200,000 Elliptical Galaxies Point the Same Way 448
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? (Score:5, Interesting)
Re:Why? (Score:5, Funny)
Re:Why? (Score:5, Informative)
"A discussion of possible causes for these alignments is beyond the scope of this paper. "
i.e. We don't know....
Re:Why? (Score:5, Funny)
From TFA (Score:5, Informative)
"A discussion of possible causes for these alignments is beyond the scope of this paper. "
Re:Why? (Score:4, Insightful)
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: (Score:3, Interesting)
Re:Why? (Score:5, Insightful)
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? (Score:5, Insightful)
Re:Why? (Score:5, Insightful)
-
Re: (Score:3, Insightful)
Forget "why?" I wanna know "What!!???" (Score:4, Insightful)
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!
Comment removed (Score:5, Insightful)
Re:Why? (Score:5, Insightful)
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: (Score:3, Funny)
Re:Why? (Score:5, Insightful)
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? (Score:5, Informative)
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? (Score:4, Funny)
Re:Why? (Score:5, Funny)
Re:Why? (Score:5, Funny)
Re:Why? (Score:5, Funny)
"The axis of the CMB alignments has been referred to as the Axis of Evil"
Re:Why? (Score:5, Interesting)
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: (Score:2)
Re:Why? (Score:5, Interesting)
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? (Score:4, Informative)
Couldn't resist: (Score:3, Funny)
Why would it (Score:5, Informative)
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.
I didn't mean just mass (Score:3, Informative)
Well, anyway, the thing with the tops and the briefcase was probably just an unneeded tangent. (I do a lot of those.) The important part is that the total system has a non-zero total angular momentum even if the centres of the tops don't move.
Of course, the galaxies themselves could still move around each
Heh (Score:3, Interesting)
Re:Why? (Score:4, Informative)
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: (Score:3, Insightful)
What's the relationship between the angular momentum of the Universe and the rotational velocity anomalies of outlying material in galaxies or intra-cluster excess mass? How would that account for the dark matter gravitational lensing results from last year? I'm not seeing why one has such an effect on the other.
Re:Why? (Score:4, Interesting)
You're right. That sucks.
Basically the idea behind BD, and the other ST and STV theories, is that there is an additional field, not just the tensor field of GR. One of the side-effects of the field in the BD theory is that angular momentum "falls out" of the universe. This is actually kinda important.
In traditional models, the conservation laws you know don't really _have_ to exist. For instance, if the universe was shaped like an egg, billiard balls would always roll into one corner of the table because there's more mass on that side of the universe. The fact that it is conserved says a lot about the universe, specifically that is symmetric around any point in 3-space. Conservation of angular momentum is similar; it says the universe is symmetric around other axis as well -- linear momentum would still be conserved in a universe shaped like a cigar, along any axis the gravity is still even, but in this case a spinning object would speed up and slow down. Conservation of energy is due to the fact that the universe is symmetrical in time, physics in the past is the same as it is today.
Ok, but like I said, those laws don't _have_ to be true, and this bugged the hell out of a lot of people over the years. I forget which one of them, I think Brans, was thinking about what would happen if you spun a dish full of water in an empty universe... would the water rise up the sides? And if it doesn't, why not? Isn't either answer a little weird?
The extra field in DB theory answers the question -- the answer is "yes", the water will rise up on the sides. It wasn't designed to do that, at least I don't think so, but it ends up popping out of the math.
So basically if you end up with odd angular momentum terms in the universe, it MAY suggest that some other model of gravity might be more correct. Right now everything we've ever measured can't tell between the various models, but this might.
Maury
Re: (Score:3, Informative)
Re:Why? (Score:5, Funny)
Pluto? is that you?
Re: (Score:3, Interesting)
Yes, it is, more or less: (from the FA)
Elliptic Galaxy Axis 183±8 deg 41±8 deg
North Galactic Pole 192.9 deg 27.1 deg
1st no. is right ascension (longitude for stars), second is declination (latitude).
This is really an amazing result. The galaxies way over there on the "left" side of the Universe know what the galaxies on the "right" are doing! It's so amazing, it makes you wonder if it might be wrong. For example, it might real
Why Not? (Score:5, Interesting)
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? (Score:5, Informative)
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.
Re: (Score:3, Insightful)
IAAP (I Am A Physicist), and... (Score:5, Informative)
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? (Score:4, Insightful)
Re:Why Not? (Score:5, Informative)
> 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? (Score:5, Interesting)
Re:Why? (Score:5, Insightful)
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: (Score:3, Interesting)
Layne
Re: (Score:2)
Re: (Score:2)
Layne
Re: (Score:3, Informative)
That's 400 million to 1 billion light years.
Right around the corner.
z=0.20 is sufficiently distant that the restaurants don't even deliver.
Re:Why? (Score:5, Funny)
Centre of the universe (Score:2)
Me.
Re:Centre of the universe (Score:5, Informative)
Re:Centre of the universe (Score:4, Interesting)
The fingers of god effect is simple - the doppler shift of a galaxy is proportional to the distance, according to Hubble's observations. If you do a plot of galactic positions, using the observed position in the sky and the red shift as the third dimension, you see what appear to be long, skinny clusters, all pointed directly at you. This happens because in tight clusters, galaxies are attracted to each other gravitational and have a range of velocities which is relatively large. So there's an added velocity on top of that caused by the expansion of the universe, which changes the distance you'd compute by Hubble's law.
Re: (Score:2)
They're pointing the way to God, but... (Score:2, Funny)
Re: (Score:2)
Holy Crap (Score:2, Funny)
They are running their spacecraft off of a Windows-MySQL-Apache-PHP stack? well I'll be
Re: (Score:2)
Assumption busting... (Score:4, Interesting)
Re: (Score:2)
Re: (Score:3, Informative)
Re: (Score:2)
Re:Assumption busting... (Score:5, Interesting)
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.
Re: (Score:2)
I think he means the Pioneer Anomaly (Score:2)
This is from memory, though, so it may have been resolved by now.
Re: (Score:2)
Layne
Re: (Score:2)
which beam (Score:2, Interesting)
Re:which beam (Score:5, Funny)
"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: (Score:2)
"See the TURTLE of enormous girth,
On his shell he holds the earth.
His thought is slow but always kind,
he holds us all within his mind."
Easy. They point towards the monolith (Score:5, Funny)
Re: (Score:3, Funny)
and here is why they are all alligned (Score:5, Funny)
galaxyzoo.org (Score:5, Informative)
Re: (Score:2)
Maybe Dylan was wrong (Score:5, Funny)
this explains star trek! (Score:4, Funny)
Um, no they don't (Score:2, Informative)
obviously... (Score:5, Funny)
Translation? (Score:2)
Re:Translation? (Score:5, Interesting)
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.
A grain of salt (Score:4, Interesting)
Re: (Score:2, Informative)
Re:A grain of salt (Score:5, Informative)
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: (Score:3, Funny)
Re: (Score:2)
True, but the assumption is that that direction corresponds to the axis of rotation. I tend to think that failure of that to be true would tend to add noise rather than a spurious result. Unless of course there was some other systemic effect, but that would be even stranger.
Interestingly his method does not distinguish up from down so it does not mean there is an excess of rotation in one direction. Also it would be real interesting to
Re: (Score:3, Informative)
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?
Actually there's a fair bit of evidence that elliptical galaxies are in fact 'tri-axial' - they have different sizes in all three dimensions, like a rugby ball or an american football that's been squashed slightly. Th
Re: (Score:2)
Re: (Score:2)
This would necessarily hold true purely by geometry (at least using the standard meaning of "elliptical galaxy"), even if his more rigorous condition (Earth happens to occupy that magic spot) has no cosmological basis.
Although we can hypothesize the existance of some bizarre shape that always looks longer than its width from any angle, that seems a bit of a stretch (no topology-geek pun intended) when ju
Re:A grain of salt (Score:5, Informative)
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...
I don't see how this matters... (Score:2)
Re:I don't see how this matters... (Score:5, Informative)
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... (Score:4, Informative)
Re: (Score:2)
You misread the article. If memory serves, by putting an upper limit on red shift the discussion is limited to galaxies in a particular region--namely closer to us. Galaxies further away would demonstrate higher red shift.
einstein was right (Score:5, Funny)
he plays with magnets
initial angular momentum? (Score:3, Insightful)
It's soooooooo fucking obvious... (Score:3, Funny)
Before we get too excited (Score:5, Informative)
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.
Little discussion of instrumental systematics (Score:3, Interesting)
I have little direct experience with this, but I suspect that optical distortions could be the cause of the effect he is seeing. The universe may very well have some weird features, but this paper is not a careful analysis.
It's the first lure of the rosetta (Score:3, Interesting)
Re: (Score:2)
Re: (Score:2)