Talk:Halley's Comet

Western vs Oriental

The article refers to the last year for which "oriental records were better than western" records. Shouldn't one compare oriental to occidental, or eastern to western records? This reads as grammatically confused. 216.163.246.3 (talk) 21:55, 17 October 2023 (UTC)

Point taken. Serendi^podous 23:57, 17 October 2023 (UTC)

Does halley's comet exist in 2024?

If , so then you can surely edit this Wikipedia article for Halley's comet existing in 2024? 121.74.164.184 (talk) 04:43, 28 January 2024 (UTC)

ref label b?

In "Structure and composition" is "^[b]" which seems to do nothing. Anyone know what this is for or how to fix it? Al Begamut (talk) 22:47, 6 April 2024 (UTC)

@Al Begamut: This has been the case since the article was vandalized on 8 March 2010, 14 years ago.[1] The edit was partially, but not completely, reverted 12 minutes later,[2] by what may well have been the same editor who originally vandalized it (both were made by unregistered IPs). The page syntax has been broken ever since. It should work again now.[3]

I have never seen a Featured Article that had such blatant vandalism stand for so long. Renerpho (talk) 06:35, 29 June 2024 (UTC)

I appreciate very much your detailed explanation; as an editor with limited range of experience, this insight is helpful to me. Al Begamut (talk) 13:12, 29 June 2024 (UTC)

@Al Begamut: This is now listed at Wikipedia:Wikipedia records#Vandalism, as the longest undetected vandalism on a featured article. Thanks again for bringing it to our attention! Renerpho (talk) 19:08, 29 June 2024 (UTC)

Wow, all right then. Pleased to have helped! Al Begamut (talk) 12:50, 1 July 2024 (UTC)

684 CE depiction?

The table of apparitions claims that the comet is depicted in the Nuremberg Chronicle, which for some time was thought to be the oldest depiction of a comet. This claim, which was popular since the 1960s, has been disproven in 1989. I don't know why it is in this Featured Article, and with a source from 1985! Renerpho (talk) 06:00, 29 June 2024 (UTC) Renerpho (talk) 06:00, 29 June 2024 (UTC)

I removed both mentions of it. Renerpho (talk) 19:09, 29 June 2024 (UTC)

References

Considering nomination for FAR

I am considering nominating this article for Featured Article Review. Looking at the article talk page, it is apparent that nobody is taking care of the maintenance of this level-4 vital article. There has been a case of blatant vandalism that was introduced two months after the article was promoted to FA status, in March 2010, which broke the page syntax. The issue was raised on the talk page three months ago, with no replies. I just corrected it now, after it stood in the article for 14 years.[4]

This was just after I had tagged a claim about a historical observation of the comet as dubious (what to do about it remains to be discussed, see Talk:Halley's Comet#684 CE depiction?). That particular claim was popular since the 1960s, but was disproven in 1989. It stands in the article twice -- first with a source from 1985, and then a second time without a source. It was first introduced in January 2009,[5] and has remained completely unreferenced for a long time (only to be eventually referenced with an outdated source, rather than be removed). While not as outrageous as the vandalism, it suggests to me that this article has not been thoroughly reviewed in December 2009, or when it became a FA in 2010.

I didn't look very hard... What else is there that to be found that could disqualify this article from FA status? Renerpho (talk) 07:03, 29 June 2024 (UTC)

If you are going to take this to FAR, I expect you to be here for the long haul. Your FAR of Sedna was a farce. You disappeared after 4 days and left me to carry the load for a clueless review team for eight solid months. And the article wasn't ultimately changed much at all. I fully expect this FAR to go exactly the same way. I hope you're willing to prove me wrong. Serendi^podous 13:08, 29 June 2024 (UTC)

@Serendipodous: Following that last FAR, I said I'd probably not nominate anything for FAR again. I've been discussing this question off-wiki today, and I decided I won't nominate Halley's Comet, because that's an experience I don't want to repeat (for myself, and others).

That doesn't mean that there aren't problems with the references for this article, beyond what I said before: Renerpho (talk) 20:34, 29 June 2024 (UTC)

•  Fixed Ref.29 repeats the outrageous claim that Halley's comet was depicted in the 7th century, and it may actually be the original 1967 source for that idea. Galaxy Science Fiction is not a scientific publication, and has no place in this article.
•  Fixed Ref.59 (a 2010 BBC News story) is based on an article in Journal of Cosmology,[6] which is not peer-reviewed, and is generally regarded as WP:FRINGE. BBC News may generally be reliable, but it's not useful for science news.
•  Pending Ref.144 are incomplete. This is just a claim that would need a [citation needed] tag if it appeared anywhere else in the article.

  This is now ref.137. Renerpho (talk) 02:16, 1 July 2024 (UTC)

•  Fixed Ref.101 is self-published, and the author is an expert in folklore, Fortean phenomena, and ufology, which doesn't make him more reliable for a claim about the history of astronomy. Surely there are better sources for the earliest photograph of the Moon than this? Renerpho (talk) 19:05, 29 June 2024 (UTC)
•  Fixed Ref.126 appears to be a duplicate of Ref.125 (or a reprint of the same article in a different newspaper). Ref.126 leads to a dead URL, so I cannot check.
•  Fixed Ref.127 is another reference to Galaxy Science Fiction. The information may be true, but since this is not a peer-reviewed source and the author appears to be a sci-fi author, not a scientist, it's probably not suitable as a source.
•  Pending Ref.145 is incomplete as well. This is most likely S. Milbrath's Star Gods of the Maya, which isn't in the bibliography. And a page number would be nice... Renerpho (talk) 20:19, 29 June 2024 (UTC)

  This is now ref.138. It still needs a page number. Renerpho (talk) 02:17, 1 July 2024 (UTC)

•  Fixed Ref.82 looks questionable to me. I am not sure if that source exists, or at least where to find it. A Google search for the title[7] gives two results: This Wikipedia article, and a deleted Reddit post. The Wikipedia article about the author, Lupus Protospatharius, doesn't list a work of that name. Renerpho (talk) 20:34, 29 June 2024 (UTC) Found it; the title given here was wrong. I'll replace the ref. Renerpho (talk) 20:46, 29 June 2024 (UTC)
•  Fixed I have replaced ref.105 by a more reliable source. Renerpho (talk) 21:00, 29 June 2024 (UTC)
•  Fixed Ref.106 came with very little information. I have expanded it as far as I can (and added a link to its Google Books page), but there is no page number, and I cannot find the thing that this is supposed to say in the book. This looks like a "failed verification" to me. Renerpho (talk) 21:09, 29 June 2024 (UTC)
•  Fixed Ref.107 just gives a link to an online library, which appears to be dead. The citation doesn't say anything about the actual source, just that it appears in the digital library of Paris Observatory; so digging up the original reference may be tricky. The URL has actually been archived,[8] but it includes nothing of interest, so this is another "failed verification". Renerpho (talk) 21:15, 29 June 2024 (UTC)

I'm not sure what you're asking me to do to ref 144 (now ref 140). The link in ref 107 works fine for me; the fact it states is corroborated. I'm just not sure how to cite it. Serendi^podous 21:21, 29 June 2024 (UTC)

@Serendipodous: The ref.144 I mentioned is now ref.137 ("The poets Kurunkozhiyur Kizhaar and Koodaloor Kizhaar..."). If the link in ref.107 works for you then that's great. What does it lead to? Renerpho (talk) 21:30, 29 June 2024 (UTC)

Yanaikatchai Mantaran Cheral Irumporai does cite it, but I don't understand the citation format used in that article. Renerpho (talk) 21:33, 29 June 2024 (UTC)

Ref 107 is just a picture of an ad featuring Halley's comet, which is all the text says. Serendi^podous 21:35, 29 June 2024 (UTC)

Thanks. The Sangam literature of Ancient Tamils needed for ref.137 isn't known to Google Books. Any other idea where to find it? Renerpho (talk) 21:38, 29 June 2024 (UTC)

I don't think it's a book; I think the cite is directly quoting the Sangam literature of ancient Tamils. Serendi^podous 21:41, 29 June 2024 (UTC)

Okay. Maybe the citation makes sense to someone who knows about that field, but to me, it is quite vague. Maybe Purananuru leads to the actual location? Renerpho (talk) 21:44, 29 June 2024 (UTC)

I think [9] includes the quote needed. A Google Books search for an excerpt of the quote gives that book as the only result.[10] Sadly the search inside the book doesn't work. Renerpho (talk) 21:48, 29 June 2024 (UTC)

The link in ref 107 works fine for me; the fact it states is corroborated. I'm just not sure how to cite it. I redid the citation, per the format that's suggested on the source page (which is now working for me). Renerpho (talk) 22:28, 29 June 2024 (UTC)

•  Fixed @Serendipodous: In this edit, you've removed the statement that Flammarion was misquoted, which had been tagged as needing a citation. The source[11] only says that the press reported him saying this. I don't think we can be sure that he actually did, or believed it. Or do you have another source, beyond "as far as I can tell, he did say this"? Renerpho (talk) 21:56, 29 June 2024 (UTC)

  See Camille_Flammarion#Halley's_Comet for Flammarion's actual statements about this. He didn't believe it, and was quite annoyed that the press reported that he did. Quote: "When astronomers announced that the Earth would pass through the tail of Halley's Comet in May 1910, Flammarion was widely reported, in numerous American newspapers, as believing that toxic gases in the tail might "snuff out all life on the planet". In fact, he said no such thing." Renerpho (talk) 22:06, 29 June 2024 (UTC)

•  Pending I added the book by Goodrich, which already existed as a reference. The exact place in the source is on pages 64 and 83. I can't get it to display ^[103]p.64,83 or something of that sort. Renerpho (talk) 22:17, 29 June 2024 (UTC)
•  Fixed There are a number of citations in the lede section that don't look controversial to me. The reference for the orbital period doesn't seem necessary, and the reference that the comet was named after Halley doesn't actually do much (it leads to an article published by Halley himself -- so what?). Surely we don't need a primary source for this claim anyway? Do you think we can get rid of those, and the others? Renerpho (talk) 22:35, 29 June 2024 (UTC)
•  Fixed Ref.65 is a link to a Wikipedia article (Yanaikatchai Mantaran Cheral Irumporai) that is itself tagged as "needs additional citations for verification". That's doubly bad. Renerpho (talk) 19:07, 30 June 2024 (UTC)

  Compare the problem with what is now ref.137. Renerpho (talk) 02:16, 1 July 2024 (UTC)

•  Pending There is now a ^[who?] tag in the 1145–1378 section. The source we have (a New York Times article) is insufficient. Renerpho (talk) 21:15, 30 June 2024 (UTC)

  Similarly to the BBC news article we had, the 1997 New York Times article is a case where something is claimed in a newspaper article, without indicating a source.

  The first mention of this that I can find is from 1985, D. J. Arneson's "Halley's Comet. A brief guide to comets"[12] whose author is neither a historian nor an astronomer. It spends a single sentence on Khan and the 1222 apparition.

  This is repeated with a little more detail in the 1986 Third World International, which mentions it in passing (this magazine is neither about astronomy, nor about history). It says that "Genghiz Khan is said to have halted his invasions of Eastern Asia on sighting Halley's comet in 1222 and change his course to unleash his fury on the Muslim world instead". This may be so (or not?), but who said it, and where?

  All the online sources about this are non-specific. There are mentions on the Science Museum website and on history.com, but both may relate back to our Wikipedia article. What we need is a scientific article from 1985 or earlier that references the primary source. Renerpho (talk) 21:36, 30 June 2024 (UTC)

Cosmic Wonder: Halley's Comet and humankind appears to cite the original source but I'd have to buy it to find out. Serendi^podous 14:11, 1 July 2024 (UTC)

•  Pending In the introduction to the apparitions table, it says: Perihelion dates of 1531 and earlier are in the Julian calendar, while perihelion dates 1607 and after are in the Gregorian calendar, with [13] as the source. I was uncertain if that was how we should do it, considering that most of Europe only switched to the Gregorian calendar around 1700. In particular, Halley himself would have used Julian dates exclusively.[14] So I checked how our source(s) do it, and there's a problem: Our table gives 27 October as the date of the 1607 perihelion, while the source gives it as "1607 October 26.80", but clearly says that this is the Julian date. One of the two is wrong. I'd usually say that we're wrong and the table is right. Small discrepancies (of order <1 day) aside, the problem is that JPL's Small Body Database gives the date of the 1607 perihelion as JD 2308304.0406, 1607-Oct-27.5406 (see select orbit, 1607-Oct-24), and those are only the same date if the latter is meant to be Gregorian.[15] JPL admits on their page that the epoch for the 1607 orbit may be ambiguous, and that they do not know what the correct epoch in their source is meant to be, so whether they can be trusted as a source for the date is unclear. Still, we have two reliable sources that contradict each other, and our article contradicts the source we're citing. Renerpho (talk) 23:04, 30 June 2024 (UTC)

  By the way, the source we're citing also gives a Julian day for the 1607 perihelion (2308303.79922), which is inconsistent. The Minor Planet Center, which is the 2nd source we're citing for the date, take theirs from JPL, but as I said, JPL themselves don't seem to trust it... Renerpho (talk) 23:07, 30 June 2024 (UTC)

•  Pending I have replaced one instance of the Keller (2005) reference with the original paper by Hughes (1985). Keller mentions Hughes' result in passing, but his version of it isn't quite what the original source said.[16] It may be worth checking all references for whether they are the original source, or are just citing someone else's work. The original is usually preferable, due to instances of Chinese whispers like this. Renerpho (talk) 00:34, 1 July 2024 (UTC)

  I have started doing so, beginning with the references to JPL (see below). Renerpho (talk) 02:11, 1 July 2024 (UTC)

•  Fixed I have added an archived URL to the dead ref. 8 ("What Have We Learned About Halley's Comet?"), but I am not convinced that this is a reliable source for the kind of information it is used for in our article. It's not peer-reviewed, doesn't cite sources, and the authorship is unclear. Luckily, it looks like we're not using it for anything wild, so it should be possible to replace it. I'll start working on that right way. Renerpho (talk) 00:45, 1 July 2024 (UTC)

  Replaced with Reitsema, Keller1987 and Altwegg1993. The size of the coma given in the old reference disagrees with the size given in Altwegg1993, by a factor of about 5. Altwegg1993 actually shows the measurements done by the Giotto spacecraft, and appears much more reliable. Renerpho (talk) 01:31, 1 July 2024 (UTC)

•  Fixed Note b ("Jet Propulsion Laboratory lists its average diameter as only 11 km") is an editorial statement that may be undue. JPL doesn't say "average diameter", but most likely refer to its mean diameter (and that's how we use it in the infobox, too). Using the formula from mean diameter, the dimensions given before would result in a diameter of $(15\cdot 8\cdot 8)^{1/3}=9.9$ km, so the word "only" is not justified. I've rephrased it. Renerpho (talk) 00:55, 1 July 2024 (UTC)

  I have now moved the note into the main text, and have completely removed JPL as a source for the size. The primary source, as used by JPL, is Lamy (2004), who specify that they're talking about mean radius (diameter) on p.230, and who explain in more detail how they got from the three axes (per the snapshots taken by Giotto and the Vega spacecraft) to an effective size. The numbers, previously looking inconsistent (11 vs. 9.9), make sense with their adjustments. Renerpho (talk) 02:07, 1 July 2024 (UTC)

•  Pending In the Structure and composition section, we are using two different sources for the comet's mass (M=2.2 × 10¹⁴ kg) and density (d=0.6 g/cm³). That's fine in principle, but the two are inconsistent with each other. They'd result in a volume of M/d=367 km³, or an effective radius of 4.4 km,[17] 20% too low. Can't we find a source that gives both mass and density, in a way that is more consistent with what we know about the comet's size? Renerpho (talk) 02:31, 1 July 2024 (UTC)

  Note that the density we give in the main text doesn't reflect what we say in the infobox, where we give a wide range of possible densities (0.2–1.5 g/cm³). With that, the problem of inconsistent mass/density goes away, as long as we don't rely on the value of 0.6 g/cm³ too much. Renerpho (talk) 02:33, 1 July 2024 (UTC)

  Reading ref. 17, on p.213, near the end of the right column it gives consistent mass, density and size estimates, together with sources for each. Maybe we should just switch to that. Renerpho (talk) 02:58, 1 July 2024 (UTC)

  The numbers given in ref. 17 are: M=1–3 × 10¹⁴ kg, V=365 km³, d=550±250 kg/m³. These also give a better indication of the uncertainties involved. The source given in ref. 17 for the mass is Rickmann H. (1989), Adv. Space Res., 9(3), 59–71, where the name is an apparent misspelling of Hans Rickman. His article is not only younger than our source (Cevolani, 1987), but also doesn't claim more than the data supports. The original numbers from Rickman are: M=1.3–3.1 × 10¹⁴ kg, d=0.28–0.65 g/cm³ (that density is based on an unspecified size estimate, so the density in ref. 17 is more reliable).

  Are there any objections against replacing ref. 9 and 10 by "ref. 17 plus Rickman"? Renerpho (talk) 03:14, 1 July 2024 (UTC)

Go ahead. Serendi^podous 13:48, 1 July 2024 (UTC)

•  Pending The article states that Changes in the flow of the solar wind can cause disconnection events, in which the tail completely breaks off from the nucleus, where the wiki-link leads to Comet. That article says nothing more about what a disconnection event is than we're doing here. I don't know if the wiki-link should be replaced entirely, removed, or if we just need to do a better job explaining what it means. Note that disconnection event as a redirect is different from what we are doing. Renerpho (talk) 02:44, 1 July 2024 (UTC)
•  Pending Quote from the article: Although only 25% of Halley's surface was imaged in detail during the flyby missions, the images revealed an extremely varied topography, with hills, mountains, ridges, depressions, and at least one crater. The reference at the end of that statement, ref. 17 supports the second half of it, but there's nothing about the proportion of the surface that was imaged, and the number 25% appears nowhere in that article. We need an additional source after "during the flyby missions". Renerpho (talk) 02:58, 1 July 2024 (UTC)

Images

Is it just me, or does the article look cluttered? There are a lot of images, and many look either unnecessary, or not well-placed. Renerpho (talk) 22:12, 29 June 2024 (UTC)

Yes there is some image clutter in the History section. I'm not sure that some of those images add a lot of value. Praemonitus (talk) 18:42, 30 June 2024 (UTC)

@Praemonitus: I've reworked the image placement and selection. What do you think? Renerpho (talk) 21:00, 30 June 2024 (UTC)

@Renerpho: Okay I guess. The {{Multiple image}} template could be used for combining multiple images vertically. Praemonitus (talk) 03:39, 1 July 2024 (UTC)

@Praemonitus: Good idea, thank you! I've done a bit of an editing marathon (70 edits and lots of reading over the last 8 hours), and I'm about to sign off. There were quite a few issues that I've been able to fix. I have started to go through the references one by one. Having looked at about a third of them already, there are some issues where a solution isn't straightforward, or where I'm not sure what to do; those are now marked as  Pending (or as  Fixed if they've since been solved). I have summarized some of the journal articles I've read that are not yet used as references, but which may become helpful. I'll see if I can pick up tomorrow from where ever the article stands then. Renerpho (talk) 03:46, 1 July 2024 (UTC)

Shortened footnote template

The article is citing sources in the bibliography, but is doing so inconsistently. I'd like to convert those to use the {{sfn}} template. Does anybody object? Praemonitus (talk) 18:39, 30 June 2024 (UTC)

I don't object. There are a number of sources that can be moved from the references to the bibliography section. Goodrich is one example (maybe that gets rid of the problem I mentioned above, 22:17, 29 June 2024). Milbrath's book is also better handled that way, and maybe a few others that I'm missing. Renerpho (talk) 18:57, 30 June 2024 (UTC)