Did you know that Ceres was the OG 9th planet of the Solar System? Discovered in 1801 by Italian Catholic priest and astronomer Giuseppe Piazzi (because astronomy was almost always a side-gig), this now-dwarf planet was originally described as a comet... Probably? (1/5) 
https://twitter.com/DrJeniMillard/status/1419564163534368769
In his own words: I have announced this star as a comet, but since it shows no nebulosity, and moreover, since it had a slow and rather uniform motion, I surmise that it could be something better than a comet. (2/5)
Observations at the end of 1801 confirmed this new object, and Ceres was designated a planet - particularly since it fit with the now-disproved Titius–Bode law, a mathematical oddity describing the spacing of the planets, indicating there should be one between Mars + Jupiter (3/5
But then, more objects were found near Ceres.
Vesta (pictured).
Pallas.
Juno.
Over two dozen objects were found, as astronomers soon realised they needed to distinguish between the large, spherical planets and the pin-point new objects (4/5).
Vesta (pictured).
Pallas.
Juno.
Over two dozen objects were found, as astronomers soon realised they needed to distinguish between the large, spherical planets and the pin-point new objects (4/5).
So, by the middle of the 19th century, these new not-planets not-comets were designated asteroids, and the Solar System was back down to 8 planets (5/5).
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