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 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 Template:10^ seconds to between Template:10^ and Template:10^ 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

File:History of the Universe.svg

which in a tiny legend indicates that the inflationary period occurred before the age of the universe was Template:10^ 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 Template:Tl. 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)

@Skierpage Let me try to explain why I am be disagreeable on this point. Two extensive secondary sources on inflation are

• The 2024 Particle Data Group review of inflation.
• Chapter 11 of Peacock, J. A. (1999). Cosmological physics. Cambridge university press.

Neither of these sources discuss duration. These physics experts could have included a duration if it was notable. They did not.

Peacock says things like Template:Tq. Perhaps this sounds strange to a non-physics expert, but many different theories of inflation are compatible with the observational constraints. Time is just a "parameter", that is a value to be varied within the model. The number itself does not necessarily have meaning.

Having said that, specific models, especially simple ones for textbooks or highly developed ones like Lamba-CDM may have numbers we can call durations. So while we can't say the "inflationary epoch lasted ..." may be able do say something in the context of particular sources. Johnjbarton (talk) 02:47, 1 June 2025 (UTC)

I added a paragraph to Overview with content that includes a duration estimate. (This source is one of many that describe inflation as "pre-Big Bang")

File:Yes check.svg Done Johnjbarton (talk) 17:47, 4 June 2025 (UTC)

Criticisms

The Criticisms section contains material that is 10-40 years old. It should be updated. Johnjbarton (talk) 19:07, 4 June 2025 (UTC)