That’s a definitional question, though, is it not? I don’t think any facts actually changed.
Comment on Can you think of any now?
ghen@sh.itjust.works 4 weeks ago
The fact that we thought Pluto was a planet seemed absolutely insane at the time but none of the kids could question the adult in the room when the stupid rock is literally not even staying in its own lane
fodor@lemmy.zip 4 weeks ago
JackbyDev@programming.dev 4 weeks ago
Yes. Ceres was considered a planet when discovered in 1801 and around the 1950s began to be classified as an asteroid. It is now considered a dwarf planet like Pluto. It’s the largest thing in the asteroid belt but is still sort of planet shaped.
ghen@sh.itjust.works 4 weeks ago
Okay then maybe the electron shells model of an atom. That was taught as fact and it’s definitely not true even though it’s still useful
echodot@feddit.uk 4 weeks ago
It doesn’t help that planet has such an incredibly vague definition. Earth is a planet but so is Jupiter but other than being spherical they don’t have anything in common. In terms of similarities, Pluto is much more like Earth then Jupiter is like Earth, at least Pluto has a solid surface.
ieGod@lemmy.zip 4 weeks ago
It’s not vague at all. It’s a classification that needs to meet three criteria. The lack of this classification is why it was taught that pluto was a planet, but once these things were formalized in 2006 it became clear that pluto no longer met the criteria.
en.wikipedia.org/wiki/IAU_definition_of_planet
echodot@feddit.uk 4 weeks ago
Yes and I know that Pluto fails the final test, although it’s a bit difficult to really to say in what context that matters, because it’s in the capable which is incredibly diffuse anyway.