Planet Definitions
xkcd.com

Under the ‘has cleared its orbital neighborhood’ and ‘fuses hydrogen into helium’ definitions, thanks to human activities Earth technically no longer qualifies as a planet but DOES count as a star.

https://explainxkcd.com/3063/

  • AnyOldName3@lemmy.worldEnglish
    41·
    7 days ago

    I personally don’t think they can be counted as skies and oceans etc. anymore when they’re being mixed in with multi-thousand-degree hydrogen/helium plasma. On a cosmological timescale, the Earth is converted to just more plasma in an instant. The reality on the ground of the body is that the ground’s gone and everything living there is gone and so’s the mantle under the ground. Things are defined partially by their interactions with their surroundings and the state they’re currently in, not how they used to be. Theia is not a planet, even if the theory where it once was turns out to be right. It stopped being a planet when it collided with the Earth, disintegrated, and re-accreted into parts of the Earth and the Moon.

    • Cosmic Cleric@lemmy.worldEnglish
      1·
      7 days ago

      I personally don’t think they can be counted as skies and oceans etc. anymore when they’re being mixed in with multi-thousand-degree hydrogen/helium plasma.

      So Mars never had oceans? Or an atmosphere?

      So Saturn’s moon Titan doesn’t have lakes? Or an atmosphere?

      What happens if a body is found in the Oort Cloud that has an internal heat source so that it has a internal ocean like Europa? It’s it still not a planet because the space around it is busy?

      This comment is licensed under CC BY-NC-SA 4.0

      • AnyOldName3@lemmy.worldEnglish
        11·
        7 days ago

        Your original idea only holds if it’s still valid to claim Mars still has oceans, even though they’re all gone. When things stop existing, it changes their properties.

        • Cosmic Cleric@lemmy.worldEnglish
          1·
          7 days ago

          Your original idea only holds if it’s still valid to claim Mars still has oceans, even though they’re all gone. When things stop existing, it changes their properties.

          My latest point was to counter your latest point that things like bodies of water or atmosphere should not be considered criteria for identifying a planet or not,

          Also, Mars may still have water, under the surface.

          This comment is licensed under CC BY-NC-SA 4.0

          • AnyOldName3@lemmy.worldEnglish
            11·
            7 days ago

            That wasn’t a point I made. You said the Earth’s skies and oceans would be the same after the hypothetical Earth swaps places with an Earth-sized lump of the Sun event, and I pointed out that they’d be destroyed within seconds. That was kind of separate to the original poorly-thought-through suggestion you made about planet location swaps, and was a second poorly-thought-through claim.