Talk:Time travel

replacement for wretched wording and markup

   A colleague (who didn't take the trouble to encourage constructive discussion by even saving -- for those who care who the colleague is or when they held forth -- the trouble of searching the edit history) did add to Time travel#Tourism in time the following comment markup (to which i've added meta-markup, on this talk page, trying to make the markup display in a more intuitively clear way here):

"This picture would explain why we haven't been over run [sic]

<!-- several people have tried to edit this, but note that it says "over run" rather than "overrun" in the original essay on Hawking's website, and direct quotes should match the original source so please don't change it -->

by tourists from the future."

   The colleague's concern for non-misrepresentation is praiseworthy, even tho the wording "have tried to edit" reeks too much of the Inquisition or the Klan, and the typographic travesty that is their solution may not even be appropriate for some critical edition of Hawking's works. Here -- leaving behind the pedants' concern about who (Hawking, an editor, a typesetter?) is responsible for the inappropriate internal space -- is an encyclopedia-appropriate version of the passage:

"This picture would explain why we haven't been [overrun] by tourists from the future."

It's literate, harmless, almost devoid of distraction, and not significantly better nor worse than

Stephen Hawking says that this picture would explain why our times haven't been overrun by "tourists from the future."{{cn|date=January 2015}}

--Jerzy•t 04:21 & 07:05, 3 February 2015 (UTC)

Why two "physics" sections?

I don't understand why there are two top-level sections for addressing the concept in physics: "Time travel in physics" and "Forward time travel in physics". Surely the latter is a subtopic of the former? Or if they are kept separate, shouldn't the former be "Backward time travel in physics" for symmetry? Reading the former section with all of its uncertainty and speculation – when we know that forward time travel is possible – was confusing until I found the latter section tucked below it as if an afterthought.-Jason A. Quest (talk) 23:55, 28 January 2021 (UTC)

The first section is more precisely titled "Arbitrary time travel in physics" (in the sense of an arbitrary point in spacetime in the past or future) while the second section is more precisely titled "Time-dilation forward time travel" (as opposed to using time dilation for backward time travel such as through a wormhole). However, the current titles are perfectly clear if you read the sections instead of just reading the titles. WikiPacer (talk) 04:07, 23 March 2021 (UTC)

Those are not the actual section headers in this article. -Jason A. Quest (talk) 20:40, 23 March 2021 (UTC)

The concept of a time machine likely has stand-alone notability

Right now this redirects here and never had a separate article on English Wikipedia (I noticed it does on pl wiki, and several others; here's the wikidata entry [1]). And here's an interesting source: [2]. I haven't done much lit review but there are plenty of uses of the term, some pretty close to the basic concept (consider [3], [4], [5], [6], [7], [8]... the term is actually used a lot in physics!), but this one is decent, and here could be an interesting article on a relatively major topic related to fiction (and even science??) that could be created... would anyone be interested in working on it? The topic has a stand-alone entry in the SF encyclopedia: [9], separate from their entry on time travel. Ping User:Haleth, User:Toughpigs - this time not re deletion/rescuing, but maybe we can try to write a new entry together for a change? Any sources you could throw at me here would be appreciated. (Btw, I checked and the concept sadly does not seem to have a stand-alone entry in The Greenwood Encyclopedia of Science Fiction and Fantasy: Themes, Works, and Wonders nor The Mammoth Encyclopedia of Science Fiction). --_{Piotr Konieczny aka Prokonsul Piotrus| reply here} 03:12, 24 February 2021 (UTC)

I think the concept of "time machine" is independently notable and verifiable as a concept, both as a scientific theory and as a well known trope in works of fiction. I suspect the reason why it has never had a standalone article on Wikipedia is because the existence of Time travel in fiction as an article, which seems to be based around the seminal 1895 work as the progenitor of the trope. The issue I can identify here...will a standalone "time machine" end up being a Redundant content fork of either article in terms of content? Most of the academic sources certainly overlap with the sort of content we can find in time travel, and portrayals of time machines in fiction certainly falls under Time travel in fiction. If we are satisfied that it falls under an acceptable type of content forking and spinning it out would be appropriate, the question then becomes, should "time machine" be isolated and discussed as a concept unto itself by drawing from both the scientific studies from the time travel article and the fiction-oriented sources from time travel in fiction, possibly cutting and pasting all that information into the proposed article? Or maybe keep the status quo as it is, but expand the time machine aspect on both articles with the sources you have found? Haleth (talk) 14:51, 24 February 2021 (UTC)

Potential narratives about backwards time travel that may pre-date the 18th century

There are 2 pages that talk about narratives in which travelling back in time is mentioned. The page Mohave traditional narratives as well as Journey to the West in the "Sequels" section. I'm not absolutely sure that these 2 time travel narratives are not later-date additions to Mohave folklore and to the "Supplement to the Journey to the West" book, though. Is it certain that they're not? — Preceding unsigned comment added by Dominic inquisitive (talk • contribs) 22:24, 29 August 2021 (UTC)

Please sign all your talk page messages with four tildes (~~~~) — See Help:Using talk pages. Thanks. - DVdm (talk) 08:40, 30 August 2021 (UTC)

Semi-protected edit request on 30 December 2021

i want to make the definition more clear LUTTAPI444 (talk) 13:27, 30 December 2021 (UTC)

 Not done: it's not clear what changes you want to be made. Please mention the specific changes in a "change X to Y" format and provide a reliable source if appropriate. DanCherek (talk) 13:45, 30 December 2021 (UTC)

Presentism vs Eternalism

This section needs more clarity and references. The paragraph "Presentism in classical spacetime deems that only the present exists; this is not reconcilable with special relativity, shown in the following example: " merely asserts the incompatibility of presentism with special relativity. But that assertion is the point of contention. I find the phrase "Presentism in classical spacetime" to be ambiguous. It needs some definition. Also, the argument for eternalism appears to be a form of that of Putnam, H. 1995. Time and Physical Geometry. In Mathematics, Matter and Method, Philosophical Papers, Vol. I., 2nd edition, pp. 198-205. Cambridge University Press. I suggest that reference be added. (Personally I find Putnam's argument unpersuasive and flawed).Theophilus71 (talk) 18:15, 15 January 2022 (UTC)