Pluto's not a planet? That may be the verdict for now - but scientists, teachers and the general public will be digesting the International Astronomical Union's definition of planethood for years. Astronomers were quick to raise objections, and the debate over the worlds on the solar system's edge is sure to be revisited. So for now, think of plucky little Pluto's predicament as a classic "teachable moment."
That's how Carl Benoit, editorial director for Illinois-based Learning Resources, sees it. A week ago, the folks at Learning Resources were worrying about how they would rework their teaching aids - including solar system floormats, solar system stamps, their Planet Quest game and inflatable planet sets - to cope with a 12-planet solar system. Now they're wondering what to do about Pluto.
Benoit said the company would review their product line toward the end of the year and decide what needs to be done.
"What I'll recommend is that we'll obviously do the eight planets, and probably do something to label these dwarf planets to make sure everything's correct," he told me. "If I were to say today, would I recommend that? Yes, I would. But from what I'm reading, there could be 120 other dwarf planets."
Even if Pluto isn't on the official list of solar system planets, it may still stay in the educational lineup, Benoit said.
"I think it'd be a good idea to keep Pluto around and explain that this has been a planet for 76 years," he said. "It becomes an educational process, to explain to kids why it was a planet, and now why it's not. ... That's the kind of critical thinking that kids need to be doing when they do science."
That philosophical bent extended even to Patricia Tombaugh, the 93-year-old widow of Clyde Tombaugh, Pluto's discoverer. She told The Associated Press that the IAU's verdict was "disappointing in a way, and confusing."
"I don't know just how you handle it. It kind of sounds like I just lost my job," she told AP from Las Cruces, N.M. "But I understand science is not something that just sits there. It goes on. Clyde finally said before he died, 'It's there. Whatever it is. It is there.'"
She provided yet another aphorism to the Reuters news service: "Clyde would have said, 'Science is a progressive thing, and if you're going to be a scientist and put your neck out, you're apt to have it bitten upon.' He was a good scientist, and he knew how to judge things."
Reuters also gathered reaction from the National Air and Space Museum in Washington. Eleven-year-old Michael O'Sullivan, visiting from Garden City, N.Y., was amazed to hear the news. "Seriously! Pluto is not a planet?" he asked.
After a moment of thinking, he told the reporter: "At least Pluto the dog doesn't have to compete with the planet anymore."
The Disney cartoon canine has often crossed paths with the planet - in fact, the story goes that Walt Disney named the character Pluto to capitalize on the news of Tombaugh's discovery. During the IAU's crucial session, astronomers reportedly waved Pluto plush toys around to demonstrate their solidarity with the onetime planet.
Disney returned the love, according to Reuters: "Pluto is taking this news in stride," Disney Co. spokesman Donn Walker said, "and we have no reason to believe he might bite an astronomer."
If the decision sticks, schoolkids will have one less planet to memorize - but they'll also have to come up with new mnemonics to replace the old standbys, such as "My Very Eager Mother Just Sewed Us New Pajamas." We delved into this burning issue when it looked as if Xena might be added to the list of planets, but you're welcome to revisit the issue, either by submitting your comments here, or adding to the more than 1,000 postings on MSNBC's message board.