Wikipedia:Articles for deletion/Dark fluid


 * The following discussion is an archived debate of the proposed deletion of the article below. Please do not modify it. Subsequent comments should be made on the appropriate discussion page (such as the article's talk page or in a deletion review).  No further edits should be made to this page.

The result was   keep. —Tom Morris (talk) 14:55, 18 December 2012 (UTC)

Dark fluid

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This article appears to be a diverse collection of interesting but singular ideas trying to unify dark matter and dark energy into a single concept either through Chaplygin Gas formalism, dark matter/dark energy alternatives, or a complex scalar field. The sources which use the term all appear to lack appropriate peer review. The one peer reviewed article cited has a main thrust that explains generalized covariant phenomenology with respect to gravitation rather than a true "dark fluid" proposal. Another peer-reviewed article in the See Also section just talks about certain corrections to scalar fields in the context of quantum gravity. Another article was apparently published in Open Astronomy Journal which is only a step above Vixra in editorial rigor.

As such, this idea does not represent a standard theory or hypothesis which can stand alone as a singular article. The various proposals that use the term "dark fluid" can be covered, subject to their notoriety, on pages devoted to the individually notable dark matter/dark energy alternatives or, perhaps even better, in articles about notable theoreticians who might famously make such proposals (as my research shows, however, it looks like there may be only one researcher who got press coverage for this, though, according to his own webpage, he appears to have moved on to other more promising lines of inquiry).

Essentially, I'm asking the community to delete this page as being either a non-notable side proposal or, at worst, an example of an attempt to advertise for obscure theories and bringing them to a greater prominence than they might otherwise enjoy by including them in Wikipedia before there has been a proper peer review. Junjunone (talk) 16:33, 3 December 2012 (UTC)
 * A quick search of "Dark Fluid" and "Dark Fluid Theory" turns up very little, only a few forum threads with very few posts and an article or two, but nothing from the past couple of years or so. I'm not a physicist, nor am I even a student of physics, but this appears to be at best, a significantly obscure theory which is not being worked on by many or any current physicists, and has not been worked on since the bulk of this article was written in 2008.  I could be incorrect, so while I believe this article should be Deleted, it is only with low-moderate (20 - 40%) confidence that I do so.  Regards, Jeremy -- =) khfan93 (t) (c) 20:01, 3 December 2012 (UTC)


 * Keep The dark fluid topic itself seems notable. Searching for "Dark Fluid" on Google Scholar yields many hits. Just on the first page are 6 articles all published in mainstream peer-reviewed journals, all by different authors:
 * 1. "Cosmological model with viscosity media (dark fluid) described by an effective equation of state", J Ren, XH Meng - Physics Letters B, 2006 - Elsevier http://www.sciencedirect.com/science/article/pii/S0370269305017259


 * 2. "Dark fluid: A complex scalar field to unify dark energy and dark matter", A Arbey - Physical Review D, 2006 - APS http://prd.aps.org/abstract/PRD/v74/i4/e043516


 * 3. "Vacuum dark fluid", I Dymnikova, E Galaktionov - Physics Letters B, 2007 - Elsevier http://www.sciencedirect.com/science/article/pii/S0370269306015929


 * 4. "A FRW dark fluid with a non-linear inhomogeneous equation of state", I Brevik, E Elizalde, O Gorbunova… - The European Physical Journal C, 2007 - Springer https://doi.org/10.1140%2Fepjc%2Fs10052-007-0357-9


 * 5. "Non-adiabatic dark fluid cosmology", WS Hipólito-Ricaldi, HES Velten… - Journal of Cosmology and Astroparticle Physics, 2009 http://iopscience.iop.org/1475-7516/2009/06/016


 * 6. "Constraining the dark fluid", M Kunz, AR Liddle, D Parkinson, C Gao - Physical Review D, 2009, http://prd.aps.org/abstract/PRD/v80/i8/e083533


 * The nominator pointed out the Science daily article which counts as a secondary source. If a topic is notable but the article is deficient, the article problems are surmountable and it should be improved, not deleted. AfD is not for cleanup, as explained in WP:NOTFORCLEANUP. The main problems I see with the article are that it doesn't seem neutral in viewpoint of all the different ways of modeling dark fluid, and it has insufficient references, leaving it somewhat essay-like. Mark viking (talk) 22:12, 3 December 2012 (UTC)


 * Your searches are telling because they all refer to varying concepts surrounding a "dark fluid". The last one, in particular, is an interesting take because it merely treats the dark sector as a "fluid" in the sense of searching for a vocabulary term that allows for unification of the two components that they would like to parametrize. This is a different sense of dark fluid from the other suggestions including your source 2), 3), and 5). Source 1) uses a viscous term to break a degeneracy similar to one described in 6), but their preference for a "fluid" is related to a proposed set of equations which diverge from those recommended in 6).


 * This is a somewhat interesting cul-de-sac in the discussions of theoretical cosmology, but there isn't a simple definition for what a "dark fluid" is other than a mean combination of dark energy and dark matter. To write an article about this topic will require any author (including the current state of the article) to synthesize a discussion into something like an original manuscript. That's the only way forward for treating this subject as I see, so it looks to me like the "clean-up" you are proposing is against Wikipedia's rules.


 * The secondary source deals with only one treatment by someone who has used the term "dark fluid". If we were to base the article on that secondary source, it would necessarily exclude most of the other sources you cited.


 * Junjunone (talk) 14:06, 4 December 2012 (UTC)


 * Thanks for your thoughtful comments. I agree that there are a variety of approaches to modeling dark fluid. It seems the field of cosmology often has multiple theories proposed to explain experimental facts. For instance, within the topic of dark matter, there is cold, hot, warm, or mixed dark matter. There are baryonic sources of dark matter, such as MACHOs in the form of brown dwarfs, jupiters, and intermediate size black holes, and various distributions of molecular hydrogen clouds hitherto unobserved. The non-baryonic sources include many kinds of proposed particles, such as kinds of WIMP, axions, and tau or muon neutrinos. Non-Newtonian gravity theories could be considered a kind of non-baryonic source, or maybe a third category.


 * But none of the many, wildly different approaches to dark matter preclude the writing of article(s) about them. It is a matter of trying to summarize the different approaches, with references for verification and further reading. The dark matter article does a good job of this in my opinion and a similar type of summary could be created here for dark fluids. Mark viking (talk) 17:22, 4 December 2012 (UTC)
 * Yes, dark matter stands in contrast to this subject very well. Dark matter as a concept is very well defined from a particular theoretical response to a set of observational conundrums: it is the unobserved matter that is causing excess gravitational and dynamical effects. This is why we can have discussion of proposals such as "alternatives to dark matter" and define precisely what constitutes a "dark matter proposal" and what does not. The concept is well-defined in the secondary literature and throughout the field. Rather than a half dozen poorly-cited papers of marginal significance, there is an entire library of literature on which to write a set of articles.
 * Contrast this with dark fluid. There isn't even an agreed upon definition aside from the suggestion that there could be a connection between components of the dark sector (incidentally, dark sector is a term that is much more commonly used in the field, but I notice we don't have an article on the topic, perhaps because it is simply defined as the combination of dark matter and dark energy components of the energy budget of the universe). I just don't see how we can write an article based on a handful of speculative works that have no community development or robust investigation. Theoreticians come up with ideas every day that go nowhere. I don't think that a collection of proposals that happen to use the arbitrary term "dark fluid" deserve to be cobbled together to form the basis of an article on Wikipedia when no such other "review" exists in the wild. Junjunone (talk) 18:35, 4 December 2012 (UTC)


 * Keep An idea with sufficient discussion in academic literature to be notable. Even if people do not agree what constitutes dark fluid, it is still possible for an article to set out the main theories without original research. --Colapeninsula (talk) 14:29, 4 December 2012 (UTC)
 * What are the main theories? Junjunone (talk) 14:50, 4 December 2012 (UTC)


 * Keep The reason given for deletion "As such, this idea does not represent a standard theory or hypothesis" is not a good one. There are plenty of article son topics that have not reached the maturity needed to be standard theories or have even turned out to be incorrect and are now of historical interest. Derek farn (talk) 14:18, 6 December 2012 (UTC)


 * Keep. Although fringe topics are generally not encouraged on Wikipedia, the fact that no one currently knows what dark matter or dark energy are makes this theory a plausible explanation to what is currently observed in the universe. I see no reason to delete. The simple fact that this is not a standard theory is no reason to delete; it's not like this article requires a rejection of established physics such as quantum mechanics. StringTheory11 (t • c) 02:07, 7 December 2012 (UTC)


 * Delete There is no consensus on what the term "Dark Fluid" even represents, as has been observed above.  The current article certainly does NOT represent any broad scientific viewpoint.  Yes, the term is being used, but since there's not much agreement on what it means, an article that purports to claim that one definition is the correct one is skirting original research, neutral point of view, fringe science, and a number of other no-nos.  For now, I would say delete the article until there's some broader agreement on what the term means.  — Preceding unsigned comment added by PianoDan (talk • contribs) 16:18, 7 December 2012 (UTC)
 * Being published in several peer reviewed academic journals is major recognition of the concept. Mkdw talk 08:05, 11 December 2012 (UTC)
 * Ah, but WHAT concept? Can you find even a plurality of those (not terribly many) articles that use the term to mean the same thing?PianoDan (talk) 14:42, 11 December 2012 (UTC)
 * Note: This debate has been included in the list of Science-related deletion discussions. • Gene93k (talk) 02:47, 8 December 2012 (UTC)


 * Delete. Only a few sources, mostly ArXiv. Several hundred references are usually required to make a topic notable (or noted). Xxanthippe (talk) 03:00, 8 December 2012 (UTC).
 * According to which policy? WP:GNG requires only two or more (independent) references for notability.-- Cycl o pia talk  23:41, 16 December 2012 (UTC)
 * WP:GNG isn't a policy, it's only a guideline. To that end, there is an excellent guideline for Scientific Notability: Identifying reliable sources (natural sciences). It looks liks this shows that the sources aren't good enough for science. Junjunone (talk) 01:46, 17 December 2012 (UTC)
 * The link you mentioned is a pretty good guideline, if a bit naive in parts. The author seems ignorant that there is some peer review done for ArXiv (there are virtually no crank papers there, for instance), but they are correct in that ArXiv papers should not be considered as fully peer reviewed papers. But some of the sources quoted above are published in high caliber, mainstream physics journals: Physical Review, Physics Letters and The European Physical Journal. IOP publishes Journal of Cosmology and Astroparticle Physics and seems legit, but I don't have personal experience with it. Mark viking (talk) 04:34, 17 December 2012 (UTC)


 * comment Where are the secondary (non-primary) sources? IRWolfie- (talk) 01:58, 9 December 2012 (UTC)
 * Secondary sources I found with a quick Google search:


 * "Dark Fluid: Dark Matter And Dark Energy May Be Two Faces Of Same Coin", Science Daily, as noted above
 * "New Cosmic Theory Unites Dark Forces", Space.com,
 * "Dark Matter and Dark Energy… the Same Thing?", universetoday.com,
 * "Has 'dark fluid' saved Earth from oblivion?", New Scientist, 06 March 2008,


 * The Science Daily and New Scientist sources I consider reliable. Space.com and universetoday.com seem journalistic, but I cannot comment on reliability. Mark viking (talk) 23:17, 9 December 2012 (UTC)
 * All these reports are about Hongsheng Zhao's PhysRevD paper. Junjunone (talk) 21:52, 10 December 2012 (UTC)
 * Previously you were complaining that all of the sources were about different things, but now you are complaining that these sources are about the same thing. Please at least try to be consistent in your arguments. Phil Bridger (talk) 20:55, 12 December 2012 (UTC)
 * The secondary sources are all about one idea from Hongsheng Zhao. The primary sources are all over the map. It's really simple: there was a slow news day at the Science Journalist Bull Pen and Science Daily decided to write an article on a PhysRevD article by Zhao. This got picked up by space.com, UniverseToday and New Scientist. That's the sum total of the secondary sources for this topic. If you want to look at primary sources, I listed them above and they're all about different things. Clear? Junjunone (talk) 22:53, 14 December 2012 (UTC)


 * Relisted to generate a more thorough discussion so a clearer consensus may be reached.


 * Please add new comments below this notice. Thanks,  MBisanz  talk 00:26, 11 December 2012 (UTC)




 * Keep for now Appears encyclopedic and wp:notable, but hard to tell because of the (so far) lack of secondary sources in the article. North8000 (talk) 01:54, 11 December 2012 (UTC)
 * Keep - A Google search in regards to peer reviewed knowledge might not be a suitable test in this case. As long as notable scientific sources report back, in this case multiple academic journals, then a Google search of popular links might not be an accurate indication of its importance to science and in this case an encyclopaedia. Mkdw talk 08:00, 11 December 2012 (UTC)
 * Keep Notable per sources above, meets WP:GNG, disambiguating between competing concepts under the same name could be in order, if this is an issue, but this is dealt with editing, not deletion, per deletion policy. -- Cycl o pia talk  23:40, 16 December 2012 (UTC)
 * Keep: With rewriting for correct tone. הסרפד (Hasirpad) [formerly Ratz...bo] 05:25, 18 December 2012 (UTC)
 * The above discussion is preserved as an archive of the debate. Please do not modify it. Subsequent comments should be made on the appropriate discussion page (such as the article's talk page or in a deletion review). No further edits should be made to this page.