Poor Pluto. One day you’re a planet, the next day you’re a “dwarf with potential.”

  • @[email protected]
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    329 days ago

    The explanation I heard back then was that Pluto wouldn’t qualify as a planet, EXCEPT that it has a moon. I’m not sure why that exception would apply, but it seems it’s no longer good enough.

    • zqps
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      529 days ago

      That was an attempt to preserve the order of planets, but a failed one since there are other non-planets with moons. https://xkcd.com/3063

      The modern definition doesn’t depend on moons. Which is good because not all planets have them.

    • dual_sport_dork 🐧🗡️
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      429 days ago

      Well, there are seven other known sub-planetary bodies (dwarf planets) in the solar system that also have moons: Eris, Haumea, Makemake, Gonggong, Quaoar, Orcus, and Salacia. Eris in particular is larger than Pluto. So then Eris would have to be promoted to being a planet, too. Along with the other six, plus any more we might discover later. At the time of its discovery I don’t think anyone had yet observed that Pluto has a moon, and it wasn’t discovered until even later that Pluto actually has five moons.