There is no objective criteria for what a planet is and isn’t
There are - exactly three.
is in orbit around a star,
has sufficient mass to assume hydrostatic equilibrium (a nearly round shape), and
has “cleared the neighbourhood” around its orbit.
The last one means that its gravitational pull has removed any smaller objects that might be in its orbit, either by kicking them out of it, or by catching them as moons.
Because that sentence doesn’t really make sense. “Criteria” is a human concept. Nature doesn’t do “criteria”, nor “objective” for that matter. So, yes, there’s no “natural criteria” for when something is X or Y, we, humans, make those criteria. Doesn’t matter if it’s in relation to animals, plants, or planets.
Not objective in the sense that aliens would come to the same definition for what is and isn’t a planet. Compare that to something like what the elements are.
The scientific community was basically backed into a corner: either create a new category for Pluto and similar bodies, or we go from 9 planets to over 3,000 (iirc), lol.
There are - exactly three.
The last one means that its gravitational pull has removed any smaller objects that might be in its orbit, either by kicking them out of it, or by catching them as moons.
Pluto’s orbit is full of debris.
You’re the second person to ignore the sentence immediately following that.
Because that sentence doesn’t really make sense. “Criteria” is a human concept. Nature doesn’t do “criteria”, nor “objective” for that matter. So, yes, there’s no “natural criteria” for when something is X or Y, we, humans, make those criteria. Doesn’t matter if it’s in relation to animals, plants, or planets.
So you’re saying things just exist, and as humans we categorize them? Because that’s what I said.
The idea of a “category” is inherently human. Just like “objective” and “criteria”.
Which means there is objective criteria for what is categorised as a planet - it’s whatever we, humans, define them to be.
Not objective in the sense that aliens would come to the same definition for what is and isn’t a planet. Compare that to something like what the elements are.
The scientific community was basically backed into a corner: either create a new category for Pluto and similar bodies, or we go from 9 planets to over 3,000 (iirc), lol.
The only sensible choice was made, imo.