What’s Wrong with “Dwarf Planet”?

Pluto Flames

So, I’m on the distribution for a listserv that includes a number people who are involved in public outreach in astronomy. Most of the time, the discussions are aimed at things that concern such professionals: astronomy news, tips on lecturing, what materials are available, who’s showing/talking about what, meeting announcements and that sort of thing. But, occasionally there are topics that crop up that cause the same reaction you’d see if you tossed red meat to a group of starving wolves.  The “Pluto is/is not a Planet” topic is one of them.

Most of us just roll our eyes and hit “delete” or “next” when that topic comes up. This is because the same folks rehash the same arguments over and over again. It gets tedious and nobody ever wins. In fact, everybody loses because the list gets taken up with the circular arguments and exclamation points for a while and many of us stop reading or posting to it until the flames die down.  I’m not saying we shouldn’t have the discussion, but that maybe the topic is just not going to be solved by yelling and insisting that laws were broken and children are being hurt deeply because Pluto isn’t a planet any more, etc, etc. ad nauseum.

An artist’s conception of Charon (with Pluto in the background) against the backdrop of the Milky Way. The plumes and brighter spots depicted at left on Charon are thought to be created as water (with some ammonia hydrate mixed in) “erupts” from deep beneath the surface. The material sprays out through cracks in the icy crust, immediately freezes and snows crystalline ice down onto the surface, creating a water-ammonia hydrate ice field. Such fields were detected and studied using the near-infrared imager on Gemini North. (This composite image includes Pluto and Charon models (enhanced), courtesy of Software Bisque. www.seeker3d.com, with plumes and ice fields added by Mark C. Petersen, Loch Ness Productions. Star field from DigitalSky 2, courtesy Sky-Skan, Inc.) (Click to embiggen.)
An artist’s conception of Charon (with Pluto in the background) against the backdrop of the Milky Way. The plumes and brighter spots depicted at left on Charon are thought to be created as water (with some ammonia hydrate mixed in) “erupts” from deep beneath the surface. The material sprays out through cracks in the icy crust, immediately freezes and snows crystalline ice down onto the surface, creating a water-ammonia hydrate ice field. Such fields were detected and studied using the near-infrared imager on Gemini North. (This composite image includes Pluto and Charon models (enhanced), courtesy of Software Bisque. www.seeker3d.com, with plumes and ice fields added by Mark C. Petersen, Loch Ness Productions. Star field from DigitalSky 2, courtesy Sky-Skan, Inc.)

Pluto is a planet. Better than that, it’s a special case of planet called dwarf planet. That’s pretty much the take-away message from the IAU vote of a few years ago. There’s a lot of other stuff in the current definition that IAU posted about how we define planets (and you can read it here).  People LOVE to argue about the rest of the definition and how it might be used to exclude Earth, and how the vote wasn’t fair and yadda yadda yadda.  But, the essential message here is that Pluto and worlds like it are now deemed dwarf planets.

This makes perfect sense to me. We have dwarf galaxies. We have brown dwarf objects sitting in the cellar of the star classification schema that nobody would dream of saying fit into the canonical definition of “star”.  We just accepted that one and moved right on to study these BDs and figure out where they fit in the evolutionary schema of the cosmos.

So, why not dwarf planets?  They certainly occupy a special shelf in the solar system bodies collection. Science is partly about classifying objects, and so what the IAU did (and I do understand that it doesn’t sit well with some people) is to refine the classification — just the same way we do with other sets of objects.  The finer the classification, the more easily we can define the things we see and — THIS IS IMPORTANT — understand their origins, evolution, and future.  This is all part of science. The definition is merely the name we plaster on it that tells us, in a sort of nice shorthand, that “this object is thus and such, and it did this and that, and it will end up as one of those.”

I know this isn’t enough to keep the wolves from continuing to tear away at the dead horse of what they think is a bad decision by the IAU.  There’s no pleasing some people until you finally give up and say, “Okay, you’re right. All the rest of us are wrong, the whole world is wrong, only your opinion counts in the marketplace of ideas, so can we get back to work now?”

But, think about this: the definition of planet, and Pluto in particular,  is a teachable moment. It’s a lesson in how scientists classify things and how we come up with the schemas that we use to identify and understand things in nature. THIS is the lesson that kids (and a lot of adults, apparently) need to learn. It’s not so much the name as what the name stands for.  And, it’s not the time or place for a lesson in screeching like a banshee in order to get your point across, or, in the case of some states in the U.S. the time to do silly crap like pass resolutions that Pluto is a Planet. THAT is a colossal waste of time and money, shows students that science is somehow governed by political laws, and makes about as much sense as the legislative body deciding to declare that Pi is equal to 3 or that from henceforth on, dogs shall be declared cats.  Sheesh.

6 thoughts on “What’s Wrong with “Dwarf Planet”?”

  1. Your statement, “Pluto is a planet. Better than that, it’s a special case of planet called dwarf planet” would make sense IF the IAU had in fact approved that. But they didn’t. By voting down resolution 5b, the umbrella resolution that placed both classical planets and dwarf planets under the broader category of planets, they adopted a definition that makes no sense, as it specifically states that dwarf planets are NOT planets at all. That is completely inconsistent with the use of the term “dwarf” in astronomy, as dwarf stars are still stars, and dwarf galaxies are still galaxies. And it makes no linguistic sense, as it is like saying a grizzly bear is not a bear. Why should people settle for a flawed, vague definition like that that creates more confusion than it resolves?

    I strongly object to your description of resolutions passed by states supporting Pluto’s planet status as “silly crap.” That demeans efforts of people like Siobhan Elias, a resident of Streator, Illinois, the birthplace of Pluto discoverer Clyde Tombaugh, who worked hard to get the Illinois Senate to pass such a resolution. Passing it is a symbolic act, a protest saying no one should have to blindly adhere to an “authority” if that authority does a poor job in creating classification schemes and reaching decisions. If the 2006 IAU General Assembly and subsequent dismissal of worldwide concerns over this debate over the last two years are examples of anything, they illustrate exactly how scientists should NOT operate in classifying things.

    All they have to do is amend the definition to include dwarf planets as a subclass of planets, yet the IAU adamantly refuses to do this. Why is doing this problematic for them?

  2. Laurel, I stand by the statement that having legislators determine scientific definitions like the one where a state is calling Pluto a planet as crap. But let me restate it: It’s a waste of time and money and is unscientific. I meant no disrepect to the people who want to honor Tombaugh — I think there could have been a much better way to do this, but having legislators pull these stunts just cements in the public mind that science is up for legislation (and perhaps for sale) to anybody with enough time and/or money to influence a few votes. That’s not the way science works. Appeals to emotion (such as telling us children will be harmed because Pluto’s not a planet anymore (which I’ve seen in many arguments) or appeals to honoring the discoverer of Pluto (who, I think might well have not approved of having a non-scientific body pass a LAW about the object he found) are not any better. I am arguing for scientific accuracy and standards of science nomenclature to be strong — not that we let legislators determine what is and isn’t a planet/correct definition of pi, etc.

    As for the IAU, I am aware of the political machinations in that body’s decision about Pluto, and perhaps what they did could also be termed crap. They have a chance to fix this and perhaps they will. However, the Illinois legislature — or any state legislature — isn’t any better a “blind authority” than the IAU, yet you would suggest that we bow to what they want us to think? I’m not buying it.

    As you suggest, the IAU could fix this by accepting that dwarf planets are a class of planets. And, in my mind, they could also rethink their definition of planet so that it makes more scientific sense. I’m not a member, so my feelings have little weight in the matter. But their actions dismayed me, too.

    I appreciate your writing in response to the blog entry about this — whether we agree or not, it does keep the subject in the air and I still maintain that this is a teachable moment — both from the standpoint of how science works as well as that of not submitting to blind authority in matters scientific — whether that blind authority is a statehouse crew tha wants to please a constituent or a scientific body with responsibility for keeping names and classifications straight for both science and the public.

  3. I disagree that your views or the views of non-IAU members have little weight in this matter. They do. The IAU claims they’re interested in communicating astronomy with the public, but the way they have handled this, not just at the General Assembly, but in the two-and-a-half years since–has been with complete contempt and disrespect toward the public. The Illinois legislature is making a symbolic statement; they have no illusions that anyone is required to follow their proclamation. Unfortunately, the same cannot be said of the IAU, which expects the whole world to blindly bow to its decree.

    Significantly, neither I nor any of the many people I know of who contacted the IAU about this ever received even an acknowledgment of their communication and concern. The leadership of the IAU has already stated it does not want to reopen this issue. The IAU made the mess, but they don’t want to take the responsibility for cleaning it up. To me, this is a problem.

    For more on scientific arguments on why Pluto is a planet, feel free to visit my blog at http://laurele.livejournal.com

  4. Laurel, your comment that people who have contacted the IAU feel unheard is one I’ve heard before. No idea why they don’t want to respond to people but as you point out, they’re standing by their decision, however flawed it may be. It strikes me that that isn’t any more scientific than what the Illinois lege did. I don’t know. It’s unfortunate though, because the last action left things quite unsettled, as we’ve all noticed.

    I was amused by the state of New Mexico’s decision on the Pluto matter — they’ve designed Tombaugh’s birthday Pluto Planet Day.

    Illinois’s decision may be symbolic, but it still gives the impression that science can be fiddled with by lawmakers. That is no more fair than the IAU decision to not revisit the issue. Will you also stand by and let the Illinois lege decide that the chemical element Iodine should be reclassified as a liquid? Or be renamed Illinoisium? Probably not. They wouldn’t, but this is essentially what Illinois has done with the classification of Pluto. Let the science world figure it out. It may be slow and the Pluto/planet decision disturbing in some ways, and some members may be pigheaded about it, but it’s in the realm of science, not political voting or popular emotion.

    Thanks for coming back to discuss this further.

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