Talk:Black hole/Archive 17

Cause-effect order stated the wrong way around (?)

The current article text contains:

"This is different from other field theories such as electromagnetism, which do not have any friction or resistivity at the microscopic level, because they are time-reversible."

I think the friction or resistivity actually causes the time-reversibility, instead of the other way around. So I propose:

"This is different from other field theories such as electromagnetism, which do not have any friction or resistivity at the microscopic level, and are therefore time-reversible."

Any objections?Redav (talk) 22:47, 12 May 2022 (UTC)

@Redav: Can you find a source to support either wording? Auguel (talk) 14:14, 13 May 2022 (UTC)

@Auguel: Maybe I could if I searched long enough (the subject is not my specialism), but the matter strongly appeals to my general understanding of physics (and I do know a thing or two about that), saying that the cause is first and the consequence is second. In my view, frictionlessness is the cause and time-reversibility is a consequence of it. Hence my proposal.Redav (talk) 15:20, 13 May 2022 (UTC)

Semi-protected edit request on 20 December 2022

Siddarthkoushik (talk) 14:15, 20 December 2022 (UTC)hii I want write short answer for students who want it short answer for black hole

 Not done: This template must be followed by a complete and specific description of the request, that is, specify what text should be removed and a verbatim copy of the text that should replace it. "Please change X" is not acceptable and will be rejected; the request must be of the form "please change X to Y". - DVdm (talk) 15:01, 20 December 2022 (UTC)

edit request

can someone add a picture of the Sagittarius A* black hole. BrokeStudent69 (talk) 02:32, 5 January 2023 (UTC)

Light "cannot escape a black hole"

"no particles or even electromagnetic radiation such as light — can escape from it."

I believe it to be the case that photons do not touch a black hole, and simply go past it. Light always goes in straight line, but black holes bend spacetime and therefore cause light to go "around" the black hole; light does not touch it. Is this incorrect? --94.15.6.115 (talk) 14:26, 29 March 2022 (UTC)

Arguably incorrect. Light with a path towards a Black Hole (specifically, towards its center) will arguably pass through the Event Horizon. I write "arguably" because a Black Hole is a space-time singularity and light will take an infinite time to actually pass the EH, with corresponding (infinite) red-shift (if it could be observed). So, while it is definitely incorrect to say that all light goes around a BH, it is also the case that no light has yet gone through a BH's Event Horizon. It is light passing *near* a BH that is lensed (bent). (With the understanding that the Event Horizon is a theoretical surface and has no material existence, nothing to 'touch' there.)207.155.85.22 (talk) 10:35, 16 May 2022 (UTC)

Hi all - not my field whatsoever, but I have read a bit about Hawking raditation. The beginning part of this wiki states that no electromagnetic radiation is emitted from a black hole. Should this be highlighted to show that, within the theory of Hawking radiation, this might not be completely true? Jamzze (talk) 10:25, 15 May 2021 (UTC)

It does not say that no radiation is emitted. It says that none escapes (from inside). It then says that Hawking radiation is emitted from the horizon. This is correct according to mainstream theory.Weburbia (talk) 12:18, 15 May 2021 (UTC)

Thanks. There appears to be a misconception going around that light is gravitationally pulled into a black hole. The wording here brings that to mind and doesn't seem entirely clear. — Preceding unsigned comment added by 94.15.6.115 (talk • contribs) 15:26, 29 March 2022 (UTC) Are black holes real https://astrophile0.space/are-black-holes-real/ — Preceding unsigned comment added by Utka05 (talk • contribs) 08:56, 7 January 2023 (UTC)

Event Horizon

The event horizon could be a optical illusion because it may not have mass. Since the beyond the event horizon is near instant absorbtion into the singularity. The Event Horizon might not have mass and therefore could be a optical illusion. Randomsmartkid (talk) 14:51, 3 March 2023 (UTC)

Black holes must be hot inside

There is a continual entry of matter to excite. How can hawking radiation be emitted if they are not Hot? 152.76.2.2 (talk) 23:56, 16 January 2023 (UTC)

Black holes could also be stars that are so big that the gravitational pull is strong enough to pull back light but not strong enough somehow to collapse the star on itself. This is the "Dark Star" theory Randomsmartkid (talk) 14:53, 3 March 2023 (UTC)

risk to earth

Today I wanted to add the following to the introduction:

There is no risk for earth to be destroyed by a black hole<ref>{{Cite web|url=https://science.thewire.in/aerospace/earth-black-hole-threat/|title=Can Earth Be Affected by a Black Hole in the Future?|work=[[The Wire (India)]]|date=2019-08-02|access-date=2022-12-16}}</ref> within the next four billion years.<ref>{{Cite web|url=https://www.ibtimes.com/earth-danger-getting-devoured-black-hole-2820077|title=Is Earth In Danger Of Getting Devoured By A Black Hole?|work=[[International Business Times]]|date=2019-08-30|access-date=2022-12-16}}</ref>

It was removed as "not needed", but I believe this point to be the most relevant of all. Best regards,--Vergänglichkeit (talk) 16:23, 16 December 2022 (UTC)

I don't think we need to include a negative. Zaathras (talk) 16:41, 16 December 2022 (UTC)

I reverted it. If there is no risk, why mention it? The article is not about Earth, and there is no black holes close to Earth, and there is no real life scenario where black holes can affect Earth. No need to include speculations. Artem.G (talk) 17:34, 16 December 2022 (UTC)

@Artem.G Well humans are curious beings so they like to explore things they don't know properly about. If you are uncomfortable seeing this then just don't. Tryna learn (talk) 03:05, 5 April 2023 (UTC)

Your comment has no applicability to this 4-month-old discussion. This is an encyclopedia, not an after-school activity. Zaathras (talk) 04:07, 5 April 2023 (UTC)

Semi-protected edit request on 27 April 2023

Please undo this edit with the rationale that it adds nothing of use to the article. It's another pointless WP:PROSELINE addition, with no apparent significance or context for the reader. 35.139.154.158 (talk) 21:03, 27 April 2023 (UTC)

 Not done: The editor seems to know what they are doing and its significance is that 2 things were viewed together for the first time. Also WP:PROSELINE is an essay. ― Blaze Wolf^Talk_{Blaze Wolf#6545} 21:06, 27 April 2023 (UTC)

Reopening. Would like to see consensus for this addition. It's a bad edit. This editor has a history of these bad edits. "Something was presented" gives no useful information to the reader. Edit: and note that this would be the next normal step in a BRD cycle, so it should be otherwise uncontroversial at the moment. 35.139.154.158 (talk) 21:12, 27 April 2023 (UTC)

Give me a policy based reason why the edit should be reverted other than simply "its a bad edit". ― Blaze Wolf^Talk_{Blaze Wolf#6545} 21:22, 27 April 2023 (UTC)

@Drbogdan: Pinging the editor who's edit is in discussion ― Blaze Wolf^Talk_{Blaze Wolf#6545} 21:23, 27 April 2023 (UTC)

"Something was presented" gives no useful information to the reader – what kind of assertion is this? If your worried about attribution, it's available in the cite. The sentence provides useful information about the state of observational evidence in the section about observational evidence. small jars tc 21:31, 27 April 2023 (UTC)

This. The section is about observational evidence, and the addition shows the current state of advancement of black hole imaging. I see nothing particularly wrong, though expanding on this when possible would be useful. — Huntster (t @ c) 00:24, 28 April 2023 (UTC)

@Artem.G, Blaze Wolf, FlightTime, Huntster, SmallJarsWithGreenLabels, and Viriditas: - FWIW - as OA - seems the edit at issue, along with several related WP:RS references, is worthy - it's *entirely* ok with me to improve the text of course - also - please WP:AGF and/or WP:NPA - Thanks - iac - Drbogdan (talk) 22:25, 27 April 2023 (UTC)

References

different formula astronomical distance

In his book the Quantum Theory of Gravitation (2003) the russian scientist Vasily Yanchilin gives arguments opposing existence of black holes. Pleas add this book to the literature and more: Explain whether he is right or wrong with solid argumentation. (Jitso Keizer, www.janjitso.blogspot.com for more info). 194.171.56.13 (talk) 09:17, 6 July 2023 (UTC)

Incorrect citation

The citation for the M87 black hole image does not appear to link to the correct article. Should be https://doi.org/10.3847/2041-8213/ab0e85 — Preceding unsigned comment added by 220.253.241.149 (talk) 04:22, 27 June 2023 (UTC)

Which citation are you referring to? There are a few different citations about M87. - Parejkoj (talk) 17:33, 6 July 2023 (UTC)

F152, JJ Cluster Colony, Narela

F152, JJ Cluster Colony, Narela 106.210.59.75 (talk) 16:17, 21 July 2023 (UTC)

F152, JJ Cluster Colony, Narela

F152, JJ Cluster Colony, Narela 106.210.59.75 (talk) 16:17, 21 July 2023 (UTC)