Talk:Sloan Great Wall

???? When is a structure not a structure????

As it stands, the article opens by saying the sloan great wall is the largest known structure in the universe. At the end, it says that it is not a structure.

An astro prof. at my department gave a talk about this issue; the point being that it's hard to define what is and isn't a structure based on only visual information. If you just generate random points on a grid, a human looking at it will see structure; but since it was randomly generated, that structure isn't meaningful. There are (apparantly mathetmatically proven) techniques which allow one to determine whether or not an observed structure is meaningful or not, and I suppose the point is that the wall doesn't pass these sorts of tests. The article as is certainly just confuses, though.  :) --Starwed 23:36, 23 May 2007 (UTC)

Count me confused as well. I don't think I've ever seen an article so blatantly contradict itself. I mean, either it is a structure or it isn't - assuming that we have a consistent idea of what a structure is. And if it's not a structure, then how is it a thing at all? Should it be nominated for deletion? --Lazar Taxon (talk) 04:55, 27 November 2007 (UTC)

I probably wouldn't nominate it for deletion. As a piece of cosmology, it certainly is notable. The article just needs clean up, but AfD is never used for clean-up. Lawrence Cohen 00:06, 13 December 2007 (UTC)

Jmacwiki (talk) 02:20, 24 February 2008 (UTC)The argument that it's not a structure because it's not gravitationally bound strikes me as weak, no matter what -- that is, even without the current self-contradiction in this article. A possible contrary definition: It's a "structure" simply because its components share some salient history (for example, all being part of a single, unusually high-density blob at an earlier time). The point isn't to argue that "gravitationally bound" is not a meaningful condition, it's simply to point out that the word "structure" does NOT have such a meaning for most Wikipedia readers, probably including a majority of the readers of this page. Using the narrow cosmologists' definition doesn't do our readers any favors.

It's possible that the SGW is nothing but a chance collection of points (galaxies?) with absolutely no unifying condition. But assuming that it passes that minimal test, then I think it's fair game to call it a "structure". If we need to, to avoid confusing the cosmologists, we can point out that it's not gravitationally interacting. Note that the linked DTFE page also calls it a "structure", so that might need editing as well.

If it doesn't pass that minimal statistical test, then the article ought to start off with something like "The SGW is a chance alignment of galaxies(?) that appears as though they are part of a single ...." Having looked at the picture, I suspect it's more than chance, even though the SGW is so large that it may indeed not be a single (gravitationally bound!) object, and may never evolve into one.

So:

1. Is there ANY confirmation that the data pass that minimal test, OR that they don't? If not, then this is just an article about an article (the Gott & Juric report).

2. If anyone objects to "structure", please state what word would you suggest instead.

Less informative references

Three further references was found in the CfA Great Wall article, which do not seem to contain too much information to justify their reference: AIP Bulletin of Physics News, allesoversterrenkunde.nl, another one appears to be broken: [1] — Ylai 08:18, 27 August 2006 (UTC)

WikiProject class rating

This article was automatically assessed because at least one WikiProject had rated the article as stub, and the rating on other projects was brought up to Stub class. BetacommandBot 10:03, 10 November 2007 (UTC)

Quote by Jane Tang

Did she really say what the quotation states? It seems not to make sense. 82.20.28.142 (talk) 22:07, 9 February 2008 (UTC)

Maybe a little better: On NASA's picture page of the SGW (http://apod.nasa.gov/apod/ap071107.html), there is a bit more wording about this at the bottom. Jmacwiki (talk) 02:25, 24 February 2008 (UTC)

TomtheHand deletion of Quote by Tang

TomtheHand has deleted the entire section about "it's not really a structure", with the Edit Summary stating that she is not a reliable source.

The issue is not whether Tang is a reliable source, it's whether the content of her quote is accurate and relevant. She is, in fact, quoting more reliable sources, such as NASA's chosen author for the APOD caption: http://apod.nasa.gov/apod/ap071107.html. Jmacwiki (talk) 03:23, 9 April 2008 (UTC)

Eponym

Afaik, this is named after Alfred P. Sloan unless anyone knows any differently? Pomona17 (talk) 12:58, 15 December 2008 (UTC)

Yes and no. It was discovered by the Sloan Digital Sky Survey project, whose website (http://www.sdss.org/) says it has been funded by the Alfred P. Sloan Foundation (as well as by "the Participating Institutions, the National Science Foundation, the U.S. Department of Energy, the National Aeronautics and Space Administration, the Japanese Monbukagakusho, the Max Planck Society, and the Higher Education Funding Council for England").

So the SGW was named for its project (SDSS), which was named for its primary benefactor (APSF), which was named for Alfred himself. It's probably simplest to think of the SGW as being named for the Foundation, not the man. Jmacwiki (talk) 06:08, 12 January 2009 (UTC)

size of the observable universe

I have a question regarding the "1/60" of the observable universe. As I understand it the universe is 13 billion years of age, which means that we can observe nothing further than 13 billion light years away. Doesn't that mean that the observable universe has a diamater of 26 billion lightyears. In that case a structure of 1.38 billion light years should be about 1/20 of the size of the observable universe. ThorAvaTahr (talk) 13:14, 13 March 2013 (UTC)

Except the "expansion" of the universe stretches it out to about 96 billion light years across. Not that I believe the universe is actually expanding, mind you. - MazeHatter

Jan 2013?

This article states that the Huge-LQG was discovered in January 2013, but the article for Huge-LQG states that its discovery was in November 2012. MXVN (talk) 18:05, 8 August 2013 (UTC)