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by DukeBaset 1905 days ago
It's called Pluto and it's a planet - Jerry
3 comments

I think your counting's off: if you want to count dwarfs then Ceres would be "Planet 5", in which case "Planet 9" would be Neptune most of the time, since only a small part of Pluto's orbit crosses inside Neptune's.

Pluto's number would also depend on the current location of at least Quaoar, Haumea and Makemake, since I know their orbits cross inside Pluto's. Pluto may also swap numbers over time with others, like Sedna, Eris, Gonggong, Orcus, Salacia, Varda, Ixion, 2003 AZ84, 2002 MS4, 2002 AW197, etc. since they have quite low perihelia (30 to 40 AU) so may also cross inside Pluto's orbit.

Dwarf planets seem to be lucrative business for those who sell wall posters of the solar system. I would hate having to learn all of their relative locations and interactions in school!

> Dwarf planets seem to be lucrative business for those who sell wall posters of the solar system. I would hate having to learn all of their relative locations and interactions in school!

That seems to have been the main reason the majority in the IAU voted to make dwarf planets not considered actual planets. Can't really say I agree with the mindset - it overly simplifies our solar system, as well as making the rocky planets appear more similar to the gas giants than they actually are (a problem in a lot of images of the solar system as well).

It's funny to see the number of people who believe the definition was just following scientific facts, when the vote came down to personal preferences over nomenclature. It's one of the more common examples you run into where modern day scientism has trouble distinguishing what is and what isn't science.

Parent quoted a line of a Rick&Morty episode and was probably not serious ;)
Personally - even if the comment wasn't serious I am glad it received a serious answer which redeemed the original comment. Most of the time I choose to downvote low effort comments like semi-relevant quotes from pop culture, because it triggers my post-traumatic ticks from past reddit experience.
It is a joke related to the episode 9 of the first season of Rick and Morty, where Jerry (the dad of Morty) does not want to change his belief concerning this fact he learned in highschool and make a big fuzz about it.

https://m.youtube.com/watch?v=S4E2ZuPCBG0

Pluto is an order of magnitude larger than Ceres, so its perfectly possible to define planet in such a way that pluto is a planet and ceres is not.
This is what I was thinking. Setting the minimum size to 2000Km diameter, and excluding satellites/mooons, we'd just have had to add one planet, if my reading is correct.
It's hard to justify counting Pluto without counting Eris:

- Eris is more massive than Pluto (1.6e22kg versus Pluto's 1.3e22kg)

- Eris is only slightly smaller than Pluto, at 2326km diameter (more than your arbitrary 2000km cutoff)

- The orbit of Eris crosses Pluto's, so it may be closer to the Sun part of the time https://solarstory.net/img/articles/big/orbit-of-eris.jpg

Agreed. Eris is the one I was referring to in my comment. Instead of removing Pluto, just add one planet(Eris).

On reread that probably wasn't clear, since I still think of Pluto as a planet.

Pluto got re-categorized as dwarf planet because there were now more like it. Therefore, if you still want to call it a planet, it definitely wouldn't be the 9th one.
This comment is probably going to go under most people heads.