Talk:Self-creation cosmology
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[edit] Original research tag
The article has been tagged: "This article may contain original research or unverified claims" and indeed I as the article's author am the originator of the theory, yet all the work mentioned has been published in refereed journals, and developed in over 50 other author citations. Garthbarber 22:53, 31 January 2006 (UTC)
- I think you are correct (indeed Joke now agrees too). To be candid, wikipedia has a problem with people pushing Original Research in physics, so people get a bit twitchy (e.g. plasma cosmology). But published research is OK. As long as the article makes clear that this is non-standard, and perhaps adds some discussion of the degree of support it has in an amicable way, there should be no problems. William M. Connolley 09:51, 2 February 2006 (UTC).
Concur. –Joke 15:28, 2 February 2006 (UTC)
I'm not at home with all the maths by any means, but could
- One of them, the Gravity Probe B geodetic precession, is being evaluated in 2006; SCC predicts 2/3 that of the GR N-S precession, i.e. 4.4096 arcsec/yr. whereas the frame-dragging or gravitomagnetic E-W precession prediction is the same as that of GR i.e. 0.0409 arcsec/yr.
be clarified? Why is 2/3 of GR 4.4, but same as GR 0.04? William M. Connolley 15:04, 3 February 2006 (UTC).
Hi William! A good question, and one that goes to the heart of the difference between GR and SCC, the fact that SCC violates the equivalence principle. Gravitational theories with a metric, which modify the GR field equation, can be parametrised in the Post Newtonian Approximation for Tests of General Relativity. The frame dragging experiment, like most of the other tests, contains a term where in GR γ = 1 and Gm = GN, however for SCC and , so the predictions are equal. γ is the amount of space curvature per unit GM. In the geodetic precession, which directly measures curvature, the corresponding term is so the corresponding geodetic precession is the GR prediction. However the satellite is not in free fall, it is being accelerated by the scalar field force and this introduces an extra Thomas Precession is just the GR prediction, which has to be subtracted, leaving a total of the GR prediction. Garthbarber
Hm, how does the theory evade bounds on γ from, say, lunar laser ranging or the Cassini-Huygens probe? As I recall, . –Joke 21:06, 3 February 2006 (UTC)
- Umm, I was expecting that much maths in answer. On closer inspection, I see there is a distinction between NS and EW precession which I'd missed: can I suggest that for the general user, this needs clarification? William M. Connolley 21:38, 3 February 2006 (UTC).
Hi Joke! The theory is conformally equivalent to canonical GR in vacuo. Particles follow the geodesics of GR, this means that any test that measures the orbital parameters of the Moon, or spacecraft, determined from the local gravitational field, i.e. the Schwarzschild metric, will find that in both theories the predictions are the same. Only the geodetic precession measurement, which measures curvature, not by the GR geodesic orbit but by the precession of a solid gyroscope, will resolve the degeneracy in these tests.
The cosmological solution, on the other hand, does not in general assume a vacuum but a cosmological representative fluid of positive density. In this case the predictions are different, no inflation, non-baryonic DM or unkown DE, and they leave a tiny cosmological imprint (cH) on spacecraft orbits, which has been detected in the Pioneer anomaly. Garthbarber
Hi William, Thank you I will try to clarify the article for the general user. Garthbarber
Now done. I now notice the article is put in the Category: Pseudophysics at the bottom of the page.
Following the link I read: "Pseudophysics posses many, if not all, of the traits of pseudoscience, including the lack of falsifiable predictions, lack of peer review, or the blatent contradiction of well-established theory and experimental results."
As the theory is proposing a modification of GR, similar to that of the Brans-Dicke theory, that it is eminently falsifiable and being tested at this moment by the GP-B experiment, that it is published in peer-reviewed journals and does not contradict any experimental results (yet), may this be changed to "Category:Theories of gravitation" as the Brans-Dicke theory is described? Garthbarber 13:51, 6 February 2006 (UTC)
Hi Garth, you may be surprised to hear that you added the pseudophysics category. [1] It must have been inadvertently copied from somewhere. I will remove it. –Joke 14:52, 6 February 2006 (UTC)
Thanks!Garthbarber 14:57, 6 February 2006 (UTC)
[edit] Suggested improvements
I've added a short todo list.
A general discussion of key mathematical and physical features of both gtr and its competitors is currently lacking in the WP. One of the goals of WikiProject GTR is to provide much improved and unbiased discussion placing our current Gold Standard Theory of gravitation in context, and bringing out the strengths and weaknesses of gtr and its most popular competitors (including pedagogically illuminating or historically important obsolete theories) for the benefit of contemporary readers.
In general WPGTR encourages articles which begin with paragraphs written for laypersons and which (as far as possible) introduce more sophisticated ideas gradually. For example, instead of jumping right into PPN parameters, and assuming the analog of the Schwarzschild vacuum (in Schwarzschild coordinates) is known, one could consider a more elementary discussion in which one follows the model of textbooks like D'Inverno to compute predictions for the four classic solar system tests. This kind of discussion is much more likely to be accessible to bright undergraduate students who have taken a solid first course in gtr, for example.
Ideally we'd also like to try to ensure a nearly uniform notation, e.g. Landau-Lifschitz spacelike (-+++) conventions for metric theories. Notatation of covariant differentiation is a judgement call, but one should at least consider looking at other articles to see if some changes might improve the readability of this article for students who have studied similar articles elsewhere in this category.
I believe that in an encylopedia article, the standard of writing (in terms of motivation, organization, clarity, concern with notation) is higher than in a research article, where timeliness may be a more pressing concern.
Currently Brans-Dicke theory needs to be completely rewritten as per the todo list for that article. Wanting the job done right, I'd prefer to do that myself, but I'm leaving. Let me note that one of the improvements urgently needed in that article is Jordan versus Einstein frame, which could relieve burden of explaining that here, which has disrupted the flow of ideas in this article.
To point out the obvious, since this article is mostly by the most energetic proponent of the theory under discussion in the article, everyone needs to help make sure that the article remains unbaised.---CH 21:03, 17 April 2006 (UTC)
[edit] To Do List - Introduction
I have expanded the Introduction for clarification, yet would welcome other edits to keep the article unbiased.
Note: In my opinion the discussion on the two conformal frames in this article is essential to the understanding of the theory, particularly its concordance with presence observations, and the physical relationship with measurements across curved space-time. I have expanded that section accordinglyGarthbarber 06:54, 18 April 2006 (UTC)
I have added a brief overview to describe the main features of the theory before indulging in mathematics. Garthbarber 09:50, 8 May 2006 (UTC)
- Just to be clear, you are in real life G. A. Barber, who proposed "self creation cosmology" and published subsequent papers on this topic, right? It might be a good idea to state this on your user page, just to make it clear that nothing underhanded is going on here. I haven't read this article carefully, but I WP:AGF until contrary evidence. However, you should probably be aware that we have had quite a few problems recently with apparent shilling and socking by various persons trying to promote their own (usually highly cranky) theories at WP. I apologize if this has already been asked and answered--- I thought I did ask, but I can't seem to find any record of that now. I see that Joke has expressed the same conclusion (pretty obvious really) about your IRL identity in a comment on your user talk page, but you didn't take the opportunity to confirm this.---CH 11:37, 22 May 2006 (UTC)
Yes, I am the author of the initial Self Creation Cosmology papers. I have now started a Userpage.
To put your mind at rest, there are 59 SCC citations published in refereed journals with another three on the physics ArXiv alone, and I am author of only seven of these. Some of this other author citations are listed in the main article.
SCC is an alternative gravitational theory that is being tested by GP-B at this moment so we shall not have too long to wait - April 2007 - we are told, before finding out whether there is anything in it or not! Garthbarber
[edit] POV Template
I have added the POV template to the article as an indication that as far as we can tell, the article was written by a single person, who is also the originator of the SCC theory, Garthbarber (talk • contribs). This is not to say that I suspect any foul play or incompetence. On the contrary, I assume integrity and normal human competence. But the fact that the article is only written by the creator of the theory, and it is a rather complex one - not self evident by inspection, raises the possibility of human errors at various levels. We do have some published references at neutral publications, but still it would be much better to have neutral individuals presenting the theory here, as opposed to its originator, to weed out possible errors and create at least an appearance of neutrality. Once some knowledgeable independent contributors review and edit this article, it would make sense IMO to remove the neutrality template. Crum375 23:46, 26 June 2006 (UTC)
There are a small number of people working on this theory around the world, however they do not seem to be Wikipedians! There is enough material published in referred journals and on the Physics ArXiv for others to criticise. I welcome them to edit this article, but otherwise I myself cannot do much about the POV problem at this stage. I have just highlighted a potential problem with Type Ia supernovae hoping to improve the article's neutrality. Garthbarber 08:10, 1 July 2006 (UTC).
What is your own speculative explanation for the supernovae's apparent increasing brightness over time? Crum375 13:05, 1 July 2006 (UTC)
The problem is nobody has a definite model for the Type Ia SN, they are hydrogen deficient and show a strong Si II line. The best agreement between the theoretical and observed spectra is obtained by modeling the explosion of an accreting carbon-oxygen white dwarf in a close binary system. The white dwarf accretes material from its companion until core carbon burning begins and it deflagrates, with the shock front moving slower than local sound speed. The light curves of local Type Ia are sufficiently similar that it is thought they can be used as standard candles.
At z ~ 1 these candles appear dimmer than expected, hence the inference of cosmic acceleration and DE on which the present model is based. It is generally acknowledged that the foundations of that base are rather shaky however!
At even higher red shift z > 1 their apparent magnitudes become brighter again than expected, which gives a handle on how DE behaves, if the model is right.
The linear expanding freely coasting model fits the z ~ 1 SN Ia remarkably well, and as SCC mimics the linear expanding model this gave me a false hope, however the difference is the linear, freely coasting model has hyperbolic space, k = -1, whereas SCC is linearly expanding but with spherical space, with k = +1. This should make the SN brighter in SCC than they appear in the k = -1 model, and hence they must be less luminous than the model predicts.
But why should the SN Ia be less luminous in the past than the model suggests? Here I am 'hand waving', but reasons could be - a selection effect as most distant SN are detected after peak luminosity, and the further away they are the more might be missed. Or at high z the progenitor stars might well be expected to have less metallicity than more recent ones. As you said, these are speculations only, but perhaps no more so than a bland acceptance that their luminosities don't change over such cosmological time scales. Garthbarber 19:16, 1 July 2006 (UTC)