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)

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.

Media addition suggestion

Do you guys think a simulation like this would add value to the page ?

This particular Gif was made with a render engine me and a friend made. Obviously for a included version i would make a 1080p version.

My argument for why this adds value; We have a lot of very good technical illustrations of say geodesics but at least in my opinion there is still a general confusion regarding how the image of the disk changes depending on the view direction. All renders tend to just show the disk perpendicular to the viewing plane. I think adding a simulation like this could be a good way of illustrating how the image actually changes a lot. This particular simulation includes the Kerr Metric, Time Dilation, relativistic beaming, relativistic doppler effect and a physically accurate blackbody model. So the colors of the disk are accurate, in so far as if we pretend the disk is like 2000 Kelvin hot. For a showcase we could switch the temperature distribution model to something more accurate. Erik Hall (talk) 21:52, 5 August 2023 (UTC)

That file doesn't appear to be freely licensed, so it can't be added regardless. Di (they-them) (talk) 01:06, 29 August 2023 (UTC)

Isn't the creator of the image the one making the suggestion? ——Digital Jedi Master (talk) 15:59, 12 October 2023 (UTC)

Clearer Image Found

The photo used is actually from an unfocused lens from the Perseverance Rover on Mars. The "black hole" is actually the "moon" Phobos orbiting Mars and eclipsing the sun.

https://www.youtube.com/watch?v=wwEoyntzAz0

I told you it was fake. 76.135.35.127 (talk) 17:01, 4 October 2023 (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)

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)