Talk:Black hole

Write on the main table: smallest observed so-and-so, smallest theorized so-and-so // biggest observed so-and-so, biggest theorized so-and-so

• https://news.osu.edu/black-hole-is-closest-to-earth-among-the-smallest-ever-discovered/

Write both observed AND theorized (if you hide theory vs data science doesn't evolve).

Intro paragraph

Replace the dashes for commas. Introduce John Michell and Pierre Simon in the beginning of the second paragraph. Meaning put the subjects who discovered it first.

It says nothing can escape

Hawking radiation is mentioned to escape despite it saying nothing escaped 152.76.2.2 (talk) 23:51, 16 January 2023 (UTC)

I think the article pretty clearly states that the radiation is emitted outside the event horizon. What would you suggest make that clearer? ——Digital Jedi Master (talk) 01:27, 18 July 2023 (UTC)

Then how do dark light/dark matter can escape 2409:40F2:1A:6D1C:2509:203B:A4E9:F301 (talk) 16:00, 4 March 2024 (UTC)

They don't 2.24.145.21 (talk) 23:28, 28 August 2024 (UTC)

English?

The passage

"Scholars of the time were initially excited by the proposal that giant but invisible 'dark stars' might be hiding in plain view, but enthusiasm dampened when the wavelike nature of light became apparent in the early nineteenth century, as if light were a wave rather than a particle, it was unclear what, if any, influence gravity would have on escaping light waves."

I hope that someone knowledgeable about the subject can rewrite this, but in English.

This seems pretty clear to me, if not intentionally flowery and pretentious, ie. 'enthusiasm dampened'. Someone wanted to sound like Shakespeare. 57.135.233.22 (talk) 15:31, 7 June 2024 (UTC)

Littered with the assumption of singularity, the article needs a major rewrite.

In a paper released 5 Dec 2023 (https://arxiv.org/pdf/2312.00841.pdf, 'Do Black Holes have Singularities?', Prof. R. P. Kerr, University of Canterbury, Christchurch) states: 'There is no proof that black holes contain singularities when they are generated by real physical bodies'. The paper was also discussed on 8 Jan 2024 by popular astrophysicist YouTuber Anton Petrov here: https://www.youtube.com/watch?v=xnlIjiyhAWE.

Also, this article makes mention of quark degeneracy pressure (although without a wikilink) and quark stars, yet makes no mention of the closely related strange star and strange matter theories, even though the article does mention the surely even more speculative preon stars, (preons are hypothetical point particles, conceived of as sub-components of quarks and leptons).

I also suggest linking to QCD matter, Quark–gluon plasma.

Also noteworthy, CERN claims to have created matter '30 to 50 times as dense as an ordinary nucleus': https://home.cern/science/physics/heavy-ions-and-quark-gluon-plasma. MathewMunro (talk) 18:30, 6 January 2024 (UTC)

Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "http://localhost:6011/en.wikipedia.org/v1/":): {\displaystyle z \sim 7}

That error appears in the Gravitational Collapse section. I don't know what it means or how to fix it. Clockiel (talk) 02:50, 23 March 2024 (UTC)

I saw the same thing, but it seems to have fixed itself now. –CWenger (^ • @) 04:07, 23 March 2024 (UTC)

Semi-protected edit request on 9 April 2024

Please remove this statement: "Michell referred to these bodies as dark stars.[12]". The source given is a blog article on the Royal Society website. I am the author of the blog and wish to have this statement removed as Michell does not explicitly use the term 'dark star'. 'Dark stars is a paraphrasing used in my blog not a direct quote from the article by Michell discussed in the blog.

For the same reason remove from the etymology section this statement: "John Michell used the term "dark star" in a November 1783 letter to Henry Cavendish,[62]" again the source given is my blog post. RoyalSocietyArchivist (talk) 11:14, 9 April 2024 (UTC)

 Not done: The two sources cite blogs from different authors. Unless you changed your first and last name between 1979 and 1984, the statements will be kept. '''[[User:CanonNi]]''' (talk|contribs) 12:06, 9 April 2024 (UTC)

My mistake regarding the citation [12] for the first statement which I incorrectly identified as being my blog post. However i still believe that the statement "Michell referred to these bodies as dark stars [12]" is not backed up by a correct citation. Having reread the article by Simon Schaffer given as citation at [12] he does not credit John Michell with using the phrase 'dark star' either. Schaffer's article can be accessed free online here if you wish to confirm this: [1]

Please remove the second statement I identified, in the etymology section: "John Michell used the term "dark star" in a November 1783 letter to Henry Cavendish" [62] or remove/replace citation [62] referring to my blog post. The term "dark star" does not appear in Michell's letter to Henry Cavendish discussed in my blog and published in the Philosophical Transactions of the Royal Society as "On the means of discovering the distance, magnitude, &c. of the fixed stars, in consequence of the diminution of the velocity of their light, in case such a diminution should be found to take place in any of them, and such other data should be procured from observations, as would be farther necessary for that purpose. By the Rev. John Michell, B.D. F.R.S. In a letter to Henry Cavendish, Esq. F.R.S. and A.S" [2]https://doi.org/10.1098/rstl.1784.0008

I have sought other potential sources where Michell may have used this phrase - it does not appear in any documents identified in the Royal Society archive or in Michell's correspondence with Cavendish associated with the final letter that was published in the Philosophical Transactions in 1783. The paper 'John Michell and Henry Cavendish: Weighing the Stars' by Russell McCormmach which is referenced by Simon Schaffer, in turn refers to letters between Cavendish and Michell at Chatsworth Archive who hold Henry Cavendish's papers. I have enquired with their archivist who has checked all 11 letters between Michell and Cavendish in their collection , none use the term "dark star". This can be verified by consulting the published correspondence of Henry Cavendish [3]https://books.google.co.uk/books/about/Cavendish.html?id=XpyvPTRwLoQC&redir_esc=y RoyalSocietyArchivist (talk) 10:09, 16 April 2024 (UTC)

Hi and thank you for clarifying. I would like to apologize for my original response and will look into this shortly. '''[[User:CanonNi]]''' (talk|contribs) 10:14, 16 April 2024 (UTC)

Thank you, I appreciate you taking the time to investigate my request. RoyalSocietyArchivist (talk) 15:04, 16 April 2024 (UTC)

@CanonNi, is there any updates on this request? I've been running around implementing and closing requests today. ABG (Talk/Report any mistakes here) 12:49, 29 May 2024 (UTC)

@Irltoad, this request has gone stale, and I can't grasp where did the discussion died out. ABG (Talk/Report any mistakes here) 09:50, 30 May 2024 (UTC)

 Done I removed it since it failed verification. Feel free to restore if you disagree. M.Bitton (talk) 15:29, 30 May 2024 (UTC)

Hi, I'd like to repeat my request that the following statement be removed "John Michell used the term "dark star" in a November 1783 letter to Henry Cavendish" the citation [61] is to a blog post I wrote where this claim is not made. Nor does the term appear in the referenced letter by Michell to Cavendish published in the Royal Society transactions. Please see my additional comments above about research into possible other sources I investigated. If the statement is not removed please remove the citation to my blog post and cite an alternative to back this up. RoyalSocietyArchivist (talk) 09:27, 14 June 2024 (UTC)

 Partly done: Since the statement doesn't seem to be a huge issue like in BLPs I'm going to place a template and call it a day. ABG (Talk/Report any mistakes here) 00:42, 21 June 2024 (UTC)

Please start a new section next time. ABG (Talk/Report any mistakes here) 00:44, 21 June 2024 (UTC)

Semi-protected edit request on 17 April 2024

This sentence makes no sense

Instead, spacetime itself is curved such that the geodesic light travels on never leaves the surface of the "star" (black hole).

Please remove it or correct it. Thank you. (I suspect that the word "and" is missing after "on", but I do not have the necessary physical expertise and no source is provided.)2A00:23C6:54AD:5701:8844:23A2:9B53:453B (talk) 10:24, 17 April 2024 (UTC)

The sentence is correct as written: the geodesic itself never leaves the surface. - Parejkoj (talk) 16:11, 17 April 2024 (UTC)

I made a small grammatical change to the sentence that might help to improve the clarity- others can check and see if you agree with the change. Aldebarium (talk) 15:14, 8 May 2024 (UTC)

Semi-protected edit request on 1 June 2024

Please change

“The photon sphere is a spherical boundary of zero thickness in which photons that move on tangents to that sphere would be trapped in a circular orbit about the black hole.”

to

“The photon sphere is a spherical boundary of in which photons that move on tangents to that sphere would be trapped in a non-stable but circular orbit around the black hole, see Cramer 1997.

References

 More or less done. See [4]. - DVdm (talk) 13:21, 2 June 2024 (UTC)

Does light slow down or is it the emission of light that is slowed?

The section on "Formation and evolution" contains the following sentence:

Light from the collapsing material takes longer and longer to reach the observer, with the light emitted just before the event horizon forms delayed an infinite amount of time.

This statement has me scratching my head a little, because light moves at the same velocity regardless. It seems like it should be the (externally-viewed) emission of the light that is slowed (and red shifted) by time dilation. Praemonitus (talk) 16:20, 9 August 2024 (UTC)

non technical spelling error

int the alternitives section when talking about singularities the word artifacts is spelled incorrectlyp 108.29.69.127 (talk) 23:22, 7 November 2024 (UTC)

It's not an incorrect spelling, just a British one. See Artefact. AntiDionysius (talk) 23:25, 7 November 2024 (UTC)