On Pluto


Am I alone in having no particular opinion as to whether Pluto should be considered a planet? I just can’t see what cartoon dog I have in this fight.

Am I also alone in thinking that there’s something slightly unsettling about the sudden outpouring of sentimental support for Pluto’s full-planet status? I can’t put my finger quite on it, but it strikes me as vaguely anti-intellectual. Perhaps it’s that the actual categorization of Pluto as planet, dwarf planet, or non-planetary body is wholly a matter of terminology, and not really a question of any scientific moment. I’m not sure whether the heavy layers of irony involved make matters better or worse.


I’m sure you’re not alone in your lack of opinion. But as someone who’s older—and who was brought up on Pluto as planet number 9—I have to admit to some distress at this latest ruling, akin to the feeling I have when I look at new globes of the world and see countries I never learned about in grade school.

I’m sure it’s probably just a combination of nostalgia and a dislike of change. But for me, there’s something inherently satisfying about the number nine. Is there a mathematical reason for this feeling? I have no idea. But eight just feels…wimpy. Nine planets feel…right.


I think the problem is that the IAU is toying with settled cultural expectations for no real reason— no new data has been discovered, and Pluto hasn’t suddenly done something different to merit a change in status. From the non-scientist’s perspective, it’s change for the sake of change (which some of us are disinclined to like). Since it’s a question that really doesn’t matter, why not just apply the new definition prospectively and grandfather Pluto in? The IAU hasn’t “proven” Pluto’s planethood to be false, they’re just defining it to be false. It’ll take more than that to change the minds of several generations of schoolchildren who were taught that it does count as a planet.

Kinda like the metric system— scientists may find it more useful than English measurements, but “my car gets forty rods to the hogshead, and that’s the way I likes it.”


I certainly don’t care. Pluto will always be there for me whether it is a planet, a pluton, or a dwarf.


The New Yorker (July 24, 2006) had an article by Alec Wilkinson entitled “Tenth Planet” which sort of addresses this question. (For all I know, James, this article is what inspired your post.) Caltech professor Mike Brown, who’s discovered several of the solar bodies that threaten Pluto’s status, had this to say:

“When I used to argue for eight, I felt as if there was a public sentiment that you couldn’t get rid of Pluto. If you did, you were a mean person, is what it felt like. I wondered why there appeared to be an emotional attachment to an inanimate object that most people who are arguing about had never seen. The epiphany was understanding that people love planets the way they love dinosaurs. Planets are like continents. ‘Continent’ is a good geological word, but, like ‘planet,’ it has no scientific meaning whatsoever. There is no scientific reason why Asia is a continent and Europe is a continent, and India is not. If you said you were going to take away Australia as a continent, people would not like it.

“The concept of a planet is also part of the mental geography of the world around us. Pluto doesn’t fit as a piece of science, but it does culturally. Initially, I thought, We can’t have it this way, we can’t have culture determine such questions. Then I thought, There are places where science reigns, and others where culture does. Science doesn’t have to win this one. So I thought, I’m willing to give up the hard-nosed science view of what a planet is in lieu of a cultural view, and that view includes Pluto, so it includes anything bigger than Pluto.”

That being said, for all the fulminations, I’m sure Pluto’s status matters less to most people than, say, the Red Sox’s chances of reaching the playoffs.