Talk:Pluto

Dwarf Planet

Is it still classified as a dwarf planet? Wolf O'Donnel (talk) 00:47, 9 June 2021 (UTC)

Yes, and everything within that term that the IAU insists. Best get used to it. I don't foresee it changing at any point in the foreseeable future, but this isn't a forum; this page is to talk about the article itself. 134340Goat (talk) 01:10, 9 June 2021 (UTC)

even though California legislation bill HR 36 [1] declared that Downgrading Pluto's status would "cause psychological harm to some Californians" and had "tremendous impact on the people of California" --- poor Californians! -- Wassermaus (talk) 10:30, 10 August 2021 (UTC)

From the text: The downgrading of Pluto reduces the number of planets available for legislative leaders to hide redistricting legislation and other inconvenient political reform measures...

Not to be taken too seriously, obviously. Dhtwiki (talk) 22:20, 10 August 2021 (UTC)

The term "Planet", including "Dwarf Planet" is now deprecated. The media did not use either term when describing the New Horizons flyby. "Planet" is no longer a useful term for scientific discussion, as it just creates more heat than light. Algr (talk) 14:39, 29 August 2021 (UTC)

If we're becoming a forum, let me say good luck with that line of reasoning. Imagine if geologists one day decided that the word "mountain" was defunct because there was no way to separate it from "hill". See how far that travels. Serendi^podous 14:46, 29 August 2021 (UTC)

Geologists did a much better job of defining their terms, and hence avoided the problem. Algr (talk) 03:44, 30 August 2021 (UTC)

No they didn't. They just set an arbitrary height line. If that's what you think we should have done with planets, fair enough. But I prefer definitions that, you know, define. Serendi^podous 08:40, 30 August 2021 (UTC)

I see little evidence that the terms planet and dwarf planet have fallen out of use. Plenty of media sources still use the terms,[2][3][4] And yes, even with New Horizons they identifies Pluto as a dwarf planet, albeit while still mentioning the "controversy" further down.[5] Like many, I was a bit angry about the change in designation when it happened, but that was 15 years ago now, and the newly defined distinction between planet and dwarf is clearly logical and rigorous, which the old system was not. You can't justify including Pluto as a planet but not Eris. And yes, the planet definition is clearly more objective than the mountain definition so it's a point for the astronomers there. Cheers  — Amakuru (talk) 08:50, 30 August 2021 (UTC)

There is nothing logical or rigorous about "Clearing the Neighborhood". It is an irrelevant over-complicated concept that has no scientific use beyond the objective of demoting Pluto. No one can explain how big Pluto's neighborhood is or why that size is relevant to anything. Is TRAPPIST-1 c in TRAPPIST-1b's neighborhood? The definition of "mountain" does not involve stuff on the other side of the Earth, and worked fine when used for objects on Mars. It would be much more clear an honest to say "Anything as large or larger than some arbitrary mass is a planet, unless it is big enough to trigger fusion by gravity." That at least communicates honest and useful information about the object. Algr (talk) 12:07, 30 August 2021 (UTC)

Let me know when Earth's Moon is defined as a true planet and then maybe I will care about Pluto. -- Kheider (talk) 15:18, 30 August 2021 (UTC)

A number of planetary scientists would say it already is, so, I suppose there's your answer. Shrug 134340Goat (talk) 17:45, 30 August 2021 (UTC)

Charon, hydrostatic equilibrium, barycenter

"First identified in 1978 by astronomer James Christy, Charon is the only moon of Pluto that may be in hydrostatic equilibrium; Charon's mass is sufficient to cause the barycenter of the Pluto–Charon system to be outside Pluto." Does the fact that Charon may be in hydrostatic equilibrium have anything to do with its mass being sufficient to affect the barycenter? If so, this sentence has 2 parts and could stand. If not, it has three parts and should be rewritten. --142.163.195.229 (talk) 00:25, 21 June 2021 (UTC)

Replaced the semicolon with a full stop. Double sharp (talk) 13:25, 15 September 2021 (UTC)

Relationship with Neptune

the section starting "If Pluto's period is slightly shorter than 3/2 of Neptune" ending with "The whole process takes about 20,000 years to complete" - is this something that really happens? If so, leave out the word "if". If not, change 'is' to 'were' and make the whole thing hypothetical.--142.163.195.229 (talk) 00:48, 21 June 2021 (UTC)

Yes, it happens. Changed to "When". Double sharp (talk) 13:16, 29 June 2021 (UTC)

'Resolvable disc'

What's a "resolvable disc" (only mentioned once). – Sca (talk) 13:31, 7 August 2021 (UTC)

If you look at a planet through a telescope, it resolves into a disc, like the Moon. If you look at a star through a telescope, it still looks like a star. Ditto if you look at an asteroid, which is why they're called asteroids. Pluto is so small that it didn't initially resolve a disc. In fact it was about the 2000s before we even saw Pluto's disc. Serendi^podous 17:24, 7 August 2021 (UTC)

I've changed the wording slightly, from "resolvable" to "viewable". Pluto was eventually "viewable" as a disc, so it was always "resolvable". Dhtwiki (talk) 22:09, 7 August 2021 (UTC)

Semi-protected edit request on 22 August 2021

Change Pluto from the dwarf planet classification to planet as it has been demonstrated the criteria used to claim Pluto is not only flawed, the body that voted to use it has violated their own criteria. 2603:7080:913F:60AF:1866:10D0:CE1A:D91D (talk) 23:26, 22 August 2021 (UTC)

 Not done: please provide reliable sources that support the change you want to be made. ScottishFinnishRadish (talk) 23:35, 22 August 2021 (UTC)

Regarding the infobox

Since I got reverted by Dhtwiki, let's discuss this:

I'm naturally aware that the common name is just "Pluto" without the MP number. However, that's also the case for every minor planet. For example, if you read 4 Vesta, you'll notice that it's always called "Vesta" outside the infobox header and the very start of the article. Why those two places – evidently because infoboxes often give the formal name even if that is not the article name. For some examples outside astronomy – see North Macedonia. Everywhere in the article it is called "North Macedonia", except one sentence in the lede where it is noted that its formal name is "Republic of North Macedonia", and the infobox heads off with that. Or China, where the same thing happens with its formal name "People's Republic of China". Or even United States, where the same thing happens with "United States of America".

(Also I feel that not having the minor planet number in the article title kind of goes against the almost-universal convention on WP where minor planets get the number regardless of whether or not they're the primary topic, e.g. 117 Lomia which Lomia redirects to, or 52246 Donaldjohanson when Donaldjohanson is a redlink. But since Pluto is by far the most famous minor planet, I can understand making it an exception.)

But at the very least, I think these precedents suggest that the minor planet number 134340 should at least be placed in the infobox, because that's where the formal name of an article subject usually goes. Double sharp (talk) 03:51, 28 September 2021 (UTC)

The minor planet number is a detail that doesn't need to be included in the main title for the Infobox. We had this debate regarding the name of the article itself about 15 years ago, but the key point is that "136199 Pluto" is not Pluto's official name, except in the minor planet catalogue. It is also not its common name, so it certainly doesn't belong in the Infobox title. The same should apply to other dwarf planets such as Eris, we shouldn't be confusing readers by including a number that's only relevant to a few specialists.  — Amakuru (talk) 06:39, 28 September 2021 (UTC)

Your logic makes sense, but my worry was that that's not how most other MP articles or comet articles do it. E.g. 2 Pallas uses the MP number in the article title and infobox header, and even Halley's Comet, which is titled by the common name, preserves "1P/Halley (Halley's Comet)" in the infobox header. But it's true that Pluto is by far more well-known than any of these, even Halley, which convinces me that leaving Pluto as an exception would not logically require us to change a lot of articles for consistency. So, I guess this is resolved for Pluto. As for the other less well-known dwarfs, I'll probably do a move request for them and see what happens.

P.S. Pluto is 134340; Eris is 136199. Double sharp (talk) 08:02, 28 September 2021 (UTC)

I recognize Pluto's MPC number when I see it, but if I have not thought about Pluto for months I can not recall the exact MPC number on demand. Before looking at List of minor planets: 1–1000, 19 Fortuna is the highest minor planet that I can recall the number to on any given day. I do know the numbers to 24 Themis, 52 Europa, 65 Cybele, etc, but I do not think of their numbers unless I am already thinking specifically of that asteroid. -- Kheider (talk) 08:53, 28 September 2021 (UTC)

It doesn't need a move request for Eris, Makemake etc, it's just an editing decision. We made the decision to move away from 136199 Eris in favour of Eris (dwarf planet) 15 years ago, so at least that part was settled. I might boldly try removing the number from the title of the infobox, having it consistent for all dwarf planets, and see what happens. (And yes, I got 134340 and 136199 mixed up, sorry... they really are awkward numbers!)  — Amakuru (talk) 09:30, 28 September 2021 (UTC)

Actually I had in mind a move request for the other dwarfs to the MP numbers for somewhat different reasons. But that's not particularly germane to Pluto (which is a different case because of how well-known it is), so I'll discuss that elsewhere when I actually write that. :) Double sharp (talk) 11:14, 28 September 2021 (UTC)

The Halley's Comet precedent is fairly convincing, but I can see Pluto being grandfathered in, since it's the only object for which the MPN was a modern afterthought. The other MP's are more problematic. 15 years ago there was a big deal about establishing DP's as a new category, and a lot of editors assumed that the IAU was going to play a role in this. But they haven't, and the issue is no longer so topical. The problem with removing the MPNs from DPs is deciding which bodies are MPs. Whose opinion do we use, since the IAU have (wisely) kept bureaucratic noses out of a scientific determination? Stern et al. count every object with a nominal diameter greater than Mimas. I know I couldn't keep track of them all, and because of measurement uncertainties, the cut-off is unstable. Grundy, Buie et al. count everything from Orcus on up (maybe now Salacia as well). If we're going by observationally established DPs, there's only Pluto and – maybe – Ceres (according to the only source I'm aware of, there are doubts about Ceres being in HE). Eris is generally assumed because it's more massive than Pluto, but that assumption was made when it was thought to be larger than Pluto as well. Instead it turns out to be denser, and denser bodies tend to have stronger 'rigid body forces'. I wouldn't be adverse to moving every TNO down to Orcus or maybe Salacia to '(dwarf planet)', except for Pluto, but I think it would be less OR-ish to move all but Pluto to MPN + name. — kwami (talk) 16:41, 28 September 2021 (UTC)