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?
13 comments