Posted on 08/30/2007 6:47:29 PM PDT by jbp1
I have studied a sample of 200,000 elliptical galaxies with redshifts <0.20 from the Sloan Digital Sky Survey (SDSS) to investigate whether they tend to have their ellipticities aligned along a particular axis. The data show a 13 standard deviation signal for such an alignment. The axis is close to the spiral spin axis found previously and to that of the quadrupole and octopole moments in the WMAP microwave sky survey
(Excerpt) Read more at science.slashdot.org ...
Maybe, but consider two things. First there's evidently some anistropy in the WMAP that seems to match up. Second, the fellow mentions another analysis he did with some tens of thousands of spriral galaxies in the same database. It's a lot fewer than the 200K elipticals because he needed to be able to resolve the direction of rotation. Again he found a preferred direction. So that's three independent lines of evidence. I'd say something's up.
A giant black obelisk....dimension ratio 1 x 3 x 9
Well, suppose there are some clusters of strongly elliptical galaxies. Then your best correlation would be to place these on the “equator” of your alignment, and you would not be measuring any tendency of the galaxies to align themselves at all. That is, you would be detecting an inhomogeneity of the spatial distribution, not an isotropy of axial alignment.
Also, look at Fig 3 on page 6 of the paper. Note the irregularity of the average ellipticities. On the “best fit” graph, note the outlier above the line at sin(gamma) = 0.2, and the outlier way below the line at 0.1. If the effect is real, how did these bands near the equator escape it? What accounts for THEIR rogue behavior? A very cogent question since their deviation from the average is much greater than that accounted for by the linear model.
Obviously, I’m skeptical, but I wouldn’t want to rashly rule anything out. Please note the slashdot headline, though: “200,000 Elliptical Galaxies Point the Same Way” . This represents outrageous ignorance, or else maybe just a playful sense of anarchy and nihilism. The same spirit permeates our news and our politics, as every finding or “study”, however thin in substance, is reported as an absolute.
ping
Oops. At face value, these would be near the pole, not the equator, but that brings up another issue I have, which I had refrained from mentioning.
Comparing the two graphs of figure 3, note that the big error bars are at opposite ends of the x-axis. I would expect them to be associated with the poles because they represent a much smaller sampling space. ( Note the sine function folds the poles together. ) So this looks like some kind of kerfuffle to me.
Now, aren't you sorry you didn't take calculus for what was it, three semesters?
They have a life. Their lives just includes something useful to know.
It’s time for another beer................
Where do quasars fit into your diagram, and what is that “most distant object known?”
Huh?
If the effect is real, how did these bands near the equator escape it? What accounts for THEIR rogue behavior?
Local gravitational effects randomizing the orientations perhaps.
The biggest problem is that we DON’T KNOW which direction we are actually traveling. And in fact it really doesn’t matter (so says Einstein). Things like direction only come into play when you compare two objects. And even then if you’re comparing 3 or more objects, you need to use the same object as the reference for every other one.
As some people have already obliquely brought up. What if the universe is like a gigantic hall of mirrors? We each have a universe inside us which has a universe inside it and etc. And of course in the other direction as well. So many possibilities, and we only have a short time here to investigate them.
The data does not provide any information about the orientations of the galactic axes per se. All that is given is a spherical distribution of observed ellipticities.
If the galaxies were physically identical, then the variation in observed ellipticity would be due solely to the galactic orientations. However, there is presumably a distribution in the physical ellipticity as well, and any sort of clustering of this variation will be interpreted by the methodology as clustering in orientation.
Named Abell 1835 IR1916, the galaxy has a redshift of 10 [3] and is located about 13,230 million light-years away. It is seen at a time when the Universe was merely 470 million years young, that is, barely 3 percent of its current age!"
Where do quasars fit into your diagram
The existence of quasars suggests we are dealing with phenomena that present-day physics is at a loss to explain. But - they do exist. Try and ask somebody who doesnt believe in God to explain their existence.
Cant be - unless you are my wife.
BTW, I realize I wasn't very forthcoming in answering your question.
On the "best fit" graph, note the outlier above the line at sin(gamma) = 0.2, and the outlier way below the line at 0.1. If the effect is real, how did these bands near the equator escape it? What accounts for THEIR rogue behavior?I said it could be local gravitational interactions. But how can that be since it's a whole sky survey? What I was trying to say is that the volume swept out by sin(γ) varies proportionally increasing in sin(γ). So the statistical power of small sin(γ) bins is less and it's possible for a true galaxy cluster of correlated ellipticity to have larger effects at small sin(γ). That's what I was trying to say.
I realized later that even absent such clusters, the lesser volume also implies a higher variance so simple random effects could also account for it. I think I might have simply dropped them from the analysis.
And say, what did you mean by "equator?" Small sin(γ) will be pointing nearly along the "direction" of the plot, not orthogonal to it.
-PJ
It depends on whether its galactic arm was tapping on its neighboring galaxy.
-PJ
Good one, but it's 1x4x9 -- the squares of the first three prime numbers.
-PJ
Such alignment does not imply a net rotation in the universe. The net rotation of the universe is apparently zero.
All it would take would be a cluster of high ellipticity galaxies somewhere in view. These would be placed on the equator ( sin(γ) = 1 ) and you still have one degree of freedom left.
The whole method is to find the great circle which maximizes the average ellipticity of galaxies in its vicinity, so any kind of lumpiness in the spherical distribution is likely enough to provide you with one having a 4% greater value than the average, it would seem to me.
So the statistical power of small sin(γ) bins is less ...
This is presumably accounted for in the analysis, as the error bars indicate. A correct analysis would give equal weight to each galaxy.
And say, what did you mean by "equator?"
I had this backwards, as a noted in a self-followup. I also noted that I find the error bars confusing. The second graph follows the pattern you would expect with smaller samples at the poles, and hence larger error bars at small values of sin(γ), but the first one seems to be backwards in this respect.
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