Plutoid
Self-referential taxonomy shock
June 26, 2008 13 comments
Apologies for my extended absence (or at least teleabsence). The blogging hiatus (or bliatus) will last a while longer, but I did want to punctuate it with what is to my mind the most fascinating linguistic-astronomical news of the month. You will remember the kerfuffle in 2006 over Pluto being stripped of its status as a planet. For a time there it was relegated to the description “dwarf planet”. ((Once you have decided to stop using “dwarf” to describe certain people, can you really use it much longer for anything else, except maybe for Snow White’s bearded harem? Well, apparently some female whales worms that munch on dead whales enjoy dwarf male harems too. But I notice that Apple does not offer an iPod Dwarf.)) But now it has been officially decided what Pluto really is.
It’s a plutoid.
A little circular, wouldn’t you say? It’s fine to call other lumps of rock Plutoids, if by that you mean “they’re a bit like Pluto”. (Asteroid actually means “like an aster” — ie, a star; “android” means “like a man”, and so forth.) But to say that Pluto itself is classified as being “something like Pluto” makes my head hurt.
Science explains, under the deadpan headline “‘Plutoid’ Chosen As Name For Solar System Objects Like Pluto”:
Plutoids are celestial bodies in orbit around the Sun at a distance greater than that of Neptune that have sufficient mass for their self-gravity to overcome rigid body forces so that they assume a hydrostatic equilibrium (near-spherical) shape, and that have not cleared the neighbourhood around their orbit. The two known and named plutoids are Pluto and Eris. It is expected that more plutoids will be named as science progresses and new discoveries are made.
The dwarf planet Ceres is not a plutoid as it is located in the asteroid belt between Mars and Jupiter. Current scientific knowledge lends credence to the belief that Ceres is the only object of its kind. Therefore, a separate category of Ceres-like dwarf planets will not be proposed at this time.
But if it ever is, they will be called ceresoids, right?
Of course, a lot of people think Wittgenstein was completely bonkers (not least in that sentence).
Pedant says: I think that it is the “bone-eating worms” munching on whale carcasses that have harems of tiny males living inside of them, not the late cetacean itself.
But we are all hominoids (apart from certain virtual phenomena such as ‘Melanie Phillips’, of course).
Lovely Wittgenstein reference. And thanks for the correction on whalebone-munchers.
Re hominoids: I think the appropriate analogy with “plutoid” would be if we called all human beings (not just “Melanie Phillips”) “androids”.
Is my crappy mp3 player an iPoid? Is the iPod “nano” an iPoid dwarf?
That sentence of Wittgenstein’s is great. To say that the standard metre in Paris was 1 meter long would have been “begging the question” in the correct sense.
Would Wittgenstein have accepted the news that the mass of the official kilogram is, er, no longer a kilogram?
Re: “androids”
Unacceptable sexism, Steven. What about us “gynoids”?
“These aren’t the ‘noids we’re looking for.”
[…] one of the most intelligent of all blogs, an article on the newly-coined astronomical term, “plutoid” But now it has been officially decided what Pluto really […]
Apart from its being self-referential, I’m wondering what the utility of the classification is. What is the important dividing line between Pluto and Eris on one hand and Sedna, Ceres and Quaoar on the other? Is it (as I suspect) motivated by sentiment? Are Pluto and Eris somehow peculiar objects that require a classification separate from Planets and Dwarf Planets?
…also, the specificity of the definition means that we cannot find Plutoids around other suns, right? We might find extra-Solar planets, or conceivably Dwarf Planets, with good enough telescopes, but not Plutoids.
…also, the specificity of the definition means that we cannot find Plutoids around other suns, right? We might find extra-Solar planets, or conceivably Dwarf Planets, with good enough telescopes, but not Plutoids.
Oh, I thought that was the whole point: that, much like “hominoid”, this is a classification named after the first (named) instance of its class.
If we’re not expecting to find a bunch of plutiods in other star systems, then yes, I agree that it’s a dumb word.
Also see this wherein a teenage journalist considers Kafka “Kafkaesque”.