Delving into the Nine Eight Planets

You know those old people who are set in their ways? The “back in my day” and “you kids have it easy” types? I see them and wonder how they got to be like that, and then one day, I realize I am like that myself, and never saw it coming.

Our third-grader’s teacher sent home an email outlining what would be happening in school next week, a short week with a mixed up schedule. She listed the topics they’d be cover over the week and one line jumped out at me:

Science: Delving into the 8 planets.

Let me tell you, kids have it easy today. Back in my day, for instance, we had nine planets. I don’t how the youth of this generation manages to get away with a mere eight. Not only that, when I was my third-grader’s age, Jupiter had maybe a dozen or two moons. Today it’s got something like 69 of them.

I’ve written before about how my love affair with astronomy began in first grade when I discovered a book called–wait for it–The Nine Planets by Franklyn M. Branley. For those younger generations reading this, that “ninth” planet was Pluto.

I scorned the email. The definition the Little Man was given for a planet was “a large ball-shaped object made of gases or rocky material.” Take a look at the photos of Pluto and tell me that it is not a large ball-shaped objects made of gases or rocky material. I’ve seen baseballs that are less ball-shaped than Pluto. I wanted to reply, jokingly, to the teacher’s email and point this out. But then something else occurred to me.

“Why isn’t Pluto a planet anymore?” the Little Man would likely ask me, and I realized this was an opportunity. You see, the science and the scientific method are self-correcting. What we know about the universe changes as the we get new and better information. Pluto is a good example of this change. Pluto was considered a planet for decades, but as our instruments got better, and our ability to measure things like mass and orbit improved, it became clear that Pluto shared more with minor planets than with full-fledged planets, and so astronomers corrected themselves using the new information.

Of course, I could imagine the conversation taking a different turn as well. I imagine myself asking the Little Man, “How do you think scientists found out about Pluto in the first place?” and the Little Man (who is really not so little anymore) shrugging casually and replying, “Easy: they Googled it.”