2851: Messier Objects

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Messier Objects
The debate over the correct Messier number for the Ship of Theseus is ongoing.
Title text: The debate over the correct Messier number for the Ship of Theseus is ongoing.


This comic is a play on the Messier Catalog, which is a famous list of astronomical objects "that are not a comet" compiled by the French astronomer Charles Messier in the 18th century. The real Messier Catalog includes 110 objects, which are all deep-space objects like nebulae and galaxies.

In the comic, it's humorously suggested that the catalog includes not just these distant celestial objects, but also very ordinary things found here on Earth. Each ordinary object is labeled with an "M" followed by a number, just as the real Messier objects are numbered (like M1, M31, etc.). However, the numbers are much higher than the 110 included in the actual catalog, and they point to mundane things such as the Earth, Charles Messier himself, a tree, a butterfly and a squirrel.

The numbers increase as the objects go from large and significant to humans (the Earth, Charles Messier) to those that are smaller and less significant (a tree, a butterfly, and a squirrel). However, this pattern isn't strictly numerical (i.e., there's no clear mathematical sequence), but rather a conceptual one where the numbers arbitrarily become larger for things that are commonly considered less monumental or noteworthy than celestial objects.

So, the comic is a playful take on a piece of astronomical history, suggesting that everything in the universe is part of the Messier Catalog, not just the deep sky objects Messier originally listed.

The title text refers to the Ship of Theseus. This is a popular thought experiment: if a ship is repaired and/or modified such that it has all of its parts replaced over the years, is it the same ship as the original? And then, what if you take all of the parts that were removed and create another ship using those parts? Are they both the same ship, and if not, which one is the original ship? The title text suggests that this leads to a debate as to whether the original ship and the new ship (with all of its parts replaced) should be considered the same object and therefore given the same Messier number, or the two ships should be considered different objects with different Messier numbers, and if so, which of them should retain the original number.

"M41592" may be a reference to pi as it contains 5 of the first digits at 3.141592. Also noteworthy is that (the real) M6 is called the Butterfly Cluster. However, there are no real galaxies in the original Messier Catalog named after trees or squirrels.[citation needed]

"M137" for Earth seems likely to be a reference to the animated sci-fi/comedy show Rick and Morty, since the versions of Rick and Morty primarily followed by the show come from Dimension C-137, even identifying themselves as Rick C-137 and Morty C-137 when around Ricks and Mortys from other dimensions.

About the Messier Catalog[edit]

The Messier Catalog was devised as a tool for comet hunters to differentiate between permanent, blurry celestial objects and the transient, moving comets that appear similar at first glance. Such blurry objects, unlike comets, remain fixed against the stellar backdrop, and their inclusion in the catalog ensures that astronomers could avoid mistaking these for newly visible comets, when systematically looking for unfixed 'fuzzy' objects to start to track. The catalog excludes terrestrial objects, as they pose no risk of confusion with comets.[citation needed] Following the creation of the Messier Catalog, other catalogs like the New General Catalogue (NGC) and the Sloan Digital Sky Survey (SDSS) emerged, expanding the documentation of astronomical bodies.

Similar Numbering Systems[edit]

This numbering system is somewhat reminiscent of Wikidata which also gives objects a number starting with a letter. Numbers starting with Q refer to concepts including specific physical objects (like the Earth) and more abstract ideas (butterflies as organisms known by a particular common name). Here are some of the objects mentioned in the comic:

Q2 (Earth) (The normal one)
Q14524 (Charles Messier) (The astronomer)
Q10884 (tree) (The plants known by that common name)
Q11946202 (butterflies) (The Lepidoptera known by that common name)
Q9482 (squirrel) (The taxon of rodents)
Q14530 (Messier object) (The astronomical catalog)
Q1050837 (Ship of Theseus) (The thought experiment)
Q13915 (xkcd) (The webcomic)


Ambox notice.png This transcript is incomplete. Please help editing it! Thanks.
[Multiple objects are labelled with M followed by a number.]
[There is a tree, a butterfly, a squirrel, a man with a powdered wig labeled Charles Messier, a squirrel, and ground.]
M137 (Earth) (pointing to the ground)
M205 (Charles Messier) (pointing to Charles Messier)
M21860 (pointing to a tree on the left of the panel)
M41592 (pointing to a butterfly above Charles)
M30712050 (pointing to a squirrel)
[Caption below the panel:]
People usually focus on the first 110, but the Messier Catalog actually includes all objects.

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addededededded transcript Me[citation needed] 17:34, 6 November 2023 (UTC)

meow someone, i guess(talk i guess|le edit list) 17:54, 6 November 2023 (UTC)

Is M30712050 that specific squirrel, or just the general category of squirrels? 17:57, 6 November 2023 (UTC)

The debate about the Ship of Theseus suggests that every ship gets its own number, so why not every squirrel? Although then the numbers would be much larger. Barmar (talk) 18:04, 6 November 2023 (UTC)
...and the list would be much messier. Yorkshire Pudding (talk) 18:32, 6 November 2023 (UTC)
It can't be all squirrels, CM could not have seen *all* squirrels. In fact, he would have been dead long before *that* squirrel was born. SDSpivey (talk) 21:20, 6 November 2023 (UTC)
Presuming that Messier is alive in this panel, then this panel isn't the present, and the squirrel was alive when Messier was alive. 21:58, 6 November 2023 (UTC)

could the numbers have been picked to represent something rather than be entirely random? like 41592 coming from pi and 137 being FSC... idk maybe i'm just reading too much into it... 18:09, 6 November 2023 (UTC)

i mean...every finite string of numbers "comes from" pi Me[citation needed] 15:42, 9 November 2023 (UTC)

Between the Messier catalog and the Marvel multiverse, we've got a well-defined numbering system that indexes all objects in all universes. (Or, I guess at least those universes with Messier catalogs. Damn.) 19:03, 6 November 2023 (UTC)

You should also number all Messier catalogues (and intermediate versions of them), then, to make sure we know which ones we're talking about. 00:47, 7 November 2023 (UTC)
Furthermore, each entry in the catalog should have it's own entry in the catalog. 02:57, 8 November 2023 (UTC)

Wait a minute... this is just the wikidata QID system againataraxianAscendant (talk) 19:34, 6 November 2023 (UTC)

Yes, it's like Wikidata. Not sure if it's worth mentioning. Unfortunately, the numbers don't match those Wikidata for equivalent objects.
Furtermore, Wikimedia Commons ID use an M and a number. For example, https://commons.wikimedia.org/entity/M205.--Pere prlpz (talk) 19:39, 6 November 2023 (UTC)
Wikidata does something similar, but they use /Q\d+/ instead. Me[citation needed] 15:45, 9 November 2023 (UTC)
I added a section about Wikidata because the first thing that I wanted to do when I read this comic was look up what the IDs were for all of the objects mentioned. It certainly could be written better. Brycemw (talk) 15:31, 7 November 2023 (UTC)
Ha! Edit conflicted. Sample of diff (-my submission and +the one that got there just before me):
   :Q1050837 (Ship of Theseus) (The concept, only...)
   :Q1050837 (Ship of Theseus) (The thought experiment)
Oopsies! the one on the bottom is mine haha. someone, i guess(talk i guess|le edit list) 18:45, 7 November 2023 (UTC)
Great minds think alike! (Fools never differ...) 16:19, 7 November 2023 (UTC)

The existence of a Messier catalog implies the existence of a Neater catalog. 19:42, 6 November 2023 (UTC)

The explanation suggests that we might number every grain of sand. But the comic just has a single number for "Earth". Would the catalog have separate entries for an object and all its constituents? It doesn't seem like it, since Randall didn't label the wings of the butterfly, limbs of the squirrel or human, or branches and leaves of the tree. Of course, how we distinguish distinct objects in the world is an even thornier philosophical problem than the Ship of Theseus. Barmar (talk) 20:36, 6 November 2023 (UTC)

I deleted that portion as non-explanatory wild speculation. 21:03, 6 November 2023 (UTC)
The same would apply to the real Messier Objects too - do you label a star cluster, and then label the individual stars within it as well? 10:04, 7 November 2023 (UTC)

Shouldn't Earth (or Messier) be object #0? SDSpivey (talk) 21:20, 6 November 2023 (UTC)

You'll need to bring that up with Messier... 15:52, 8 November 2023 (UTC)

How messy are they? đŸ„ 22:00, 6 November 2023 (UTC)

Earth number might be influenced by Dimension C-137 from Rick and Morty, which often is used to refer to the "Earth" location from early easons. -- 22:27, 6 November 2023 (UTC) (edit 22:33, 6 November 2023 (UTC))

For the numbering of the ships of Theseuses, why not just use the numbers from a particular type of prime number? ----

In the UK, the Ship of Theseus problem is sometimes referred to as Trigger's Broom, after a character from one of our most popular sitcoms ("Only Fools And Horses"). Trigger is a mentally-deficient road sweeper who is proud of the fact that he's still got his original broom that he was given when he started work 20 years ago. He's looked after it in that time: it's had 17 new heads and 14 new handles... 06:21, 7 November 2023 (UTC)

To be fair (and, unfortunately, historically unfair to the Irish), that's just a transplant of the older "Irishman's Broom". And it's just one of many variations like "grandfather's axe", etc. Depends on whether you're going for fairly recent pop-culture (lovely-jubbley!), falling back on old stereotypes (to be sure, to be sure) or whatever else you have in mind. (I'm sure I actually heard "Ship of Theseus" said on the street, just the other day, by a conversing couple. And this wasn't even an Oxbridge street!)
To be fair to Trigger, the council for whom the character worked was also as blind/far-sighted regarding the philosophical (dis)continuity of existence, given the award in which they were citing the broom as one of the outstanding features... Much as the US Government treats the 'modern' USS Constitution as the same as the 'original', maybe? 09:02, 7 November 2023 (UTC)

Could the M137 for earth be a Rick and Morty reference, since that is their earth/universe-number as well? Eugen (talk) 09:54, 8 November 2023 (UTC)

We gotta go to xkcd, Morty! There's no time to explain, get in, Morty! someone, i guess(talk i guess|le edit list)
I think it's close to impossible that this ISN'T a Rick And Morty reference, well spotted! That should probably go in the explanation somewhere... NiceGuy1 (talk) 05:04, 11 November 2023 (UTC)

Another interpretation isn't so much that the higher-numbered objects are less "significant", but more that Messier numbered them in order, and so higher numbers mean objects that Messier took longer to get around to numbering. It took him until object 206 to think to number himself, and other things such as random specific squirrels have much higher numbers because he didn't get to them until much later in his cataloguing process. 16:13, 9 November 2023 (UTC)

Concerning trees and squirrels, this assertion can and indeed should be supported with a citation (citing any adequate souce listing the objects in the catalogue). I have therefore changed the "fact" tag to "Actual citation needed" to avoid confusion with the humourous version. Whether the assertion is correct or not is questionable. One could argue that M5, the Rose Cluster, is named after the rose tree; that M20, the Trifid Nebula is actually the Triffid Nebula; and that M93, the Critter Cluster, refers to a variety of critters, including squirrels.Catherine (talk) 00:53, 11 November 2023 (UTC)

Okay, so right now where it says there are no Messier-numbered galaxies named after trees or squirrels, it says "Actual Citation Needed". I would assume the only proof of this would be to cite the actual list to note no squirrels or trees in it (squirrels obviously, I feel like trees would be plausible). So, how do we do an actual citation? Link to the list somewhere reliable and put a footnote like on Wikipedia?

Also, I feel like there's an intentional joke that the first object available to Messier, himself, is numbered as low as 205. Like logically he'd be 1 (or 0, if he wanted to keep actual numbers for actual celestial bodies) or 111. NiceGuy1 (talk) 05:04, 11 November 2023 (UTC)

Numbered in the order of being first observed, from the moment he set his mind to it? And there were no mirrors (that weren't probably concave and mounted in his telescope*) in direct view for the first couple of hundred observations? His notepad given zero, perhaps? What of his pen(cil)? The non-telescopic mirror would have been 205, perhaps, or lower, depending on how he came upon it.
* Hmmm... Whereupon is numbered the telescope he initially used? Unless using some special "need a full, all-round, unoccluded view" rule as part of his internal process of concluding a valid observation.
Fleeting sideling glimpses (and being, ironically, far too close) could defer many, many things from snap consideration. It does suggest The Earth should be almost the last thing to be numbered (after "the inside of the Apollo 8 capsule"?), but perhaps his particular systematic rationale has occasionally been revised... 11:32, 11 November 2023 (UTC)
Even without mirrors, there's still reflections in water (I feel like there's other natural mirrors, but I can't think of any). Also, you only need a reflective surface to see your own face - and more than that to see your back - but people generally can see all of their front from the chest down (chest, stomach, arms, legs, hands, feet...)... Even some of our backs (butts, back of the legs and arms) by moving our parts around. Messier is still the first observable object to Messier. :) NiceGuy1 (talk) 06:06, 19 November 2023 (UTC)
"Messier object 0: Messier's nose". Beyond that (and I think that the flash of inspiration is as likely, or more, to have struck when his dominant eye is firmly stuck to an eyepiece, rendering even his nose not directly visible), you have to at least be paying attention to notice even your own hands in front of your face. If you first action is to contort yourself to assess exactly how steatopygian your gluteals are, then you're probably thinking of far different things than astronomy, or even just "what can I actually see, in front of me?" (apart from that pencil and paper, presumably). The mysterious backstory behind the (in-universe) sources of the comic's details are, of course, unknown, but you can probably defer some assumptions as less likely than others. 17:03, 19 November 2023 (UTC)