Kids get the Pluto thing

I just changed my mind about Pluto after speaking to a class full of six to seven year olds.

This was my position before I went to face the weenies. (i) Given that the IAU was taking a technical decision, a pretty good one was made. Maybe not ideal, but you can’t go round in circles forever. (ii) However, Pluto is a cultural object as well as a scientific one, so one should somehow respect this. (iii) At the same time, mass prejudice should not be allowed to bully science into one position or another. (iv) My personal opinion is actually that whether or not Pluto is a “planet” is not a suitable subject for standardisation, and in fact almost has no meaning. (v) Conclusion – popular culture can call whatever it likes a planet. Hey, no problem. Just don’t tell us what we must call a planet.

So whats changed ? Two things. First, normal folk, including kiddie-winkies, understand the Pluto thing perfectly well, and there isn’t a problem. Second, they want us to tell them the latest stuff, and are happy to accept it. In fact we have a responsibility to decide and to tell them.

Today I went to give a talk to Primary School kids. Basic stuff – Earth, Moon, Planets, the stars are Suns, what is a shooting star etc etc. I love doing this. As I came to Pluto, they said “So is Pluto a planet ? Cos you all voted it out ?”. My answer was “Well, kinda. Anybody know why we did that ?” About nine hands went up and several kids just blurted out “Cos we keep finding new wee ones”. Spot on.

So the pictures I had ready were just right. First a picture of Pluto; then a montage of Pluto and Eiris and Ceres, labelled “dwarf planets”. Then I said, “Well, so there are lots of planets. There are eight big planets, and lots of dwarf planets. Pluto was just the first dwarf planet we found”. Lots of nodding.

Done deal. Simple. And really cool. Wow ! There could be loads of dwarf planets ! Yup.

8 Responses to Kids get the Pluto thing

  1. What you didn’t explain is that the IAU determined that dwarf planets are not planets at all, a linguistic impossibility. It’s very likely the kids innately understand the definition as meaning dwarf planets simply are small planets. This is how the definition should have been written and it is what most people think the IAU definition means. From your description, it almost sounds like you agree with this conception that dwarf planets are a subcategory of the larger category of planets as opposed to not being planets at all.

    People don’t want to just be told or spoonfed information and then blindly accept it. They want to understand the reasoning and logic behind information and classifications, and they deserve to know the fine points of how the decision was made and the fact that there are legitimate dissenting views.

    Personally, I will be happy if in 2009, the IAU changes its definition to include dwarf planets as a subclass of planets. I also think the requirement of “clearing its orbit” is sloppy and needs to be changed because none of the planets fully clears its orbit, meaning under a literal interpretation of this definition, there are no planets.

    I give credit to Al Witzgall, the instructor of an astronomy class I am currently taking, for his planet definition, which should be seriously considered and adopted by the IAU. His definition states that a planet is “a non-self luminous spheroidal body in orbit around a star.” It’s that simple and uncomplicated. Under that broad description, we can include many subcategories, such as terrestrial planets, gas giants, and ice dwarfs or dwarf planets.

  2. andyxl says:

    Gee. What took you so long ?

  3. Stuart says:

    Laurel, when you say “non-self luminous” I assume you are (arbitrarily) referring to one particular, narrow part of the electromagnetic spectrum? Secondly, where do you draw the line for “spheroidal” under this definition? The Earth is a bit oblate after all.

    In the way you presented it, Al Witzgall’s definition doesn’t seem any better to me. Ultimately, the fine points of the decision don’t matter because there is a whole range of types of objects in the real Universe and any distinction that makes some objects planets and some not is going to be arbitrary. Why does arguing over semantics matter so much to you in this case?

  4. “Non-self luminous,” according to Mr. Witzgall, means the object is not a star, and self-sustained nuclear reactions do not occur within it.

    “Spheroidal” does not necessarily mean perfectly round. It encompasses both round and oblate objects that have achieved hydrostatic equilibrium, meaning they have enough gravity to have pulled themselves into a round or oblate shape, clearly distinguishable from a shapeless asteroid.

    I question your statement that “any distinction that makes some objects planets and some not is going to be arbitrary.” The distinction between a brown dwarf and a planet is hardly arbitrary; neither is the distinction between an object that has achieved hydrostatic equilibrium and one that has not.

    Contrary to some people’s views, semantics do matter. How we define objects, issues, ideas, etc. is central to the way we study and value them. As a writer, I am particularly sensitive to this. Definitions need to make sense and have sound reasoning behind them. When students write research papers, one of the first things they are asked to do is define the terms they will be using. Semantics can easily be misused to deliberately alter people’s perceptions, as can be seen from political campaigns, government policies, etc. New Horizons might not have received funding if it was designed to study a minor ice ball as opposed to a planet.

    The bottom line is, words have power. As I stated in one of my blog entries, “he or she who defines the terms wins the debate.”

  5. Vinay says:

    It is true what Laurel Kornfeld says — the IAU voters screwed up. This is also the view of Owen Gingerich, who should know! See, for example, his article in the Boston Globe,

    Not only is the current definition of a “planet” too ambiguous, with all the gratuitous dynamics thrown in, but the Pluto type objects have been essentially left undefined. Remember, “Plutonians” was voted down. What you list as your commonsensical view, Andy, is indeed commonsensical, but the official definitions are rather more muddled.

  6. andyxl says:

    Owen is a paid up pro, so he gets a vote, but only one. Like me, he is not an expert on planetary astronomy. He is an expert on astronomical history. (He was here two weeks ago and gave us a fabulous seminar !)

    So… it seems to me that the cultural issue is evaporating. Ordinary folk are happy with “planet” and “dwarf planet” as basic concepts. There is no public issue, no cultural issue, no scandal. This doesn’t necessarily mean that the precise technical definition of those terms is perfect. But thats then just a technical matter for the IAU. Why on earth should such a technical matter be decided by an internet petition ?

    Still trying to think of a Limeric for Stuart

  7. andyxl says:

    oops slight gaff above. Owen did of course chair one of the key IAU committees last year – so he is especially qualified to comment on the debate ! But he still only has one vote on the answer …

  8. The public and cultural issues are evaporating? And your evidence for this is a talk to primary school kids? Sorry, but you’ve provided no real evidence for this claim and have either inadvertently or deliberately fudged the planet vs. dwarf planet issue. It’s not just a technical issue for the IAU. The public intrinsically seems to “get it” that dwarf planets should be a subclass of planets; the IAU or at least those who voted in August 2006 do not. You have been presented with the views of other astronomers, not just those of lay people arguing against the IAU decision but have chosen to ignore their points and not respond to them. Just because you say there is no cultural issue or scandal does not make it so. Neither does a vote of 424 out of 10,000 motivated more by political than scientific considerations. I think you have a surprise in store come 2009.

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