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Comment by Aerolfos | original | For first time, a cell built from scratch grows and divides
[−]Aerolfos · 2026-07-01 Wed 17:48 UTC · link
Actually, that is the IAU stance. And their definition for exoplanet includes small, non-rounded objects orbiting stars which would be asteroids (or comets or whatever) if they happened to be around the Sun.

All that debacle around dwarf planets to prepare for future observations, and yet the distinction ceases to apply the moment you go outside the Oort cloud...

But really, that's just the naming systems being bad, obviously common people don't think asteroids around other stars are "exoplanets" or should be called that way

[−]hparadiz · 2026-07-01 Wed 17:52 UTC · link
I'm not talking about edge cases like asteroids or planetoids or dwarf planets. I'm talking about actual planets. Like a gas giant orbiting a star. It's obviously a planet even if it's not orbiting Sol.
[−]ben_w · 2026-07-01 Wed 18:53 UTC · link
It's perfectly coherent to argue that gas giants should count failed stars rather than as planets, given the boundary between them is under debate.

https://en.wikipedia.org/wiki/WISE_0855%E2%88%920714

[−]jibal · 2026-07-01 Wed 20:33 UTC · link
It's perfectly irrelevant to the thread.
[−]ben_w · 2026-07-02 Thu 05:24 UTC · link
This thread is ~

  "Exoplanets also aren't planets": discuss
As the easiest to discover exoplanets (and all the early ones except pulsar planets) are gas giants, and the comment I was directly replying to had "Like a gas giant orbiting a star. It's obviously a planet", therefore "gas giants are failed stars and shouldn't count as planets" is not at all irrelevant.

Even further up to the point of if these are or are not cell, it illustrates how taxonomical categories are made by humans for humans. Historically, any connection to natural laws in taxonomies is often mere coincidence.

[−]jibal · 2026-07-01 Wed 23:45 UTC · link
This is quite wrong.

https://www.iau.org/IAU/Science/What-we-do/Pluto-and-the-Dev...

"More generally, a planet:

a. orbits its host star, just as the Earth and Jupiter orbit the Sun,

b. is large enough to be mostly round, and

c. must have an important influence on the orbital stability of the other objects in its neighbourhood."

Exoplanets are planets by that definition where the host star is not our Sun:

"Researchers have found hundreds of extrasolar planets, or exoplanets, that reside outside our solar system. "