maybe it's the astrophysics degree, maybe it's my previous life as a science educator/communicator, but i'm still rubbed the wrong way by the language we use talking about pluto and its classification shift from planet to dwarf planet. i hear the word "demotion" a lot--as though pluto did something wrong to be put in a lesser category--and the emotionally charged nature of it grates on me. i always taught this as the scientific method at work. when we first saw pluto we thought it must be a planet, and as our telescopes got more powerful and we found more similar objects to pluto and learned more information, we came to understand that it's different from the other planets in our solar system and fits better in a dwarf planet category.

in this section bryson references the international astronomical union's (iau) meeting to formally define a planet and add the dwarf planet category, and i'm reminded of my undergraduate days when astronomers were working on a more detailed formal definition of a galaxy to help differentiate between the smallest dwarf galaxies and the largest star clusters. the field of astronomy is so big, and there are so many objects out there, and our technology gets better and better all the time and shows us even smaller and fainter objects that we couldn't previously imagine, and our language and categories for these things change along with them.

anyway. i'm curious if there's any other scientific discoveries or classifications that suffer from a similar cultural sentimental backlash that pluto gets, and i'll be keeping an eye out for that kind of emotionally charged language around classification changes throughout the rest of this book.