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.
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.
initial angular momentum? (Score:3, Insightful)
Re:Why Not? (Score:3, Insightful)
Sigh, what a load of bollocks (Score:2, Insightful)
And there's no way to tell how closely they're aligned, maybe many are 20-30 degrees off.
Would you still call that aligned? Is it still significant if one in a thousand galaxies are within 30 degrees of each other in orientation? Who knows? Who cares?
Not even a drop in the bucket (Score:2, Insightful)
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 Not? (Score:4, Insightful)
Re:Why? (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:5, Insightful)
Re:Before we get too excited (Score:2, Insightful)
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:IAAP (I Am A Physicist), and... (Score:2, Insightful)
For 2-D people that live on an expanding 3-D ballon, everywhere is the middle.
We 3-D people live in an expanding 4-D universe, for us everywhere is the middle.
That means if you go forever in the same direction,
you will eventually end up where you started.
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: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:Why? (Score:5, Insightful)
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Re:Why? (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!
Re:Before we get too excited (Score:1, Insightful)
The trouble with saying that "anyone who wants to can look at the pictures..." is that there's far more to astronomical data analysis than just downloading the raw data and running your favorite tests on them. The ellipticities in this sample, for example, are calculated in the data pipeline from a very simple geometrical measurement. To actually use them to find an effect this small requires additional reduction. For an idea of what's involved with this particular data set, take a look at this paper [arxiv.org], which uses the same data towards a different end, but likewise requiring precise measurements of the ellipticity and position angles. As you can tell by a glance at section 2.2.2 (and references therein), there are a whole host of instrumental calibrations that have to be done and selection effects to be investigated, and which Dr. Longo ignores. (Someone upthread also mentioned some of these.)
So the issue is not that Dr. Longo dares to work outside his field. It's that he doesn't seem to know how to go about doing what he wants to, and doesn't want to get his work checked by the people who are experienced in doing this kind of stuff and dealing with the nastiness that is modern astronomical instrument calibration. There are actually quite a few high energy folks who have made the switch from high energy to astrophysics (one is on my committee), and they learn that you can't take a list of raw numbers from a astronomical data catalog, run some binning and simple curve fitting on them, and expect to get a meaningful result any more than you could easily discover the top quark from the raw events list of a particle detector. Also, as I say, there is some dubious use of statistics, but the main point is that he's starting from data that simply isn't yet usable for his task.
As far as your naked-eye hunches, I suspect that it's an unintentional selection bias (by you) or something. The idea of checking for galaxy alignments is not new--indeed, it's a fundamental test of cosmic isotropy--and an effect large enough to be noticed by the naked eye would've been measured by now. I don't doubt what you think you saw, but I do doubt that you could see a real effect that easily.