I have just McCaininated the thread.

Well then I'll just have to Obamanate it: Obama Sends a Shot Over the Bow for NASA
posted by homunculus at 4:30 PM on September 25, 2008

"Has everybody forgotten Occam's Razor? This is the fucking luminiferous aether all over again. Your gravitational model just doesn't scale - fucking deal with it."
We do test alternative gravity models as alternatives to both dark matter and dark energy. Unfortunately for your comment, Occam's Razor generally seems to be indicating unknown forms of matter and energy over unknown forms of gravity. Research is continuing into both possibilities, and how to better decide between them, but saying gravity is wrong is frankly a bit useless unless you can come up with a better form of gravity that does the job without something at least as hairy as the dark sector.
Something weird is happening, and saying it isn't dark matter and dark energy (which fit the data excellently with very few extra parameters) just because physics has barked up the wrong tree before, until it eventually comes up with a simpler and better model - that's just not a good argument. Not until you can come up with a simpler and better model.
I keep using this analogy because it's a good one: In 1930 you might have been arguing that positing a nearly undetectable particle of dark matter was clearly the fucking luminiferous aether all over again and that conservation of energy and momentum in beta decays were just wrong and we should fucking deal with it.
26 years later the neutrino was detected.
posted by edd at 4:36 PM on September 25, 2008 [6 favorites]

We don't have a fucking clue. We admit this fairly often, then we go and write research proposals to find out more.
Would you rather we admitted we don't have a clue and then didn't try to find out what 95% of the universe was? Or would you rather we just made stuff up and pretended we did have a clue?
posted by edd at 4:53 PM on September 25, 2008 [5 favorites]

Just me, or is anyone else disturbed that this is the footnote to the thread?

"It's as if Earth and Venus collided with each other," said Benjamin Zuckerman, UCLA professor of physics and astronomy and a co-author on the paper. "...Apparently, major catastrophic collisions can take place in a fully mature planetary system."

"If any life was present on either planet, the massive collision would have wiped out everything in a matter of minutes — the ultimate extinction event," said co-author Gregory Henry, an astronomer at Tennessee State University (TSU).

When's the (post-humous) Douglas Adams book hitting bookstores? And who's buying the next round?
posted by woodway at 4:54 PM on September 25, 2008

What's that? You found some more dark stuff...crap.

You seem to see this as ego-threatening. "What?! My theory is incomplete???"

In reality, I'm guessing a lot of scientists are jumping up and down with excitement right now. And the thing that separates them from the theologians down the way (well, one thing) is that the questions are at least as exciting as the answers.
posted by Durn Bronzefist at 5:02 PM on September 25, 2008 [2 favorites]

When do the astronomers just admit they haven't got a fucking clue? Dark matter, dark energy, dark flow. That's three question marks.
"We've got it all figured out, well except for this dark stuff, but except for that, oh yeah and this other dark stuff and the other dark stuff over there, but other than that we've got it all figured out. What's that? You found some more dark stuff...crap."

But what's interesting about dark flow, if I'm understanding what they're describing in the second link correctly, is that it isn't "dark" at all. It's been observed directly. Apparently, so has dark matter. Inflation would account for dark flow, and "WMAP data released in 2006 support the idea that our universe experienced inflation." Which I'm guessing would just mean that the universe is larger than we can observe for now.
posted by Marisa Stole the Precious Thing at 5:03 PM on September 25, 2008

post-humourous.
posted by jimmythefish at 5:04 PM on September 25, 2008

When do the astronomers just admit they haven't got a fucking clue?

I read a lot of articles where astronomers and astrophysicists enthusiastically admit as much. It's one of the things I love about the fields.

"We just found this really cool thing! We have no goddamned clue what it is! Isn't that awesome?"
posted by lekvar at 5:22 PM on September 25, 2008 [3 favorites]

Theologians and philosophers enjoy a good question too FWIW, where theologian ≠ Pentecostal VP candidate. Jimmythefish, clarification appreciated. In light of the theology vs. science comment upthread and the anti-Narnia "god is dead" message in Pullman's trilogy, writing sci-fi beyond the grave seems humorously relevant.
posted by woodway at 5:35 PM on September 25, 2008

Is this related?

"Astronomers have discovered a most bizarre celestial object that emitted 40 visible-light flashes before disappearing again."
posted by nickyskye at 5:50 PM on September 25, 2008 [2 favorites]

I knew inflation was getting bad here in the States, but now you're telling me inflation is *universal*? Is this going to require another bailout?
posted by jamstigator at 6:01 PM on September 25, 2008

When do the astronomers just admit they haven't got a fucking clue?

from Wikipedia:

Have You Got It, Yet?

"Have You Got It, Yet?" is an unreleased song written by Syd Barrett during the short time in which Pink Floyd was a five-piece. At the time, David Gilmour had been asked to join as a fifth member and second guitarist, while Barrett, whose mental illness and difficult nature were creating issues with the band, was intended to remain home and compose songs, much as Brian Wilson had done for The Beach Boys.

Barrett's unpredictable behaviour at the time and idiosyncratic sense of humour combined to create a song that, initially, seemed like an ordinary Barrett tune. However, as soon as the others attempted to join in and learn the song, Barrett changed the melodies and structure, making it impossible for the others to follow, while singing the chorus "Have you got it yet?" This would be his last attempt to write material for Pink Floyd before leaving the band.

I really like the idea that there are things out there, so utterly distant that the light from them has not had time to reach us during the 14 billion year lifespan of the universe. On this kind of scale, our universe may never be old enough for those things to be knowable by us, but I'd much sooner we start the funding to try and work it out than pay to have another war somewhere, anywhere.

Goddamnit, space is cool.

Jimmythefish, you said volumes.
posted by mandal at 6:03 PM on September 25, 2008

^ links borked, ~~I forgot to add the root~~ they have a dark root.
posted by mandal at 6:04 PM on September 25, 2008

GALACTUS HUNGERS
posted by Halloween Jack at 6:26 PM on September 25, 2008 [1 favorite]

1) Brane Theory. Our universe exists on a brane, or a sort of super-universe structure. The big bang happened on the "surface" of the brane, flinging space-time and matter far and wide. (This came about by two branes banging together.)

Here's the fun part*, there's nothing that says that our big bang could be the first and only, or even the only contemporaneous big-bang event on our brane, and these events could overlap. An object quite literally outside our little bubble of space-time could be sharing its gravitic love through an inter-universal interaction of some stripe.

2) String Theory. Gravity is too weak to be neatly explained, so String Theory posits that gravity comes to us from a journey through hidden and imperceptible dimensions, as many as twelve of them, neatly curled up inside the four we can directly perceive. Perhaps the curl becomes less neat in some parts of our universe, and gravity assumes more of its rightful power over matter in these places.

3) Fermi's Paradox. If there's life out there, why haven't they said hello? Because they're too busy building dyson spheres on a supra-galactic scope, manufacturing black holes far beyond their usual scale to harvest their energy.

Take yer pick.

(*actually, the really fun part are the bulks, an arrangement of infinite branes, and super-bulks, arrangements of infinite bulks... but this is the fun part for the Dark Flow discussion.)
posted by Slap*Happy at 6:45 PM on September 25, 2008

Has everybody forgotten Occam's Razor? This is the fucking luminiferous aether all over again. Your gravitational model just doesn't scale - fucking deal with it.

With all fairness aren't we approaching the problem of Dark Whatever better than the Standard Consensus regarding ether? Saying (thank you eddy) distinctly and fully "this is totally weird" or "This shouldn't happen and we have no idea why." rather than trying to come up with explanations like sudden land bridges and unseen forces?

This is really weird, and they are saying so, rather than pretending it's totally fine and makes sense according to theory X, with a few footnotes and puppets

PROGRESS!

i think.
posted by The Whelk at 6:51 PM on September 25, 2008

Double Post Be Damned!

There's some confusion about "outside the observable universe", thinking of the universe like the ocean with a horizon. We can see the first ship from our ship's crow's nest, but we can't see the third ship, whereas the ship in the middle can see everybody. It doesn't work that way... in space!

OK. If we can observe an object behaving a certain way, that means the light it gives off has reached us. All light through a vacuum travels at the same speed, because the speed of light is a universal, it's as fast as stuff can go. So! Gravity only travels as fast as the speed of light. So, if gravity reaches the object in space and makes it move, light from that object or the dark matter lensing effect the light of further objects passes through) reaches it at the same time. So, if we can see the object move, we can see the thing that made the object move at the same time, because it's all moving at the speed of light, baby!

So, when they say the monstrously massive thing causing these galaxies to move is outside the observable universe, they mean it's outside our four-dimensional bubble of space-time, otherwise we'd see it.
posted by Slap*Happy at 6:57 PM on September 25, 2008

Images of broken light which
dance before me like a million eyes
That call me on and on across the universe
Thoughts meander like a
restless wind inside a letter box
they tumble blindly as
they make their way across the universe
posted by flapjax at midnite at 7:36 PM on September 25, 2008

...but saying gravity is wrong is frankly a bit useless...

o, rly?
posted by sexyrobot at 8:11 PM on September 25, 2008

It's Jet Li, escaping from the Hades Universe, and we're all in for an ass-kicking.

Holy shit, I thought I was the only one who saw that movie.
posted by adamdschneider at 8:15 PM on September 25, 2008

outside the universe
posted by hortense at 9:59 PM on September 25, 2008

Holy shit, I thought I was the only one who saw that movie.

And even then, it won't prevent Jet Li from making you his bitch. And me as well.
posted by bwg at 10:51 PM on September 25, 2008

I'm not even smart enough to understand which part I don't understand.

I think, though, that I really like how there's already way more going on (that is, there's been way more information gathered) than anyone knows what to do with. That is intense.
posted by From Bklyn at 12:15 AM on September 26, 2008 [1 favorite]

Astronomy is the most humbling science. By virtue of being free from the need to be economically useful, astronomers can spend their time looking for stuff that they have no hope of ever understanding. That's excellent for the psyche of us all in a Lovecraftian way.

Biologist: I just learned what this protein does! Hubris++
Physicist: Awesome, I can explain the magnetic properties of this material! Hubris+=3
Mathematician: QED, mofo! Hubris+=5
Astronomer: The large-scale universe is screwing with us. Maybe intentionally. Were you to understand it, your brain might seize. Hubris -=50
posted by a robot made out of meat at 7:10 AM on September 26, 2008 [2 favorites]

sexyrobot: "...but saying gravity is wrong is frankly a bit useless...

o, rly?"

My point isn't that weird things aren't happening. The Pioneer anomaly is weird, cosmic acceleration is weird, and galaxy cluster members velocities and the velocity dispersions and rotation curves of galaxies are weird, and a whole range of other observations are all weird.

My point is that just saying something is wrong isn't very helpful. If I hand you the Einstein field equations it's perfectly reasonable to say that they don't seem to match up with what we observe in those cases. It's not so perfectly reasonable to say that the solution must be to modify one part of those equations and twiddle with gravity and not say that there's something else we're missing (whether it be a dark something or an unaccounted for but otherwise fairly mundane force acting on Pioneer). It's ok to try twiddling with gravity and come up with a better idea, but until you have that better idea you can't go ruling out the competitors.

If I hand you the Einstein field equations along with a couple more rules that do make it fit the observations, you can't say that I should dump those and still spend my time fiddling with the left hand side of the equation rather than the right and keep trying to change gravity instead, not without a really good reason I should focus on adjusting one part of the equations and not another. If you can come up with a good way to do that then excellent, we can go and compare the results and see if we can come up with an experiment to tell them apart.

Just saying "dark matter doesn't exist, your gravity is all wrong" seems to me rather like telling Sherlock Holmes that his rather convoluted solution to the murder seems way too contrived and that instead the murderer must have had a gun that can shoot round corners, and when he asks how such a gun would work he's told "I don't know, I'm not a gun expert". Saying a solution to a problem seems too improbable is not really enough. You need to come up with a better alternative - a real competing theory.
posted by edd at 7:28 AM on September 26, 2008 [4 favorites]

[Star Wars "Dark Side of the Force" joke]
posted by Uther Bentrazor at 8:04 AM on September 26, 2008

Saying a solution to a problem seems too improbable is not really enough. You need to come up with a better alternative - a real competing theory.

That's a fair point. Let me put it differently then: the only thing positive one can say about the luminiferous aether is that it was only *one* fudge-factor entity. Positing the existence of *three* fudge-factor entities to explain the difference between theory and our observations seems like a step backwards.

And no pointing at string theory and shouting "they started it!"
posted by Ryvar at 10:38 AM on September 26, 2008

"WMAP data released in 2006 support the idea that our universe experienced inflation."

So the financial meltdown has escaped the solar system now.
posted by Mental Wimp at 12:27 PM on September 26, 2008 [1 favorite]

Damn you, jamstigator!!!
posted by Mental Wimp at 12:33 PM on September 26, 2008

A friend of mine made the astute point that "dark flow" sounds like the name of a sheep disease.

Other than that I have nothing to add besides
Great Jumping Jehosaphat!
this is so damn cool.
posted by Kattullus at 9:59 PM on September 28, 2008

A True Image from False Kiva
posted by homunculus at 12:05 AM on October 1, 2008 [1 favorite]

Do We Live in a Giant Cosmic Bubble?
posted by homunculus at 11:05 PM on October 1, 2008

Space Dust
posted by homunculus at 2:03 PM on October 2, 2008

Five Pictures of Deep Space Like You've Never Seen Them Before
posted by homunculus at 5:17 PM on October 6, 2008

Astronomers find a planet denser than lead
posted by homunculus at 5:18 PM on October 6, 2008

The Statistical Universe: We look up to an expanse of sky that is billions of light-years in size, but the universe may be far larger than what we are able to see.
posted by homunculus at 2:39 PM on October 18, 2008

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