Pseudo-history and the definition of a planet

[mmcirvin]

This Planetary Society article about the proposed redefinition of "planet" says:

In the past, no term in astronomy had seemed as clear cut as a "planet." There were nine, six of which had been known for several millennia, and while no formal definition was available, none seemed necessary. Planets seemed intuitively obvious, and if more were discovered somewhere in the universe, both professionals and lay people confidently assumed that they will know one when they see one.

factitiouslj points out that, at least in 1828, the definition was different:

The book First Steps to Astronomy and Geography, from 1828, listed the planets as "Mercury, Venus, the Earth, Mars, Vesta, Juno, Ceres, Pallas, Jupiter, Saturn, and Herschel." Apparently the name "Uranus" hadn't caught on yet.

So at least one textbook was listing four asteroids (three of which may be planets under the proposed IAU definition) as planets, 27 years after astronomers started finding asteroids and before Neptune was discovered. I suppose the demotion happened once they started to realize how many there were. If the definition of a planet was ever considered intuitively obvious, it was an obviousness that was subject to change.

Comments

[mmcirvin.livejournal.com]

I guess Herschel's name "Georgium Sidus" didn't catch on.

[mmcirvin.livejournal.com]

...Hmm, Wikipedia points out that there were obvious political problems with that name outside Britain. It also says that the name "Uranus" was actually catching on by the late 1820s, though it was far from universal.

[reverendluke.livejournal.com]

Yeah, it wasn't real popular in France for some reason.