One question I hear a lot, is what about Pluto? Do I agree with the decision to reclassify Pluto as a Dwarf Planet?
I was a staunch defender of Pluto’s planethood. Pluto had always been a planet (at least in my lifetime) and I had trouble visualizing a universe with Pluto as a planet.
As a teacher, I depended on Pluto with “My Very Excited Mother Just Sent Us Nine Pizzas” as the memory trick for learning the names of the planets in order from the Sun.
In 2005 astronomers put the nail in Plutos status coffin with the discovery of a third large Kuiper Belt Object (KBO), Makemake. Eris, initially thought to be larger than Pluto, had already been added as the 10th planet. But Makemake gave a hint that there may be many more Pluto-size objects out there. This dwarf planet is about two-thirds the size of Pluto.
Should they all be counted as planets? that;s when the International Astronomical Union stepped in and reclassified Pluto and Eris as dwarf planets.
So I have to ask myself, what do I teach?