0, 0, 1, 2, 12, 9, 5, 2, 0
Twelve planets in the Solar System? I read that the International Astronomical Union is voting on such a suggestion, for various reasons, one of which is to keep Pluto as a planet. It would also involve promoting asteroid Ceres, giving moon Charon its own planetary papers, and calling an object “nicknamed Xena” out beyond Pluto a planet. Pluto, icy and quiet way out there, likely doesn’t care how we classify it, but in any case 12 all together would take some getting use to.
I’m not sure I’d ever quite be able to. Certain numbers go with certain things. States: 50. (Admittedly, only since just before I was born.) Apostles, Angry Men, Months: 12. Virtues and Deadly Sins: Seven each. Hills of Rome: Seven. Four Marx Brothers (no one counts Gummo.) Three Stooges.
Nine planets. I memorized their names and order from the Sun in second grade. Not long after that, I knew how many moons each had, according to the Junior Encyclopedia Britannica, published more than a decade earlier: 0, 0, 1, 2, 12, 9, 5, 2, 0. And only Saturn had rings. There was no mention of Kuiper Belts or Oort Clouds, though the Asteroid Belt got its due.
But discovery moves forward, or at least it should. Those numbers were outdated when I learned them, with Jupiter and Saturn especially fertile for the discovery of rocks in orbit around them. I suppose it was part of learning that printed material, some kinds faster than others, gets dated.