Talk:Einstein Cross

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gravitational lensing phenomenon[edit]

The article should be rewritten to discuss the concept called "Einstein cross" and then give the configuration of objects mentioned in the current version as an example of this concept.

An interesting point is that we must speak of configurations of objects (source, lensing mass, and observer) which are gravitational lens, rather than single objects which are gravititional lens.---CH (talk) 22:57, 22 August 2005 (UTC)

such an article would sit at Einstein cross without the capital C. 03:51, 19 April 2006 (UTC)

Removed "expand" request[edit]

I removed the "expand" request template because the details of the formation of the Einstein Cross are more appropriately included in the main article on gravitational lensing. HEL 02:00, 29 October 2006 (UTC)

Merging with Gravitational Lens[edit]

I'm proposing merger because I don't think that there's enough information here to deserve it's own page. It would be much more suitable to be under the gravitational lens and mentioned as thus. Imasleepviking 20:35, 27 January 2007 (UTC)

I disagree; this article is about a gravitational lens, not the concept of Einstein crosses in general. If we merge this article into Gravitational Lens, then we would need to merge the other articles about individual gravitational lenses into it too, which wouldn't be a good idea. Mike Peel 10:59, 28 January 2007 (UTC)

why four "copies" instead of a ring?[edit]

I can see why a ring like phenomena like in the article on gravitational lensing should appear. But why a cross? What is this mechanism for this "quadrupolizing"? Some expert should explain that in the article. —Preceding unsigned comment added by Agge1000 (talkcontribs) 17:29, 20 September 2007 (UTC)

Agree. I came to this article after seeing the image somewhere else looking for an explanation. I was amazed that the image wasn't either a ring or several deformed arc-like shapes. So it would be good if the article explained this. Why four copies, why those precise orientations, why the copies appear undeformed (circularly simmetrical)... -- (talk) 12:38, 18 April 2010 (UTC)
Agree again. After reading the article I immediately thought "well why isn't it a ring?" Then I tried to imagine what shape the lensing galaxy must have to exert such an irregular influence on the passing light paths. At that point I decided an expert is needed. So, can anyone improve the article by answering this question? (talk) 22:48, 1 April 2012 (UTC)
Agree again. Without a more rational explanation, the quad pattern appears to support Time Cube! AltiusBimm (talk) 10:33, 30 May 2012 (UTC)
agree again, came here for the same reason, still no explanation hm. (talk) 21:33, 15 September 2013 (UTC)
7 years later and still no explanation... maybe add some annotation regarding article like to get experts attention? (talk) 23:59, 27 February 2014 (UTC)
Take a look here - cannywizard (talk) 08:54, 15 September 2014 (UTC)

It is quadruply imaged...[edit]

Einstein's Cross consists of 5 images:

  • 4 gravitationally lensed images of the quasar
  • 1 galaxy core

Maybe this section could be expanded and written with more clarifying diction.

--Mr Accountable (talk) 13:28, 28 September 2008 (UTC)

Well then, what is the reason for this "quadropole image"? Any form of bending of light towards a central mass, no matter how large the bending, would create "Einstein rings", but what is the mechanism behind how things may get to be quadruopoly imaged? How has the scientists been able to decide that it is not four different quasars in the picture?Agge1000 (talk) 16:32, 28 May 2011 (UTC)
Science is based upon proof, among many other things. The article fails to mention any proof that Einstein's Cross is in fact "a gravitationally lensed quasar" (this article, in fact, flatly goes against one of the core pillars of Wikipedia, namely, verifiability, perhaps due to having Einstein's name?). Where would all these assertions go if in a future it was demonstrated that Einstein's Cross was, after all, a group of five different objects instead of a warped, multiplied image of just one object? --AVM (talk) 03:48, 19 April 2012 (UTC)
It all depends on mathematical calculations and spectroscopic analysis, and we certainly aren't going to confirm or disprove any hypothesis here on a Wikipedia article talk page (that would be WP:OR). AnonMoos (talk) 16:38, 30 May 2012 (UTC)
You're right; we won't solve it here; that's not the purpose of a talk page. But we can point out weaknesses in the article so that a knowledgeable person can update it with verifiable external information. Is there a reputable source that explains why this is a cross and not a ring? As you can see many commenters here are wondering the same thing. Has no scientist asked this question? Has no scientist answered it? Then perhaps the entire article is unfounded. (talk) 14:56, 17 June 2012 (UTC)
Dude, you really can't prove or disprove anything unless you have a grasp of the relevant mathematics, and no reputable scientist will seriously listen to you for more than 15 seconds if you don't. There could be a number of reasons for such "symmetry breaking"; it might be nice to have an explanation of it on the article, but whether or not such an explanation is included, hand-waving unmathematical speculations on Wikipedia talk pages do not invalidate publisehd scientific results... AnonMoos (talk) 21:45, 17 June 2012 (UTC)
"a number of explanations", name one? i assume the other commentators here (like me) have at least basic knowledge in general relativity (university course). so it's not totally stupid unfounded question to ask. i don't know what your point is! you don't know the answer, obviously. no wrong in that. but apart from that? (talk) 21:45, 15 September 2013 (UTC)
"no reputable scientist will seriously listen to you" -- I'm not asking a scientist to listen to me, I'm asking a knowledgeable person to update the article.
"There could be a number of reasons" -- great, let's hear some.
"it might be nice to have an explanation of it on the article" -- yep, that's what I'm asking for. (talk) 13:16, 17 August 2012 (UTC)

anyway i've been searching google and there's a pretty detailed answer which i haven't worked through but the basic reasoning is that the mass distribution that functions as the lense has no spherical symmetry but propably is elliptic. maybe someone wants to check it and put some sentences into the article with this reference. (talk) 21:45, 15 September 2013 (UTC)

"forming a nearly perfect cross"?[edit]

Why is it called "nearly perfect"? In the image, it looks quite crooked. It seems that the description should be more along the lines of "roughly forming a cross shape". (talk) 17:42, 23 September 2010 (UTC)

This needs to be renamed to the quaser[edit]

There is consensus not to rename or move this article. Kraxler (talk) 16:08, 17 April 2015 (UTC)
The following discussion is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

Einstein Cross is a prediction with multiple examples. Latest is here [1]. Comments? --DHeyward (talk) 03:55, 8 March 2015 (UTC)

To be clear, "QSO 2237+0305" is the quasar commonly known as "The Einstein Cross". It is not the only Einstein cross, however. The link above is another example recently in the news of an Einstein cross and is known as Supernova Refsdal. The hatnote by Alsee to gravitational lensing is adequate due to Common Name. I also fixed the reference in SN Refsdal. The motivation behind the RFC was that the press is calling the supernova an "Einstein's cross" and the supernova article was referring readers here, not "gravitational lensing." A search for "einstein cross" brings a reader to the quasar, not the phenomenon so people reading the newspaper don't get the difference. --DHeyward (talk) 07:11, 24 March 2015 (UTC)
  • Oppose. The Einstein Cross is a particular instance of a general phenomenon known as gravitational lensing. The article about the phenomenon is called "Gravitational lens", and the article about the instance is called "Einstein Cross". I see no reason to rename anything. Maproom (talk) 09:06, 14 March 2015 (UTC)
  • Oppose per Maproom's rationale. To be honest, from the current wording of the RfC header, I'm not even able to parse what the OP is suggesting is the cause for a name change (nor what support the article supplied has upon that debate) but at present I don't see any kind of policy argument for renaming this article, which needs no disambiguation. Snow I take all complaints in the form of epic rap battles 09:22, 15 March 2015 (UTC)
  • Oppose An "Einstein Cross" is a term for a general phenomena with multiple examples, however it is also the common name given to one particular astronomical object (Quasar Q2237+030). I just edited the Hatnote to make things more clear. It now reads: This article is about a specific multiple imaged quasar named "The Einstein Cross" . For the general concept of Einstein Crosses, see gravitational lens. Alsee (talk) 22:21, 18 March 2015 (UTC)
  • Oppose per above comments. No renaming appropriate in the first place. I made a minor change to tidy the hatnote, but it already was substantially appropriate. JonRichfield (talk) 03:58, 22 March 2015 (UTC)
  • Oppose I was summoned by the bot. After reading the article and the entire talk page, I do not understand what the OP is suggesting as a name change or the rationale for doing so. "renamed to the quaser": What quasar? The quasar in the middle of the Einstein Cross? Isn't that its common name already, Einstein Cross, as it is a quadruple image? I oppose a name change per Alsee's comment above.--FeralOink (talk) 01:35, 24 March 2015 (UTC)
  • Comment (summoned by the bot) This is a particular instance of a phenomenon described elsewhere. Given that this particular quasar is often called the "Einstein Cross" (but this name is not rigorously exclusive), would it be reasonable to make the title more specific, e.g. "Einstein Cross (QSO 2237+0305)"? -- Scray (talk) 04:02, 30 March 2015 (UTC)

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.