The alternative was to announce "we now have 10 more planets, and there are probably a bunch more, and we'll probably never really get a definitive number".

That would also have had an impact on the public view of science. Perhaps not as bad, but it would have had an impact.

No, the alternative would be to make up some latin sounding words for planets, dwarf planets, etc. and leave the vulgar planet alone to the standard 9 that we all know are planets.

No that would be an argument to return to the original definition of planets (highly visible celestial objects that migrate across the sky, i.e. the Sun, Moon, Mercury, Venus, Mars, Jupiter, and Saturn).

If you believe in the "standard 9" you're just insisting on returning to a scientific definition of planets but one that is frozen on our scientific understanding from a few decades ago...

As you can see, there are many valid ways to go about understanding what a planet is in a cultural sense.

Right, and then everybody would be in the comments complaining about how "everybody is using a new term for planet and it's ridiculous, just call them planets". It's not a battle that can be won.

This is what should have happened. (And it’s not too late — Pluto will remain with us for a while yet.)

Planets predate modern astronomy. You have to negotiate with the public if you want to change what “planet” means. To most people, in most contexts, it means 8 or 9 specific things that they have specific ideas about, not a theoretical category of infinite objects.

> Planets predate modern astronomy.

If we're segmenting off "modern astronomy" then Pluto wasn't even discovered yet.

And we discovered Ceres long before Pluto. It would be pretty rude to keep excluding Ceres just because we knew about the asteroid belt before we knew about the Kuiper belt.

It’s not about being rude to Pluto so much as about being rude to me.

I’m not a member of the IAU. I don’t adhere to their linguistic prescriptivism, and nobody should expect that I will. Some of their own members do not — the article here explains.

Are you a member of the IAU?

I didn't say anything about rudeness to Pluto, I was talking about Ceres. I like Ceres. I think it deserves some recognition for being known before even Neptune.

By all means, call it what you like and honor it however you like.

I’m not the IAU, and I have no interest whatsoever in emboldening thousands of people to smugly harass you or anybody else about it.

Few things sound more like more science than "planets". Telling people "Well actually 'planet' isn't a scientific term, it's a historical / cultural term" will also significantly reduce their trust and interest in science.

Hey, don’t blame me, blame the IAU for opening that can of worms. I’m just happy calling Pluto a “planet” and would rather the IAU had left me in peace — they’re the ones who want to argue with me about what words I’m supposed to say and when I’m supposed to say them.

I’d encourage you to think about the impact of science fiction on interest in science. Culture is an extremely powerful force. I don’t think your concern would bear out.

There was no do nothing option, the IAU didn't open the can of words. 10 new objects that would be called planets under the old definition were discovered. "Doing nothing" would have led to far more significant changes.

Even if they had to do something, they didn’t need to do what they ended up going for — it was a pretty bad option from a scientific standpoint and a needlessly controversial one.

As the article here explains, the 2006 IAU definition doesn’t really make sense or function as a useful model for what a planet is.