Pluto is was and always will be a planet

arthwollipot said:
My problem with considering Pluto a planet is this. We can divide the solar system's large bodies up into three discrete categories: Rocky planets (Mercury, Venus, Earth, Mars), gas giants (Jupiter, Saturn, Uranus, Neptune), and Pluto. Pluto isn't a gas giant, and it isn't a rocky planet like the others - it orbits too far away, eccentrically, sometimes coming inside the orbit of Neptune. It falls into a category all of its own.

Except that it doesn't. It is similar to other trans-Neptunian Kuiper Belt objects like Makimaki and Haumea. Let's put it in the same category as them.
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Yay!
Agreed
 
angrysoba said:
Sure! Why not? The Terrestrial Planets, the Asteroids, the Jovian Planets, the Kuiper Belt Planets (Pluto, Charon, Eris, Makemake, Haumea, Sedna, etc...).
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Toids' ain't planets. Neither are the Kuiper Elves and Makemake can take a hikehike.
 
Belz... said:
Oh, then maybe we should all use the IAU definition?
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The IAU definition is the one we're stuck with, obviously. For now, at least. But this thread is in part about dissent from the IAU. It is in that spirit that I offer my comments.

If you disagree with the dissent, and prefer the IAU definition, use that. If you also dissent, but prefer a different definition and terminology than the other dissenters, use that.

But if all you're trying to do is needle people for dissenting from the IAU... Then stop being a dick.

In conclusion:

"IAU delenda est."

- Cato the Elder, probably
 
theprestige said:
The IAU definition is the one we're stuck with, obviously. For now, at least. But this thread is in part about dissent from the IAU. It is in that spirit that I offer my comments.
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Well is it being a dick to stick with one's personal definition or not?

But if all you're trying to do is needle people for dissenting from the IAU... Then stop being a dick.
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What in the blue **** are you babbling about?
 
Belz... said:
Same thing as calling anything else whatever it's called: it's a way to know what thing we're refering to.
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I think I get your meaning but you could refer objects in the solar system theirs names even if we had no categories for them at all.

We use categories to more easily understand what they thing is so we can infer things about it without having to explicitly state them in every discussion. Yes these categories are arbitrary, yes a slightly different set of categories could also work, but at the end of the day the people who work most closely with these categories voted on the categories they thought would be most useful and/or descriptive. Since any categories would be arbitrary, this seems like it’s probably be the best way to go about defining them.
 
theprestige said:
The IAU definition is the one we're stuck with, obviously. For now, at least. But this thread is in part about dissent from the IAU. It is in that spirit that I offer my comments.

If you disagree with the dissent, and prefer the IAU definition, use that. If you also dissent, but prefer a different definition and terminology than the other dissenters, use that.
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No. While the exact definition we use may not matter greatly, consistency is still very important. When we call something a planet it allows us to infer things about the object we are discussing. Having different definitions would create nothing but confusion.
theprestige said:
But if all you're trying to do is needle people for dissenting from the IAU... Then stop being a dick.
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Dissent with why it's defined that way all you want so long as when you enter into discussions and call something a planet you are using the same formal definition everyone else is,.
 
Belz... said:
Depends what you mean. The Moon being farther, it'll be less affected by the earth's gravity. Doesn't that affect the Earth's dominance?
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How are you defining dominance? Absolute acceleration? Relative acceleration? Note that I'm using acceleration and not force because the force on the Moon from the Earth is necessarily identical to the force on the Earth from the Moon.

The absolute acceleration the Earth exerts on the Moon certainly decreases the farther away it gets. But that would be true if the moon were less massive as well such that an orbit at that same distance didn't produce a barycenter above the earth's surface. And the relative acceleration of the moon due to the earth compared to the earth due to the moon is going to be constant regardless of barycenter location.

Furthermore, whether the barycenter lies inside or outside the surface can also depend upon the density of the more massive body, but the external gravitational effect of the more massive body is really just a function of total mass. If the Earth had the same density as Pluto but with its current mass, I don't think the Moon-Earth barycenter would ever get beyond the surface.

And how do you handle elliptical orbits? The barycenter can oscillate back and forth through the surface of the more massive body. Is it a moon for part of the orbit but a planet for part?

Using barycenter location is not a good criteria for moon versus planet distinctions.
 
lomiller said:
No. While the exact definition we use may not matter greatly, consistency is still very important. When we call something a planet it allows us to infer things about the object we are discussing. Having different definitions would create nothing but confusion.
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People who find this thread confusing will probably be happiest reading other threads instead. Certainly Belz... didn't seem to be confused about my meaning, when he replied to my post with his "planetoid" comment.

Dissent with why it's defined that way all you want so long as when you enter into discussions and call something a planet you are using the same formal definition everyone else is,.
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Put me in a formal conversation, and I'll happily use the formal definition. To avoid unnecessary confusion, for one thing. But also to avoid derailing a productive discussion with a slapfight about definitions.

Hell, I'd even use the formal definitions in an informal discussion, if I was concerned about unnecessary confusion in that discussion. But when my mom talks about "the planet Pluto", I don't worry that she's incorrectly inferring that it's cleared its neighborhood.

And really, a thread about dissenting from the IAU definition should be one place where one is reasonably free to use alternate definitions without being taken to task over some doctrinaire idea of obligation to the IAU.

And in conclusion: IAU delenda est
 
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theprestige said:
People who find this thread confusing will probably be happiest reading other threads instead. Certainly Belz... didn't seem to be confused about my meaning, when he replied to my post with his "planetoid" comment.


Put me in a formal conversation, and I'll happily use the formal definition. To avoid unnecessary confusion, for one thing. But also to avoid derailing a productive discussion with a slapfight about definitions.

Hell, I'd even use the formal definitions in an informal discussion, if I was concerned about unnecessary confusion in that discussion. But when my mom talks about "the planet Pluto", I don't worry that she's incorrectly inferring that it's cleared its neighborhood.

And really, a thread about dissenting from the IAU definition should be one place where one is reasonably free to use alternate definitions without being taken to task over some doctrinaire idea of obligation to the IAU.

And in conclusion: IAU delenda est
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While the thread may be about the IAU definition (actually it’s supposed to be about the somewhat questionable paper in the OP) that wasn’t what I responded to. Your statement about using whichever definition you prefer was both clear and wrong. Disagreeing with the recognised definition is not a licence to use a different one.
 
lomiller said:
While the thread may be about the IAU definition (actually it’s supposed to be about the somewhat questionable paper in the OP) that wasn’t what I responded to. Your statement about using whichever definition you prefer was both clear and wrong. Disagreeing with the recognised definition is not a licence to use a different one.
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Indeed. Otherwise the woo-woo tactic of discrediting, say, science in order to bolster creationism would be valid.
 
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