https://xkcd.com/2908

Alt text:

Astronomers are a little unsure of the applicability of this index, but NASA’s Planetary Protection Officer is all in favor.

    • teft@lemmy.world
      link
      fedilink
      English
      arrow-up
      6
      ·
      8 months ago

      Pluto-charon shouldn’t count since it is more akin to a binary planetary system than a planet-moon system. Charon and Pluto are so close in size that the system has a barycenter outside of Pluto. This means instead of Charon orbiting a point inside Pluto, Charon and Pluto orbit a point about 800 km above Pluto’s surface.