
Thirteen planets and counting - okket
https://blogs.egu.eu/divisions/gd/2018/07/25/thirteen-planets-and-counting/
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Sharlin
I like the term "world" to denote a roughly spherical body with evidence of
interesting dynamics happening, or at least having happened. It's poetic and
evocative—but not excessively so. Emily Lakdawalla of Planetary Society fame
uses it in that sense.

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zuminator
Although this is explicitly at odds with the author's intentions, I don't
think there should be an overlap of any kind between "moon" and "planet." So
I'd modify his definition of "A planet is a sub-stellar mass body that has
never undergone nuclear fusion and that has sufficient self-gravitation to
assume a spheroidal shape adequately described by a triaxial ellipsoid
regardless of its orbital parameters" to add: "excluding any object that
orbits a point located within a planet." Thus our Moon would remain a moon but
Pluto-Charon could be a double planet because the point they revolve around is
not within either body.

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bena
It's a weird issue because really it's all vaguely arbitrary distinctions.

There's nothing really different between the various celestial bodies and at
the same time they're all so vastly different from each other. You have
planetary satellites larger than some planets. A couple of planets that are
pretty much failed stars.

Even things like comets and asteroids, they're really just defined by
behavior. I mean the definition of asteroid is basically "not a planet or
comet".

It's basically all "stuff in space".

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Retric
> arbitrary distinctions.

Exactly, the current definition of planet is not that useful. If a moon
happens to exist in the goldilocks zone it could easily support life even if
it's sitting next to a Jupiter sized planet that does not.

