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.

Comments

Why?

[bcmm]

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?

[iluvcapra]

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?

[fygment]

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?

[ATMD]

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:Assumption busting...

[pla]

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.

A grain of salt

[Stranger4U]

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.

Why Not?

[NReitzel]

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:Translation?

[Vellmont]

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.