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/

  • Cosmic Cleric@lemmy.world
    link
    fedilink
    English
    arrow-up
    1
    arrow-down
    3
    ·
    4 hours ago

    If you pick a random Earth-sized lump of the Sun as a potential planet, and swap its place with Earth, Earth would quickly get mixed in with the rest of the Sun and stop being a distinct entity, so be very silly to still call a planet,

    Why? Everything about Earth is still the same, skies, oceans, etc. Only difference is that it’s crowded in by other bodies now.

    Trying to scientifically judge if a body is a planet by something external to it, if it’s being crowded in our not, it’s not logical, and doesn’t change the body itself.

    What does a body clearing is orbit or not have anything to do with the body itself?

    Location makes some difference to whether or not something’s a planet.

    Only because a very few human beings astronomers illogically/arbitrarily decided that’s so. The reality on the ground for the body is that its still Earth, the planet we live on.

    Planetary Scientists should be deciding the rules, and not solely Astronomers.

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

    • AnyOldName3@lemmy.world
      link
      fedilink
      English
      arrow-up
      4
      arrow-down
      1
      ·
      4 hours 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.world
        link
        fedilink
        English
        arrow-up
        1
        ·
        edit-2
        3 hours 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

        • Magiilaro@feddit.org
          link
          fedilink
          English
          arrow-up
          1
          ·
          3 minutes ago

          One of the idea with “has the space around it cleared” is that the body has the right size and gravitational pull. The theoretical object in the Oort Cloud would relative fast clear the space around himself if it had the size to have a stable and long living internal heat source (that would either need lots of decaying nuclear material or would need to be at least about earth size to have enough stored energy to have a molten core).

          So if you put earth into the Oort Cloud it would still be a planet, because we know that earth has the potential to clean it’s neighborhood. Not that our definition would be relevant, because Earth in the Oort Cloud would be a lifeless rock very fast, with nobody left to care about definitions.

        • AnyOldName3@lemmy.world
          link
          fedilink
          English
          arrow-up
          1
          arrow-down
          1
          ·
          3 hours 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.world
            link
            fedilink
            English
            arrow-up
            1
            ·
            edit-2
            3 hours 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