Plutoids: a new class of objects beyond Neptune, Astronomy, politics or damage control |
Plutoids: a new class of objects beyond Neptune, Astronomy, politics or damage control |
Jun 12 2008, 09:44 AM
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#1
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Member Group: Members Posts: 340 Joined: 11-April 08 From: Sydney, Australia Member No.: 4093 |
Article on the BBC website: 'Non-planet' Pluto gets new class
http://news.bbc.co.uk/2/hi/science/nature/7449735.stm QUOTE Now an IAU committee, meeting in Oslo, has suggested that small, nearly spherical objects orbiting beyond Neptune should carry the "plutoid" tag. It also goes on to say that not everybody is too excited about it: QUOTE "It's just some people in a smoke-filled room who dreamed it up," he told the Associated Press. "Plutoids or haemorrhoids, whatever they call it. This is irrelevant." -------------------- |
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Jun 16 2008, 05:18 PM
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#2
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Member Group: Members Posts: 214 Joined: 30-December 05 Member No.: 628 |
I don't understand why this topic provokes so much emotion.
The more different space objects we identify and interact with, the more details we will want to take into account when we try to categorize them. And for the above mentioned continuum reasons, none of the categorizations will ever be a perfect fit. But this shouldn't matter to the people here on this site who are already well aware of the imperfections of whatever classification system is in force. When those imperfections become too constraining, the system will be modified again, but it is only ever going to be an heuristic convenience. It seems we are all up in arms about how OTHER people will be confused - children, politicians, the man and woman on the street. How will the imperfections of the labeling scheme warp their understanding of the underlying science? The incentive to learn more probably comes from the subject matter itself. Some of those other people will push on to learn more and others won't. This seems quite normal and not especially deplorable, since many of those who continue to rely on an oversimplified and somewhat inaccurate view of outer space will obtain a deeper understanding of some other area in which they become the experts who are best in touch with the underlying reality. I don't worry that interested children are going to be stopped in their tracks by Pluto's demotion. Disclaiming any serious knowledge of linguistics, I am still not too surprised that languages evolve. All the heated debate is entertaining and certainly not harmful, and the fact that some organized group of experts is trying to direct the process probably inspires a "Who do they think they are?" response, but ultimately the constructs that survive will be those we find convenient to use. And after a while they won't seem so convenient any more and something else will come along. "Plutoid" will do for now, but certainly not forever. |
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Jun 18 2008, 06:53 PM
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#3
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Senior Member Group: Members Posts: 2530 Joined: 20-April 05 Member No.: 321 |
I don't understand why this topic provokes so much emotion. The more different space objects we identify and interact with, the more details we will want to take into account when we try to categorize them. And for the above mentioned continuum reasons, none of the categorizations will ever be a perfect fit. However, calling this application of nomenclature "not a perfect fit" is like calling Mariner 1 "not a total success." The great contribution of the IAU's effort to name these various classes of body is that one day it will be remembered as a failure in nomenclature the way that cold fusion is remembered as a failure in application of the scientific method. "Never let scientists name your product." The interesting thing is that star nomenclature has proceeded fairly smoothly. Supernova, white dwarf, neutron star, pulsar, black hole -- all of these terms were examples where the scientists basically got it right on the first try. But even before 2006's controversy, we had "plutinos", "KBOs", and "TNOs". Now we have "dwarf planet", "plutoid", and two controversial attempts at "planet". I think part of the answer is that people didn't previously have any concept of any of those star types until scientists theorized or discovered them. The terms described new things; they didn't replace terms. But we've had fully six terms for denoting Pluto (not counting "Pluto" and "minor planet") with one of those terms given two new definitions. Any way you slice or dice it, you can tell when a good job is being done and when a poor job is being done, and seven categories for Pluto is not a good job being done. It's horrendous. |
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Jun 19 2008, 08:23 AM
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#4
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Member Group: Members Posts: 307 Joined: 16-March 05 Member No.: 198 |
The interesting thing is that star nomenclature has proceeded fairly smoothly. Supernova, white dwarf, neutron star, pulsar, black hole -- all of these terms were examples where the scientists basically got it right on the first try. But even before 2006's controversy, we had "plutinos", "KBOs", and "TNOs". Now we have "dwarf planet", "plutoid", and two controversial attempts at "planet". I think part of the answer is that people didn't previously have any concept of any of those star types until scientists theorized or discovered them. The terms described new things; they didn't replace terms. The two cases are not parallel. Nobody (so far) has attempted to re-define the word "star" by excluding neutron stars and white dwarfs from being regarded as stars. A white dwarf, for example, is (AFAIK) still regarded as a kind of star. That is, "white dwarf" is merely a subcategory of "star". (Even a black hole, for all its outwardly bizarre characteristics, is at its heart basically a star. A DEAD star. Just as neutron stars and white dwarfs are (nearly) dead stars. That is to say, they are the cinders/corpses of the objects they used to be--back when they were still alive and well and burning hydrogen.) In contrast, the IAU definition specifically excluded "dwarf planets" from the category of "planet". As Betelgeuze pointed out earlier in this thread, that was "like saying a human dwarf is not a human". That is, such an exclusion would carry the implication that "planet" and "dwarf planet" were fundamentally different kinds of celestial objects, just as "star" and "planet" are (intermediate types like brown dwarfs notwithstanding) fundamentally different. ====== Stephen |
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Jun 19 2008, 02:44 PM
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#5
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Senior Member Group: Members Posts: 1018 Joined: 29-November 05 From: Seattle, WA, USA Member No.: 590 |
. . . that was "like saying a human dwarf is not a human Since this is another "argument from linguistics," I want to point out that it's kind of unreasonable. Note that a lightning bug is not a kind of lightning. There's probably some instance elsewhere in scientific nomenclature where a dwarf X isn't actually an X. A black hole, by the way, is a very special thing, in that the dividing line really is so sharp that a difference of a single kilogram of mass (in theory) separates a black hole from a neutron star. As a paper in Science a year or two ago showed, there's even a fairly sharp line at the lower end of stars -- a minimum mass for fusion. I'll bet there's a bright line in planetary mass too -- above which you always get a gas giant -- so there might even be a range of "forbidden" planetary masses. That would be one heck of a bright line. We'll just have to get more data to be sure. --Greg |
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Jun 19 2008, 05:28 PM
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#6
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Senior Member Group: Members Posts: 2530 Joined: 20-April 05 Member No.: 321 |
Since this is another "argument from linguistics," I want to point out that it's kind of unreasonable. Note that a lightning bug is not a kind of lightning. There's probably some instance elsewhere in scientific nomenclature where a dwarf X isn't actually an X. Well, with a few years of professional experience in linguistics and a PhD minor in it, I'll chime in. A noun phrase has a head noun, and it's usually the case that the thing referred to by the noun phrase is also an instance of the class of the head noun. And "lightning" is not the head of "lightning bug"... "bug" is. And a lightning bug IS a kind of bug. There are also cases of noncompositionality, where a lexical term with multiple word-tokens both of which happen to be words on their own are nonetheless totally unrelated semantically: The poker hand "full house" is not a house. So while in principle a shadowy committee could create a term like "dwarf planet" and then claim that it is as unrelated to planets as Long Island iced tea is to actual tea, that would be disingenuous in this case, and I don't think anyone's claiming it. |
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Jun 19 2008, 10:32 PM
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#7
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Senior Member Group: Members Posts: 1018 Joined: 29-November 05 From: Seattle, WA, USA Member No.: 590 |
Sigh. People are getting too serious again; it's probably time for someone to delete the thread.
My point was that in language the whole isn't always the sum of its parts. On reflection, trying to work in the Mark Twain quip about lightning/lightning bug was probably too cute. Here's one I'm sure you'll love. A "minor planet" isn't a planet. Anyone disagree? :-) Summary: If you want to argue the term is bad, do it on a scientific basis. Don't appeal to linguistics. --Greg |
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