Talk:Cosmic inflation

Duration

The section on Duration has indirect citation to

• Liddle, Andrew; David Lyth (2000). Cosmological Inflation and Large-Scale Structure. Cambridge. ISBN 978-0-521-57598-0.

but the section of that book that discusses the 60-e-fold factor is about a model BGT that is not considered viable. The other ref in the footnote is incorrect. Johnjbarton (talk) 15:39, 16 August 2024 (UTC)

There is no "Duration" section any more! The word "duration" no longer appears in the article. -- Skierpage (talk) 04:32, 30 May 2025 (UTC)

This summer

There's a note (note e) that mentions "this summer" and "July" as if Wikipedia is a news source. I think Wikipedia must change. At the least, editors should be told not to use terms like "this summer", "recently", "until now", etc. etc. etc. My opinion is that no edit containing such poorly thought out verbiage should be accepted, but perhaps as a start, when an editor uses such poor judgement, it should be flagged. My guess is that note e was written in 2012, over a decade ago. Since CERN DID announce discovery of the Higgs particle (i.e. a 5 (?) sigma mass|energy spike at ~126 GeV/c², with follow-on confirmation that the particle's properties are as expected) this note should be up-dated (or removed). Two other complaints: the lead contains way too much (imho) about the awards of the originators (Kavli, Dirac, and Breakthrough prizes). These belong in the respective biographies, not in the lead ad nauseam. Condense them. Finally, if I can do my arithmetic, 7.7 plus 5.4 billion is not 13.8 billion. Seems to me someone can't add. (If Inflation occurred 7.7Gy after BB and 5.4Gy ago, it follows that the BB was 13.1Gy ago (or Inflation lasted for 600My) and this is WRONG.) I note that the "Overview" is not an overview but a brief history. I note that the claim that our observable universe is a "patch of a larger unobservable universe" is vacuous - if you can't, in theory, observe it, or its causal effects, then it ain't science. And there are a variety of other problems that are glossed over in the lead. For instance, quantum gravity *must* have had a huge effect during (early) inflation, so claiming that inflation is "accepted" is a bit of a stretch. Also, the claim that most physicists accept inflation NEEDS A reliable citation. And since "most physicists" are NOT experts in the early universe, is this really important? How about using a more appropriate term like "cosmologists"? Finally, I have a problem with the implied claim that the (non-inflationary) Hot Big Bang model is "standard". It is not, and hasn't been for decades. How about, oh just as a suggestion, you actually mention the standard model? (which includes inflation). In case you're unaware of it, it's the Λ-CDM model (which, astonishingly, is nowhere to be found in this article!!!). Anyway, I'd like to see the "overview" completely rewritten into an actual overview. One other thing that's missing in the text is numbers: like when did it start, how long did it last, what was the initial size of the OU, and what size was it when it ended, same with temperature. And no, this should not be sprinkled around here and there. ... Two questions I have: is Dark Energy a necessary assumption of the theory? and is Dark Matter a necessary assumption of the theory? If not, are they necessary results? (I guess that's 4 questions, LOL)98.17.42.35 (talk) 21:01, 6 December 2024 (UTC)

I cleaned up some of this. Johnjbarton (talk) 04:14, 7 December 2024 (UTC)

This article no longer says when Cosmic Inflation started and how long it lasted!?

In a revision on 2024-08-16, Johnjbarton deleted the essential sentence from the introductory paragraph

The inflationary epoch is believed to have lasted from 10⁻³⁶ seconds to between 10⁻³³ and 10⁻³² seconds after the initial moment of the Big Bang.

The edit summary was "Delete sentence that does not reflect content in the article". Indeed, at that time and thereafter there seems to be no explanation of the start and duration of cosmic inflation, let alone citations, later in the article. The duration is only implied by the image File:History of the Universe.svg

which in a tiny legend indicates that the inflationary period occurred before the age of the universe was 10⁻³² seconds. It is unfortunate that this article does not motivate or cite the start and duration of the inflationary period; amongst many other deletions Johnjbarton deleted a "Duration" section but that didn't seem to state the duration. But it is clearly ridiculous for an encyclopedia article about a period not to state when the theory posits its start and duration! Indeed, the Inflation (disambiguation) page provides a better summary of Cosmic inflation theory than this article,

the inflationary epoch lasted from 10⁻³⁶ seconds after the Big Bang to sometime between 10⁻³³ and 10⁻³² seconds

I'll restore the sentence and look for a template {{article summary is right but not backed up by article contents}}. I'm no physics expert but surely dozens of experts in the field have written overviews of cosmic inflation theory that state its start and duration -- Skierpage (talk) 05:22, 30 May 2025 (UTC)

Please post a reliable source for the "duration" and I will add content to the article. However I will remove any unsourced claims. Please see WP:BURDEN. Johnjbarton (talk) 14:42, 30 May 2025 (UTC)