200,000 Elliptical Galaxies Point the Same Way

KentuckyFC sends us to arXiv, as is his wont, for a paper (abstract; PDF preprint) making the claim that 200,000 elliptical galaxies are aligned in the same direction; the signal for this alignment stands out at 13 standard deviations. This axis is the same as the controversial alignment found in the cosmic microwave background by the WMAP spacecraft.

Why?

[bcmm (768152)]

Do they give any reason that this might be so? Are the galaxies in the same area? Did they all form from some insanely massive rotating structure or something?

Re:Why?

[dashslotter (1093743)]

Does it really matter? 200,000 elliptical galaxies can't be wrong!

Re:Why?

[by Anonymous Coward]

From the paper:

"A discussion of possible causes for these alignments is beyond the scope of this paper. "

i.e. We don't know....

Re:Why?

[yada21 (1042762)]

You translated it wrong. A more accurate rendation is "can we have some more funding please?"

From TFA

[Kozar_The_Malignant (738483)]

From the paper:

"A discussion of possible causes for these alignments is beyond the scope of this paper. "

The sentence abouve is followed by: "R. Buniy et al. (2006) discuss a universe that is not spherically symmetric due to magnetic fields or cosmic defects in the context of the CMB alignments. A large scale cosmic magnetic field acting on protogalaxies in the early stages of galaxy formation seems to provide a possible mechanism for explaining the elliptic and spiral spin alignments and has been proposed as a mechanism for causing the CMB alignments by Campanelli et al. 2006."

i.e. We don't know....

i.e. but here a couple of ideas.

Re:Why?

[bughunter (10093)]

Well, beyond the scope or not, they did discuss it briefly, pointing out other papers that may lend insight.

But one possible cause they did not address is selection bias. Have they shown that they did not introduce any selection bias in the sampling of galaxies? I would hope for at least a list of hypothetical sources of bias that they then shoot down.

Re:Why?

[TinyManCan (580322)]

Perhaps they did not have any clue as to the 'why' but thought that the data was interesting enough to warrant further research.

This is a great way to get working on the 'why', as without this paper no one would be looking at it.

This is one way that science is done. They probably postulated that the alignment of galaxies would be random, and when they tested this hypothesis they found that the data did not match. Publishing that result so that others can start working on it is the next step in this process.

Re:Why?

[smoot123 (1027084)]

The three most important words in science are not "I've got it!" but "Gee, that's odd."

Re:Why?

[Alsee (515537)]

I'll see your "Gee, that's odd" and raise you an "oops".

-

Forget "why?" I wanna know "What!!???"

[ukemike (956477)]

Everyone is asking "why?" as in "Why are they aligned." My first thought was, "What the hell are they all pointing at?" Is it God? Is it the Restaurant at the End of the Universe? Is it Mecca? Maybe it is just a REALLY big magnet. The answer to the 'what' question might go a long way toward answering the 'why' question.

Anyway since I don't think that galaxies are likely to change their orientation, and remain tidy spiral galaxies, this suggests that there was a common influence on the creation of all of these galaxies!

Re:Why?

[beckerist (985855)]

Why? Why admit that "they don't know why" when the data might be right there! You have to keep in mind, to discover these sort of patterns comes from completely indirect viewing. This was all done by observing redshift which means that only one in hundreds of characteristics were monitored. That's like saying "200,000 people are overweight" by knowing that they eat at a fast food joint 3 times a day. There will be some inaccuracies and one could only draw that conclusion by other, much closer observation. Moreso, the statement made was "200,000 galaxies are pointed in the same direction." -- not incorrect!

My point is that they could very well have the reason "why" in their data, but chances are it would require a much further in-depth study of the individual galaxies themselves (or at least the common threads between them.) To get this pushed out the door now it at least gives others (and probably more qualified individuals) a chance to then take this data and run. Patience, we'll probably get the "why" (or at least some solid theories) soon enough, young Padawan!

Re:Why?

[MontyApollo (849862)]

I don't know how it works with astrophysics and cosmology type stuff, but in other fields of physics, research is often divided between experimentalists and theorists. It might be the case where the author doesn't feel qualified to say why and thinks it would be better for theorists to jump in. Or he may think it is more important to establish is results and have them verified first before moving on.

Also, if he did try to explain it, then it could really slow down how long it takes to get published because of the peer review process. His explanation would probably be highly questioned, and it would take longer to reach agreement with the peer reviewers. That might be why he said it was beyond the scope of the paper. He wanted to get the less controversial material out there first, then he could concentrate on the more controversial material in a different paper.

Re:Why?

[mr_mischief (456295)]

That is one reason for something to be beyond the scope of paper. Another is that the paper has already hit the publisher's word limit. A third is that the topic at hand has been narrowly discussed for clarity or for time restraints on the project. A fourth is that the paper could become unwieldy if tangential topics are included.

It could be a combination of any or all of those. "Further research is needed to determine why this is so" is not so vague, and could be used if that was the exact meaning intended.

Re:Why?

[Ash Vince (602485)]

Explaining 'beyond the scope of this paper' _IS_ saying they do not know why.

Sort of yes.

Anyone who has done Physics (or any other cutting edge science) to a high enough level will know that this is always true. The maxim I remember was that every answer asks a thousand questions. This is certainly true in terms of the astrophysics of spiral galaxies.

Nobody even fully understands gravity even though the current understanding was presented by Newton and is known to break down as soon as you apply it to more than one body of approximately equal mass.

They could have waited until the paper they published didn't leave some nagging great question answered, but they would have been waiting an eternity to publish an infinitely long paper that nobody would have ever been able to finish reading anyway. Since this is impractical, they published what they knew and left it to their successors (or themselves in a few years) to answer why. Even if they had have answered this why they would have found more why's just around the corner the someone could have posted to slashdot anyway.

Re:Why?

[M1FCJ (586251)]

it's a long string and all of the galaxies are tied to it, like beads...

Re:Why?

[jimstapleton (999106)]

if 200,000 eliptical galaxies jumped off of a cliff... would you?

Re:Why?

[ATMD (986401)]

No, I imagine I'd be pulled off the cliff whether I liked it or not by the massive gravitational field...

Re:Why?

[notque (636838)]

Because they are terrorists. From the article,

"The axis of the CMB alignments has been referred to as the Axis of Evil"

Re:Why?

[iluvcapra (782887)]

It might mean that the angular momentum of the universe is nonzero, if a majority of them are turning the same direction. Or, even if they all cancel out, that momentum in the early universe tended to be oriented in a plane. (IANAP, just a guess but seems logical)

I'm curious if the Milky Way is a part of the alignment.

Re:Why?

[ATMD (986401)]

OK, I may be making a fool of myself here, but how can the entire Universe's angular momentum be non-zero? Surely momentum can only ever be relative to your frame of reference - and by definition, any frame of reference you can think of will be within the system you're trying to measure.

Although... thinking as I type here... say you were sitting on a massive spinning top, and all you could see was the spinning top. You'd still feel centrifugal force, as a result of its spinning. Could be an interesting explanation for dark energy?

(and yes, now I remember that important word "inertial" from A-level Physics lessons. Meh...)

Re:Why?

[B'Trey (111263)]

Your first thought was correct. You'd feel centrifugal force (actually centripetal force - centrifugal force [wikipedia.org] is actually a convenient fiction) only because of the mass outside the top which you're spinning in relation to. Unless there's a metauniverse outside the universe which influences this one in some fashion, and this universe is spinning relative to that one, then talking about the angular momentum of the universe seems as though it should be nonsensical.

Why would it

[Moraelin (679338)]

IANAAP either, but I see it like this: imagine you have 4 spinning tops in the corners of a square. (The spinning tops are the galaxies.) The square itself doesn't spin, but the round things in the corners do. If all 4 rotate in the same direction, the system has a decidedly non-zero angular momentum, namely the sum of the 4. You can also easily find a frame of reference (e.g., centered the centre of the square and with the X and Y axes aligned with the side of the square) that doesn't rotate, and measure everything relative to it.

Or if it makes it easier to imagine, think of the science gag of having a very fast spinning flywheel in a suitcase. Ask someone to carry it for you, or leave it around and see if anyone tries to steal it. (Though these days it'll more likely be the blown up by the SWAT or whatever equivalent your country has.) If the suitcase is horizontal (lying on the side), someone's going to have a beast of a time trying to pick it up. Or if it's standing, they'll have a beast of a time taking a corner with it. Though the suitcase (universe) doesn't rotate, the flywheel (galaxy) in it does, and the angular momentum of it all is very much non-zero.

Now think of a suitcase with 4 flywheels in it, or 200,000 little flywheels. The suitcase itself doesn't rotate, the centres of the wheels don't rotate around anything, but the total system has a total angular momentum. Anyone trying to mess with that piece of luggage is in for a bit of surprise.

Re:Why?

[Maury Markowitz (452832)]

> but how can the entire Universe's angular momentum be non-zero?

Excellent question. So excellent that it led to an entire alternate model of gravity. A trip to the wiki is always useful: Brans-Dicke theory

So, anyone want to put odds on dark matter going the way of the cublical atom in, say, ten years?

Maury

Re:Why?

[Kingrames (858416)]

IANAP = I am not a planet?

Pluto? is that you?

Why Not?

[NReitzel (77941)]

Einstein did not say that there cannot be a center of the universe.

What he did say is that for the purposes of measurement, there exists no privleged metric. All this says (All?!) is that there is no overall coordinate system that will be superior to all other coordinate systems.

If things started out as a big bang, on some scale, we will find a "center" of the universe. Is this an astronomy-shaking discovery? No. Maybe a tremor or two, for diehard relativeists. We already know that for specific purposes, there is often a preferred metric for computational or navigational purposes. Remember back in the Apollo program when the physics guys tried to explain that at a specific point, the coordinate system for the spacecraft shifted over from Terra-centric to Luna-centric, and the reporters looked at the "jog" in the plot and asked if the spacecraft would feel a "lurch" as it passed this point?

It's not nearly as big a deal as, say, whether Pluto is a "planet" or not. Pick a label, pin the sticker on the rock, except in this case, the rocks are superclusters of galaxies.

Re:Why Not?

[mlewan (747328)]

"If things started out as a big bang, on some scale, we will find a "center" of the universe. "

I thought that was not the case. The big bang started in a point, but a point that is equally far from every other point in the universe, so there is no "centre". It is not a very intuitive statement, but that is what I understood from some article or other on the subject.

IAAP (I Am A Physicist), and...

[JeanPaulBob (585149)]

...well, I have a MS in Physics, anyway. Well, Applied Physics. In semiconductors. Anyway...

I think another poster said it a bit more intuitively, that the point is now smeared out everywhere. That sounds roughly right to me.

Another thing to realize is that the Big Bang doesn't mean that an explosion happened in a single point in empty space, and then everything expanded outward. It's that space itself was compressed down into a single point, and then expanded. There was nothing outside the Big Bang for it to expand out into. Every point in the universe was infinitely closer together. All the energy was really close together--really dense--so it was really hot. Then as things got less dense, the temperature decreased. In one sense, everywhere is the center of the Big Bang.

This is also why distant galaxies can be receding away from us faster than the speed of light. Because expansion doesn't mean that galaxies are moving through space. (In relativity, nothing can move through space faster than c.) Instead, the distance between us is increasing as space itself expands. (You can visualize that as making two marks with a pen on a deflated balloon, and then blowing up the balloon. The two marks don't move on the balloon, but they do get further apart.)

Re:Why Not?

[shma (863063)]

Rather, the fact that the universe has no 'center' is a POSTULATE of big bang theory. The assumption is that the universe is isotropic and homogeneous, i.e. that the universe looks the same in any direction from any location. While this is obviously false on small scales (the center of the sun, for instance, does not look the same as a point on the surface of the earth), on scales large than the largest structures, on the order of hundreds of megaparsecs, you can begin to see evidence for it. The best evidence for isotropy comes from the cosmic microwave background radiation, which is the same in any direction up to one part in 10^5. These small inhomogeneities in the background imply small inhomogeneities in mass density at the time it was created, 600,000 years after the big bang. Those regions of increased mass eventually formed the galaxies we see today. Getting back to your original question, assuming isotropy and homogeneity, there can obviously be no center of the universe, because it would have to stand out from other points. Likewise, if there was a preferred axis of revolution for all galaxies, then the universe would not be isotropic. That's why this claim is a bit difficult to accept, given the massive success of big bang theory.

Re:Why Not?

[Maury Markowitz (452832)]

> If things started out as a big bang, on some scale,
> we will find a "center" of the universe.

But understanding why this is so is what makes all of this fun.

Remember that modern metric theories, of which General Relativity is just one, posit that the universe is four dimensional. Three space dimensions and one time dimension make up a four dimensional "spacetime". Unless you have seen an explaination of exactly what this means, it's just words, like "the universe is gizifa". This can lead to misunderstandings.

I'll try to explain what this means, using a model I'm sure you've seen before, but likely poorly explained. Consider a balloon, partially inflated. The surface of the balloon, the "skin", is effectively a two dimensional object. The balloon as a whole is three dimensional. You have a two dimensional surface enclosing a three dimensional volume. Still with me?

The reason we use this model is because it is very similar to our model of the universe. In this model everything you see around you, the three dimensional world, is the "surface" of a larger four dimensional construct. Just as the skin of a balloon is a 2D surface of a 3D space, everything you see around you is in the 3D skin of a 4D space. Still with me?

Consider the balloon again. Critically, there is no "center" to the surface. Where is the middle of the surface of a sphere? Where is the middle of the surface of the Earth? The question itself is just "wrong". In the case of the Earth we arbitrarily decided to draw lines on it in certain placed, latitude and longitude. You could do the same with a balloon, make the neck the "north pole" for instance. By the same token we could have chosen some other coordinate system entirely, let's put the "west pole" in Ecuador!

There is a point of the balloon as a whole that can be thought of as the center, through. Its in the space "below" the surface that's filled with air. The same is true of the Earth, the center is down below us, about 6400 km away. But, critically, that point does not lie on the surface.

Now one more thing to consider. Draw some dots on the outside of the balloon. Label one of them "milky way". Now start inflating the balloon. You'll notice that the dots will move away from each other as you inflate them. In fact, from the point of view of the "milky way", all the other dots are moving away from it. But the same is true of all the other dots too. No matter which one you pick to observe, you'll see that everything moves away from it. And that's because, for lack of a better way to put it, space itself is getting bigger. In fact, the dots aren't really moving at all relative to their original locations on the surface of the balloon, their real motion is along a line drawn into the middle of the volume, that "real center".

In the case of the universe the same thing applies. We look out in space and we see that everything is moving away from us. This is surprising if the universe is a 3D space, but complete expected if it's 4D. So where is the center of the universe? It's "down" somewhere. And what is that missing direction? Well we already said it, it's time. So what does that mean?

That means the center of the universe is a point in time, not space.

As soon as you really grasp this model you'll see why everyone likes it. For one, it trivially answers lots of different questions:

1) why is everything moving away from us?
  it's not, everything is just "inflating"
2) why do we appear to be in the middle?
  its just the way it looks, and it looks the same way everywhere else too
3) why are we moving apart at all?
  because time is going forward (just look at your watch)

Hope this helps!

Maury

Re:Why?

[fygment (444210)]

The author states that the reasons for the orientation are beyond the scope of the paper. But the implication of the orientations is that the universe is not spherical. I have had only one course in cosmogeny (origins of the universe) and all the models lead to symmetry. So any indication of a lack of symmetry implies that we are missing some big piece of the puzzle. Combine this with the tenousness of many of the theories of cosmology (eg. Big Bang ... far from perfect and getting further ) and the picture emerges that there is not a lot that is actually known about the structure of the universe. Despite all the bravado and pat statements in the media, all we have are half-baked guesses. Mind you, does it really matter? Given our very short lives in the grand scheme of things, the lack of knowledge probably isn't hurting us.

Re:Why?

[WormholeFiend (674934)]

Mind you, does it really matter? Given our very short lives in the grand scheme of things, the lack of knowledge probably isn't hurting us.

We have short individual lives, but the knowledge that we discover outlives us.

If one day our descendants find ways to travel beyond our solar system, this knowledge might prove useful to them.

Re:Why?

[spun (1352)]

Fortunately, in a billion years Andromeda will merge with the Milky Way so we'll be able to get genuine Andromedan cuisine right here in the newly formed Andromilkeday galaxy.

Assumption busting...

[massivefoot (922746)]

Huh. I don't really have a great deal of specialist knowledge on cosmology, but this seems to put a lower bound on the distance over which we can assume the universe is isotropic (i.e. the same in all directions). The abstracts puts an upper bound on the redshift of the galaxies involved in the survey, which is presumably roughly equivalent to limiting the distance they are from us, but surely the fact that this net angular momentum axis is closely aligned with an axis identified in WMAP data indicates that this is a far larger scale phenomenon?

Re:Assumption busting...

[pla (258480)]

this seems to put a lower bound on the distance over which we can assume the universe is isotropic

I have to wonder - Could this particular anisotropy account for the Voyager paradox? That would set a much lower bound...

Even if not, though, I really find this sort of anomaly fascinating. Almost everything cosmology has found since the dawn of modern science has pointed to a bleak, cold, basically empty univers that goes on identically forever in every direction. Even learning that the universe has some underlying structure would somehow seem a lot more comforting.

Easy. They point towards the monolith

[TechyImmigrant (175943)]

They do. There's a monkey there with a bone as well.

and here is why they are all alligned

[FudRucker (866063)]

http://www.youtube.com/watch?v=Da2byMoEG30 [youtube.com]

galaxyzoo.org

[Kartoffel (30238)]

It's been posted before, but if this sort of thing interests you, get over to Galaxy Zoo and help them classify galaxies.

Maybe Dylan was wrong

[mcmonkey (96054)]

It seems you do need 200,000 elliptical galaxies to know which way the wind blows.

this explains star trek!

[kisrael (134664)]

So this might help explain in Star Trek how all ships are always keeping the same orientation / sense of "up"...

obviously...

[Connie_Lingus (317691)]

all your axis are belong to us.

A grain of salt

[Stranger4U (153613)]

I read the article, and there seem to be a few problems he doesn't really address. First, he assumes that all elliptical galaxies have a point-of-view from which they appear circular. I don't think anyone has determined this to be the case, and he doesn't really have a way to get this from his data. Secondly, he doesn't give much real discussion to the error in the measurements, which is significant. No preffered axis of alignment would fall well within his measurement uncertainties. Finally, the 13-standard deviations is not from any real sort of error propagation, but from some random computer generated results. Could be interesting, but to be taken with a grain of salt.

Re:A grain of salt

[bperkins (12056)]

> First, he assumes that all elliptical galaxies have a point-of-view from which they appear circular.

All ellipses have a point of view where they project as a circle. Are you saying that his elliptical galaxies aren't elliptical? Even if they weren't, how would that create a selection bias?

> He doesn't give much real discussion to the error in the measurements, which is significant.

How would "error in the measurements" cause a selection to a particular orientation?

Random error wouldn't move the average, just make the distribution wider. In fact random error ought to make the distribution more isotropic.

Re:A grain of salt

[Bazman (4849)]

His "random computer generated results" test is what we statisticians call a 'Monte-Carlo' test. Its perfectly valid, given the assumptions he is working under.

Suppose you throw 10 possibly biased dice and score 50 in total (where the average score would be 30).

You then get 10 definitely fair dice and throw them 100 times, counting the total each time. If these trials only score 50 or more once, then the chances of your possibly biased dice being fair are 1 in 99. That's pretty much what he's done.

With dice its possible to compute the probability exactly without doing the trials, since the behaviour of uniform probabilities (ie even chance of scoring 1 to 6) are well known and easy to compute. But if you have a situation of elliptical galaxies and their apparent projection on a sphere viewed from the earth then I suspect the computations may be harder...

einstein was right

[circletimessquare (444983)]

god doesn't play dice

he plays with magnets

Before we get too excited

[by Anonymous Coward]

Let's note that:

1) This guy is a high-energy physicist, not an astronomer.

2) He has two published articles on extragalactic astronomy, both from the early 90s, which have picked up a grand total of 4 citations.

3) He has put up 3 papers on the arXiv in the last few months, all on this subject. None of them are stated to have been submitted for review, and indeed they are not in the style of any of the major relevant journals.

Yeah, yeah, ad hominem and all that. I'll read it more carefully later if I have time (but I'm a bit busy writing a paper of my own, like, for submission and peer review and all that). He does appear to enjoy abusing statistics, both here and in his earlier papers.

I just kinda think that Slashdot could report on all the many scientific discoveries that are actually likely to be true, rather than grand claims based on a couple of preprints by someone with little experience in the field.

Re:Centre of the universe

[FuzzyDaddy (584528)]

They all point outwards from the centre of the universe.

Me.

Actually, this has already been observed. [wikipedia.org]

Re:which beam

[stoolpigeon (454276)]

nope - the turtle.
 
"See the TURTLE of enormous girth,
On his shell he holds the earth.
If you want to run and play,
Come along the BEAM today."

Re:I don't see how this matters...

[at_18 (224304)]

Now if these 200,000 galaxies are all in a particular region of the universe, THAT would be explosive news, but, unless I completely misread the article, this isn't the case.

It is the case. They were specially selected to be close to us (redshift < 0.20). I suspect these 200,000 galaxies are a fairly significant fraction of all the galaxies near us.
Of course, they are close to us because more distant galaxies would be too difficult to investigate, but this doesn't change the fact that they are all in the same particular region of the universe.

Re:I don't see how this matters...

[BlueStraggler (765543)]

My reading of the abstract is that he looked at a sample size of 200,000, and found a 13-SD bias to one direction in that sample size.

Re:Translation?

[Vellmont (569020)]

can someone give me the 'play by play' brief on the significance of the orientation of the galaxies and why the chance is so slim that they align as they do?


I'm not a Cosmologist, but one would expect galaxy orientation to be pretty much random. As an example, think about if you threw a bunch of nails in the air. At any given time you'd expect the nails orientation to be pretty random (ignoring air effects, and any bias given by your throw). If they all aligned in a certain way though, you'd be surprised and start looking for a cause. (In this case say a strong magnetic field in the room).

If this is true, there must be something orienting the alignment of galaxies. That could be either some bias in the big-bang, some outside force we don't understand, or something else.