![]() | This article was nominated for deletion on 28 September 2008. The result of the discussion was speedy keep. |
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![]() | This article was nominated for merging with Great Attractor on October 2010. The result of the discussion was no consensus. |
Someone who truly understands this topic needs to do a major cleanup I believe. Unless I'm missing something, the particle horizon listed as being at a distance of 46 billion light years is pure claptrap. The universe is 14 to 16 billion years old. Therefore nothing can be further away than say 16 billion light-years. Did someone mistype a 4 instead of a 1? — Preceding unsigned comment added by 84.75.50.123 ( talk) 22:51, 29 October 2011 (UTC)
Because of the expansion of the universe, there are distance measures which give distances appearing larger than the distance light could have been travelled since the beginning. See here for example;
http://www.astro.ucla.edu/~wright/CosmoCalc.html
--
134.76.205.137 (
talk)
08:22, 22 March 2012 (UTC)
I'm wondering about the inability for telescopes to see anything later than 380,000 years after the big bang. That is a relatively small period of time in universal and earth terms, so does that mean that if humans had evolved 380,000 years sooner than they did, they would have been able to see the big bang with their telescopes (ie our current level of telescopy)??
This is not really a comment about notability or verifiability, but this stuff is silly. There are no physical effects from objects outside the observable universe, which is why it is called the observable universe. Although there are a few papers which keep claiming that a hypothetical external "eternally inflating" universe has some statistical or physical effects, if you can't see stuff electromagnetically, it can't suddenly gravitate on to you either. Likebox ( talk) 22:08, 23 September 2008 (UTC)
Ok--- after reading the link--- this effect can be rephrased to apply to a single observable patch. The statement they make is that there are observable velocity fields of galaxy clusters today, which they believe are relics of primordial gravitational interactions in the inflating universe. What this means is that they are postulating that there are fluctuations of local velocity in the inflating universe (which requires a modified view of what kind of stuff can fluctuate back then), and this statement can be phrased as "gravitation from objects that have moved out of causal contact", but only if you insist on being purposefully obscure. Likebox ( talk) 22:21, 23 September 2008 (UTC)
Well, thanks for clarifying. I wasn't quite sure if gravity can interact beyond this "observable universe" border (even if I was sure before), to be honest, I understood it that way. I'm only an amateur in astrophysics ;) But this way it makes a bit more sense, if I have understood it right this time ;) ColdCase ( talk) 23:12, 23 September 2008 (UTC)
I am not going to comment on the section above which uses terminology and frames of reference with which I am wholly unfamiliar. That said, my understanding of what I read is that this phenomenon evidences the existence of a physical universe of which our known, so-called "observable universe", is a part, which is on a scale at least one order of magnitude larger than the measurements of the observable universe. __ meco ( talk) 06:35, 26 September 2008 (UTC)
Couldn't it be that it's somthing that is behind the "haze" from the time when the universe was opaque, since light couldn't go thru but there was nothing stopping gravity from propagating? --
TiagoTiago (
talk)
14:07, 29 November 2011 (UTC)
It's a paper and a press release. It might be something or it might not. The way to find out is to wait. We don't go writing an article based on the press release and linking it on the breaking news page and rewriting observable universe as though everything had suddenly changed. Space.com is not a reliable source for information about cosmology, and press releases are never reliable no matter how respectable the institution they come from. Science does not work this way. I'm not going to nominate the article for deletion because I hate deleting things, but I do think it shouldn't have been written. -- BenRG ( talk) 23:40, 27 September 2008 (UTC)
A grad student told me that there's an off-the-cuff reason to mistrust this type of thing. A cosmological momentum fluctuation is a vector perturbation, and he explained that the FRW solution suppresses these with a time dependent factor that is large. The (classical, but I didn't think of it) example he gave me is a hot gas of photons, with a random fluctuating momentum. The temperature of the gas goes down, and this is a photon-by-photon effect. I don't know what happens for slow moving massive stuff in FRW. Likebox ( talk) 23:39, 16 December 2008 (UTC)
Perhaps someone should compare this "recent find" with the Wiki page on the Great_Attractor. The area of space where this dark flow was discovered is the same area of space first reported in 1973. The Great Attractor appears to have been "rediscovered"!
NOTE: Placing a link in the "See Also" section may not be enough to explain this gross error on the part of the so-called "discoverers" of "Dark Flow".
97.103.58.89 ( talk) 10:53, 25 January 2009 (UTC)Paine Ellsworth painius@aol.com
I compared both and found that they are both in the Centaurus region (although the Dark Flow article didn't mention distances), seeing as the "Great Attractor" is obscure enough for me not to of heard of it or seen it in most articles about Astronomy on WP (only found it one time in the Dark Energy section), it could be possible, but highly unlikely, that they have just never heard of it and neither had the press. But i don't think it is likely. GundamMerc ( talk) 03:18, 20 February 2009 (UTC)
Okay, the new sections recently added to this article (The universe as a gravitational drainage basin, The location of the Great Attractor in a small closed universe) are fairly quirky and likely OR, but the latest (Why the universe's gravitational field is geocentric) is just absurd:
The passage quoted from David Bohm clearly says nothing of the sort. Unless a reliable source is provided quickly to show that this is not just crackpot nonsense, I will remove it. Gandalf61 ( talk) 10:59, 3 October 2010 (UTC)
I agree. -- dab (𒁳) 20:23, 3 October 2010 (UTC)
I don't have time to add http://www.astro.auth.gr/~tsagas/Publications/Journals/PRD/PRD14.pdf in the text so I'm just going to put it in the references. Given the authorship and recent Nobel prize in physics, I think it's important enough for the introduction. Dualus ( talk) 04:09, 9 October 2011 (UTC)
Should we perhaps mention lack of support from Planck data be mentioned in the opening section? at the moment it seems to lean too much towards "this is a confirmed as real thing". Geni ( talk) 21:40, 3 June 2013 (UTC)
There's already a section on whether this article should have been written. As I understand it the criterion for keeping an article is not whether it's factually correct, but also WP:NOTABILITY. Is the theory of "Dark Flow" notable? AadaamS ( talk) 13:55, 29 August 2013 (UTC)
Is anyone disputing that Planck found no evidence for dark flow? The paper by Atrio-Barandela only seems to say that Planck data doesn't contradict WMAP data. Also we shouldn't be relying on a wp:primary arXiv source. If this paper is important it should have been written about somewhere. Bhny ( talk) 23:51, 5 July 2014 (UTC)
![]() | This article was nominated for deletion on 28 September 2008. The result of the discussion was speedy keep. |
![]() | This ![]() It is of interest to the following WikiProjects: | |||||||||||||||||||||||
|
![]() | This article was nominated for merging with Great Attractor on October 2010. The result of the discussion was no consensus. |
Someone who truly understands this topic needs to do a major cleanup I believe. Unless I'm missing something, the particle horizon listed as being at a distance of 46 billion light years is pure claptrap. The universe is 14 to 16 billion years old. Therefore nothing can be further away than say 16 billion light-years. Did someone mistype a 4 instead of a 1? — Preceding unsigned comment added by 84.75.50.123 ( talk) 22:51, 29 October 2011 (UTC)
Because of the expansion of the universe, there are distance measures which give distances appearing larger than the distance light could have been travelled since the beginning. See here for example;
http://www.astro.ucla.edu/~wright/CosmoCalc.html
--
134.76.205.137 (
talk)
08:22, 22 March 2012 (UTC)
I'm wondering about the inability for telescopes to see anything later than 380,000 years after the big bang. That is a relatively small period of time in universal and earth terms, so does that mean that if humans had evolved 380,000 years sooner than they did, they would have been able to see the big bang with their telescopes (ie our current level of telescopy)??
This is not really a comment about notability or verifiability, but this stuff is silly. There are no physical effects from objects outside the observable universe, which is why it is called the observable universe. Although there are a few papers which keep claiming that a hypothetical external "eternally inflating" universe has some statistical or physical effects, if you can't see stuff electromagnetically, it can't suddenly gravitate on to you either. Likebox ( talk) 22:08, 23 September 2008 (UTC)
Ok--- after reading the link--- this effect can be rephrased to apply to a single observable patch. The statement they make is that there are observable velocity fields of galaxy clusters today, which they believe are relics of primordial gravitational interactions in the inflating universe. What this means is that they are postulating that there are fluctuations of local velocity in the inflating universe (which requires a modified view of what kind of stuff can fluctuate back then), and this statement can be phrased as "gravitation from objects that have moved out of causal contact", but only if you insist on being purposefully obscure. Likebox ( talk) 22:21, 23 September 2008 (UTC)
Well, thanks for clarifying. I wasn't quite sure if gravity can interact beyond this "observable universe" border (even if I was sure before), to be honest, I understood it that way. I'm only an amateur in astrophysics ;) But this way it makes a bit more sense, if I have understood it right this time ;) ColdCase ( talk) 23:12, 23 September 2008 (UTC)
I am not going to comment on the section above which uses terminology and frames of reference with which I am wholly unfamiliar. That said, my understanding of what I read is that this phenomenon evidences the existence of a physical universe of which our known, so-called "observable universe", is a part, which is on a scale at least one order of magnitude larger than the measurements of the observable universe. __ meco ( talk) 06:35, 26 September 2008 (UTC)
Couldn't it be that it's somthing that is behind the "haze" from the time when the universe was opaque, since light couldn't go thru but there was nothing stopping gravity from propagating? --
TiagoTiago (
talk)
14:07, 29 November 2011 (UTC)
It's a paper and a press release. It might be something or it might not. The way to find out is to wait. We don't go writing an article based on the press release and linking it on the breaking news page and rewriting observable universe as though everything had suddenly changed. Space.com is not a reliable source for information about cosmology, and press releases are never reliable no matter how respectable the institution they come from. Science does not work this way. I'm not going to nominate the article for deletion because I hate deleting things, but I do think it shouldn't have been written. -- BenRG ( talk) 23:40, 27 September 2008 (UTC)
A grad student told me that there's an off-the-cuff reason to mistrust this type of thing. A cosmological momentum fluctuation is a vector perturbation, and he explained that the FRW solution suppresses these with a time dependent factor that is large. The (classical, but I didn't think of it) example he gave me is a hot gas of photons, with a random fluctuating momentum. The temperature of the gas goes down, and this is a photon-by-photon effect. I don't know what happens for slow moving massive stuff in FRW. Likebox ( talk) 23:39, 16 December 2008 (UTC)
Perhaps someone should compare this "recent find" with the Wiki page on the Great_Attractor. The area of space where this dark flow was discovered is the same area of space first reported in 1973. The Great Attractor appears to have been "rediscovered"!
NOTE: Placing a link in the "See Also" section may not be enough to explain this gross error on the part of the so-called "discoverers" of "Dark Flow".
97.103.58.89 ( talk) 10:53, 25 January 2009 (UTC)Paine Ellsworth painius@aol.com
I compared both and found that they are both in the Centaurus region (although the Dark Flow article didn't mention distances), seeing as the "Great Attractor" is obscure enough for me not to of heard of it or seen it in most articles about Astronomy on WP (only found it one time in the Dark Energy section), it could be possible, but highly unlikely, that they have just never heard of it and neither had the press. But i don't think it is likely. GundamMerc ( talk) 03:18, 20 February 2009 (UTC)
Okay, the new sections recently added to this article (The universe as a gravitational drainage basin, The location of the Great Attractor in a small closed universe) are fairly quirky and likely OR, but the latest (Why the universe's gravitational field is geocentric) is just absurd:
The passage quoted from David Bohm clearly says nothing of the sort. Unless a reliable source is provided quickly to show that this is not just crackpot nonsense, I will remove it. Gandalf61 ( talk) 10:59, 3 October 2010 (UTC)
I agree. -- dab (𒁳) 20:23, 3 October 2010 (UTC)
I don't have time to add http://www.astro.auth.gr/~tsagas/Publications/Journals/PRD/PRD14.pdf in the text so I'm just going to put it in the references. Given the authorship and recent Nobel prize in physics, I think it's important enough for the introduction. Dualus ( talk) 04:09, 9 October 2011 (UTC)
Should we perhaps mention lack of support from Planck data be mentioned in the opening section? at the moment it seems to lean too much towards "this is a confirmed as real thing". Geni ( talk) 21:40, 3 June 2013 (UTC)
There's already a section on whether this article should have been written. As I understand it the criterion for keeping an article is not whether it's factually correct, but also WP:NOTABILITY. Is the theory of "Dark Flow" notable? AadaamS ( talk) 13:55, 29 August 2013 (UTC)
Is anyone disputing that Planck found no evidence for dark flow? The paper by Atrio-Barandela only seems to say that Planck data doesn't contradict WMAP data. Also we shouldn't be relying on a wp:primary arXiv source. If this paper is important it should have been written about somewhere. Bhny ( talk) 23:51, 5 July 2014 (UTC)