Talk:Inflation (cosmology)/Archive 5

When "prediction" is used instead of "retrodiction"
When "prediction" is used instead of "retrodiction", this appears to be an issue throughout cosmology as reflected here on Wikipedia. Might it help the credibility of cosmology with the public to systematically distinguish when something is actually a prediction, as compared to a retrodiction? For example, if I produce a climate model that better predicts the climate ten years out, as compared to the other popular models, my model gains credibility. But for the most part, all the models "predict" the climate from ten years ago. That's not as impressive because we software developers are pretty good at getting our software to generate required outputs, and that says very little about the predictive ability of our work. (I was a programmer in the McDonnell Douglas Helicopter Co simulation department in the 80s for the AH64 Apache Helicopter.) For example, if the big bang model "predicts" the initial abundances, but that is really a series of repeated retrodictions designed to meet the required observed abundances, then for many people, that builds less credibility for the model than would an actual prediction. So, might it help with credibility for Wiki's many cosmology articles to employ "retrodiction" where appropriate? Bob Enyart, Denver KGOV radio host (talk) 18:00, 17 January 2020 (UTC)

Retrodiction? Never heard this term before. 192.88.124.40 (talk) 16:53, 3 March 2020 (UTC)

I've heard it, but am not sure it applies here. It's perfectly possible to predict about the past, because even if things have already happened, that doesn't mean one already knows about them. A theory might predict that if a particular inquiry is made about the past, a certain answer will be obtained. I wouldn't advocate the use of the word ‘retrodict’ for a general audience anyway, there are are usually better words to use like ‘explain’ for example, depending on the specifics. — Preceding unsigned comment added by 77.61.180.106 (talk) 05:57, 15 January 2021 (UTC)

I've gone back through the article searching for the word ‘predict’ and I think he's right after all. The article contains a number of instances where I can see even at a glance that the word ‘predict’ is probably used wrongly and the entire article should be screened to make sure that every instance of ‘predict’ actually refers to new data that was obtained after the relevant theory was constructed. — Preceding unsigned comment added by 77.61.180.106 (talk) 06:05, 15 January 2021 (UTC)

Semi-protected edit request on 27 May 2021
Add a reference https://arxiv.org/abs/1306.4213. From: sometimes called the exotic-relics problem, says that if the early universe were very hot, a large number of very heavy To: sometimes called the exotic-relics problem, says that if the early universe were very hot, a large number of very heavy Rainspires (talk) 20:38, 27 May 2021 (UTC)
 * ❌. Source (arXiv) is a considered unreliable, author does not seem to be subject-matter expert. ◢  Ganbaruby!   (talk) 03:44, 28 May 2021 (UTC)
 * The first author has published peer-reviewed papers on magnetic monopoles and cosmological implications thereof in reputable journals (see his arxiv history: EPJC, PRL, ...) and is a professor of physics at the University of Valencia, one of Spain's most prestigious. While this particular paper is not (yet?) peer-reviewed, he certainly qualifies as a subject matter expert. (I am not in any way affiliated or acquainted.) Advolvens (talk) 23:06, 9 June 2021 (UTC)
 * The existence of heavy magnetic monopoles with masses above $$10^{16}$$ GeV is one of the prediction of GUT theories. Rainspires (talk) 18:25, 9 June 2021 (UTC)
 * ArXiV is a reliable source for the provenance of the paper. The authors are SMEs and both are working with high profile international collaborations in the field. I don't have the background to judge their work, but surely when a full professor published in excess of 200 papers there is some credibility. --Shmuel (Seymour J.) Metz Username:Chatul (talk) 01:24, 10 June 2021 (UTC)

Vaas book
The book by Rudy Vaas appears on Google Books with a publisher, an ISBN, etc:. It's also on Amazon:. However, it doesn't appear to be actually available for purchase anywhere, and I don't find a copy in a quick search of a couple of university libraries, so it must be a very limited run. The information on the Google Books link should give us what we need to properly cite. --Amble (talk) 17:27, 11 April 2022 (UTC)
 * I don’t see it even searching Worldcat. It’s supposedly by Springer, the publisher still exists an everything else they’ve ever published is recorded in their website. And per WP:SAYWHEREYOUGOTIT people are getting it from this draft version, not the published version (if that is anything more than just an ISBN). Umimmak (talk) 18:33, 11 April 2022 (UTC)
 * OK, apparently having an ISBN doesn't mean much, and you're right, Springer doesn't show it. Do the Google Books and Amazon pages get automatically populated from the ISBN even if no book is published? The draft seems to be cited in various papers as a chapter of the book (even though there doesn't seem to be a book). Perhaps it's best in that case to manually format the citation instead of using a template. --Amble (talk) 18:56, 11 April 2022 (UTC)
 * I mean, I thought was fine the way I had it before, using Unpublished draft manuscript, was fine? But I think the best thing to do is to find something else Steinhardt has written (outside of SciAm) that speaks to him becoming a critic of the idea? Unless this particular draft manuscript is particularly influential, it seems strange to even cite in the first place? And perhaps, ideally, a secondary source noting how he has become a critic? Umimmak (talk) 19:45, 11 April 2022 (UTC)
 * I edited believing that there actually was a book, based on the ISBN, Google Books page, and Amazon listing. But there doesn't seem to actually be a book after all. I'm happy to revert. --Amble (talk) 19:50, 11 April 2022 (UTC)

Hypothesis / Theory
The first introductory sentence of the article calls the Cosmic Inflation a "theory", making a false impression that it is an established scientific fact. There is still a debate about the validity of this hypothesis in the scientific community. Calling something a Scientific theory requires a much higher level of validation and experimental/observational testing. The phrasing is also in contrast with articles in other languages: German, French, Italian and Russian versions in different ways, but all mention the hypothetical nature of the subject at the outset.

I suggest changing the wording completely - by calling it a "hypothesis" or a "model". Or, at least, add a clarification that it "...is a theory that hypothesizes a period of exponential expansion of space...". — Preceding unsigned comment added by Kanishev~enwiki (talk • contribs) 18:38, 14 February 2022 (UTC)


 * @Kanishev~enwiki
 * I agree. I think the most accurate description of the current situation is that it "is a collection of theoretical models that hypothesized a period of exponential expansion of space...". I hope someone would change the current language in the article.
 * CA2MI (talk) 17:16, 3 October 2022 (UTC)
 * All theories are provisional. While there is certainly research exploring alternative models, and some disturbing data from Webb, there is too much evidence supporting the old "Big Bang" and newer hyper-inflationary models to label them as mere hypotheses. --Shmuel (Seymour J.) Metz Username:Chatul (talk) 11:41, 4 October 2022 (UTC)
 * All theories are provisional. While there is certainly research exploring alternative models, and some disturbing data from Webb, there is too much evidence supporting the old "Big Bang" and newer hyper-inflationary models to label them as mere hypotheses. --Shmuel (Seymour J.) Metz Username:Chatul (talk) 11:41, 4 October 2022 (UTC)