Transcript of “Pluto’s Planetary Fate? Not Great”
You’re listening to A Way with Words, the show about language and how we use it. I’m Grant Barrett.
And I’m Martha Barnette. Back in 2006, the International Astronomical Union had a vote on the definition of the word planet. And you may remember that there was lots of arguing about this.
And in the end, the ninth planet, Pluto, was stripped of its title. And this was really big news at the time. And there were a lot of people, including me, who were kind of upset. You know, we thought, wait, we’ve learned in school that there are nine planets. And we even had mnemonics to remember all their names, like my very educated mother just served us nine pizzas.
What are we supposed to say now? My very educated mother just served us nachos.
And Grant, linguists also took note of that brouhaha, didn’t they?
That’s right. In January of 2007, the American Dialect Society, which I am a part of, voted Pluto as one of its Pluto-related words of the year because there were other words related to Pluto, like Pluton, possibly a category of trans-Neptunian objects that did not warrant the designation as true planets.
Right. And if you got Pluto’d, you were demoted or devalued, right? I mean, we rarely hear this word.
Struck down.
Exactly. Well, the story of how Pluto got kicked off its planetary pedestal is told in a really delightful book that was written a few years ago by the astronomer who set all this in motion.
It’s called How I Killed Pluto and Why It Had It Coming, which is so intriguing, right? It just makes you want to pick it up.
But it’s by Mike Brown, who’s an astronomer at California Polytechnic Institute in Pasadena.
And in 2005, Brown and his colleagues announced that they had discovered an object that was a whole lot bigger than Pluto and even farther away.
And so for a short time, Brown was hailed as the discoverer of the 10th planet.
But there was a problem with this.
There was a problem with the definition of the word planet because astronomers had never formally agreed on what exactly a planet was.
And in fact, I learned that in the early 1800s, school kids were taught that there were 11 planets.
And for a brief time after that, they were told that more than 20 planets had been discovered.
Now, most of those were soon reclassified as asteroids.
So anyway, the word planet itself comes from the Greek word for wanderer.
And that’s because unlike the stars that move in fixed constellations, planets wander right through those patterns.
And Brown’s discovery forced scientists to wrestle again with the definition of what exactly these celestial bodies are.
And eventually they decided that to be called a planet, basically it had to orbit the sun, it had to be round, and it had to be big enough to be gravitationally dominant.
That is, it’s big enough to clear its orbit of other debris.
And as much as it pained Brown to conclude that this new object wasn’t a planet, he was among those arguing that it simply didn’t meet those criteria.
And if that new one didn’t, then Pluto certainly didn’t.
And Brown got lots of angry letters from schoolchildren and even some death threats.
And I’m leaving out a lot.
The book has a lot of humor. It even includes a little whodunit, which is very cool.
It’s got a ton of personal memoir about his own experience becoming a husband and a father.
But Grant, I think it’s this fascinating read about our struggle to classify nature, to break all of that down into manageable chunks and try to squeeze it into words, words that we can use to help understand it.
Definitions really matter.
They do indeed. And I remember the vote at the American Dialect Society about whether or not Pluto should be word of the year for 2006.
And the arguments were fierce and people were full of energy and vigor to talk about this.
So it wasn’t just the astronomers who were having this big debate. There were no death threats.
Well, I should add one more thing about this book, How I Killed Pluto and Why It Had It Coming.
Since it was published in 2010, Brown and a colleague have announced that their calculations suggest that there really is a planet nine out there that’s several times bigger than the Earth.
And they’re hopeful that when a new state-of-the-art observatory opens in Chile in 2025, the discovery of the ninth planet won’t be far behind.
Oh, that would be so amazing.
I can’t wait.
Wouldn’t it be cool?
Whatever you’re reading, Martha and I love to hear about it.
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