Help name the moons of Pluto

[Rhubarbodendron]

how about Endor?

[The Mirrorball Man]

Rhubarbodendron wrote:

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how about Endor?

Does Pluto have forest moons?

[Rhubarbodendron]

well, where there are dogs [->Pluto], there must be something with a bark. And something to pee on..

[RJDiogenes]

Christopher wrote:

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I think the best solution is to keep the dwarf planet category, because it's useful, but to eliminate the paradoxical notion that a dwarf planet is not a planet. A dwarf star is still a star, a dwarf galaxy is still a galaxy, and so on, so that just doesn't make sense. And we have other subdivisions of "planet" as a category, such as giant planets and terrestrial planets. We just need to treat "planet" as a class that has numerous subdivisions.

That's what makes the most sense to me. If the definition can include objects as diverse as Jupiter and Mercury, there's no reason why it can't include Plutonian objects.

[Rhubarbodendron]

I am inclined to agree, but then think of the asteroid belt in our solar system. There are man rather big objects in there and there are a few tiny dwarf planets. Where would one draw the line between dwarf planet and gigant asteroid? And there appear to be many more larger objects to be lurking beyond Pluto. Having more than 25 planets could indeed make our solar system a bit difficult for laypersons like school kids.

How about counting anything as a planet that revolts directly around a sun plus has an atmosphere or used to have one?
With this definition we could keep all the original planets*, exclude big asteroids and include the more interesting objects yet to be found.

Only Jupiter's moon Europa would cause difficulties as it does indeed have traces of an atmosphere. It's a matter of definition if we consider Europa/Jupiter to be a binary planet (after all there are binary suns) or if we exclude Europa, based on the fact that it's not immediately circling the sun.



*The upper layers of a gas gigant would count as atmosphere, imo,so that Jupiter would count. Mercury has no atmosphere atm but it used to have one, originally.

[CorporalCaptain]

Rhubarbodendron wrote:

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Having more than 25 planets could indeed make our solar system a bit difficult for laypersons like school kids.

Yeah, they have enough difficulty with the countries of the world, the Presidents, the states and their capitals, the multiplication table, and those other things that I can't even remember right now.

[Alidar Jarok]

RJDiogenes wrote:

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That's what makes the most sense to me. If the definition can include objects as diverse as Jupiter and Mercury, there's no reason why it can't include Plutonian objects.

Shouldn't they be Erisian objects? I'm confused at why you aren't arguing more for Eris than Pluto, since it's a more massive dwarf planet.

[Rhubarbodendron]

good point. I think it's because we grew up with the (then) fact that the solar system consists of 9 Planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptun and Pluto (and their respective satellites plus an asteroid belt).
It's a bit like someone would abolish the number 5 - we'd still automatically count 1,2,3,4,5 instead of 1,2,3,4,6.

[Christopher]

Rhubarbodendron wrote:

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I am inclined to agree, but then think of the asteroid belt in our solar system. There are man rather big objects in there and there are a few tiny dwarf planets. Where would one draw the line between dwarf planet and gigant asteroid?

Actually that's incorrect. There's only one body in the Main Asteroid Belt that definitely qualifies as a dwarf planet, namely Ceres. The line you're asking about has already been drawn: a body is considered a dwarf planet if it's in a gravitationally relaxed state due to hydrostatic equilibrium, i.e. if it's massive enough to pull itself into a spheroidal shape. Ceres is the only Main Belt object that definitely meets that qualification. Vesta, the asteroid visited by the Dawn spacecraft last year, may also qualify as a dwarf planet, though it's hard to be sure because its shape has been distorted by an enormous impact event in its past, so the jury's still out.

And there appear to be many more larger objects to be lurking beyond Pluto. Having more than 25 planets could indeed make our solar system a bit difficult for laypersons like school kids.

On the other hand, there are over a hundred countries on Earth and thousands of cities, rivers, mountains, etc. Should we narrow the definition of a country or city in order to make geography class less challenging?

I think the best approach for the future would be to teach about the Solar System by region: the inner system containing the four terrestrial planets and Near-Earth asteroids; the Main Asteroid Belt containing Ceres, Vesta, and countless smaller objects; the middle system containing the two gas giants, two ice giants, and their extensive moon and ring systems as well as Trojan asteroids; the Kuiper Belt containing Pluto and countless icy minor objects; the outer system containing an as-yet-undetermined number of dwarf planets, minor objects, and possibly larger planets, as well as the heliopause; and the Oort Cloud forming a vast halo around the system.

How about counting anything as a planet that revolts directly around a sun plus has an atmosphere or used to have one?
With this definition we could keep all the original planets*, exclude big asteroids and include the more interesting objects yet to be found.

We shouldn't try to find an arbitrary definition that lets us keep our old preconceptions. Science doesn't work that way. We should amend our definitions and conceptions to fit new evidence and insights.

Alidar Jarok wrote:

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Shouldn't they be Erisian objects? I'm confused at why you aren't arguing more for Eris than Pluto, since it's a more massive dwarf planet.

But there could be more massive ones still that we haven't yet discovered. It does make a certain amount of sense to name a category after the first example discovered -- for instance, T Tauri stars, or all the dinosaur species named after the location where the first fossil was unearthed. And trans-Neptunian dwarf planets are already called plutoids (although I think that's kind of a silly category because it includes all dwarf planets except Ceres and maybe Vesta).

[Rhubarbodendron]

Christopher wrote:

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On the other hand, there are over a hundred countries on Earth and thousands of cities, rivers, mountains, etc. Should we narrow the definition of a country or city in order to make geography class less challenging?

You don't mean you've had to learn every single country and their major cities and rivers at school?! Jeeeeeeeeeeeeez! My commiserations! We just had to learn those on our continent, the US (location, capital & great lakes) and the USSR (Location, capital, resources & major climatical zones).

[Christopher]

^No, that's just my point -- I didn't have to learn it all. It's easy to teach the names of 8 or 9 planets, but if there were dozens or hundreds, I doubt students would be expected to know them all any more than they're expected to know the name of every country. That's why I suggested teaching about the Solar System region by region rather than planet by planet. Give an overview of what kinds of objects are found in each region, teach the biggest and most prominent ones in each region, but don't require an exhaustive list. Basically treat the regions of the system analogously to how you'd treat the continents when teaching geography.

[Zion Ravescene]

I chose Cerberus and Erebus, although as a write-in I considered George and Gracie, or McVie and Buckingham, so what do I know?

[RJDiogenes]

Rhubarbodendron wrote:

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How about counting anything as a planet that revolts directly around a sun plus has an atmosphere or used to have one?
With this definition we could keep all the original planets*, exclude big asteroids and include the more interesting objects yet to be found.

But that's my point-- the definition shouldn't be designed to exclude or include specific objects. The definition should be made based on certain criteria, just as in the categorization of stars or species, and then stuff will either fit the definition or not. In my opinion, a planet should be an object that is large enough to reach hydrostatic equilibrium and orbits a star.

Only Jupiter's moon Europa would cause difficulties as it does indeed have traces of an atmosphere. It's a matter of definition if we consider Europa/Jupiter to be a binary planet (after all there are binary suns) or if we exclude Europa, based on the fact that it's not immediately circling the sun.

Titan has a dense atmosphere, and other moons have atmospheres to various degrees. But that doesn't matter. If it orbits a planet, it's a moon. If something the size of Neptune was orbiting Jupiter, it would still be a moon.

Alidar Jarok wrote:

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Shouldn't they be Erisian objects? I'm confused at why you aren't arguing more for Eris than Pluto, since it's a more massive dwarf planet.

There are several terms bandied about. It doesn't really matter which one you prefer. The point is that the definition of planet is arbitrary and inconsistent, and was made for political rather than scientific reasons.

[Alidar Jarok]

It was made to keep the number small, but it was still a scientific decision because classifying things with definitions is the scientific thing to do. The political thing would be to call Pluto a planet and Eris a Dwarf Planet because people are used to Pluto as a planet.

[Tiberius]

Christopher wrote:

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It's easy to teach the names of 8 or 9 planets, but if there were dozens or hundreds, I doubt students would be expected to know them all any more than they're expected to know the name of every country.

Oh rubbish. We remember the names of countless millions of recurring characters in DS9, didn't we?

Oh, and about the countries...

https://www.youtube.com/watch?v=IDtdQ8bTvRc