angrysoba
Philosophile
We have Terrestrials and Jovians.
We have Terrestrials and Jovians.
But it isn't because it says for any future body to be considered a planet it has to meet criteria X.
theprestige
Penultimate Amazing
Since that was the explicit intent of Darat's proposal, what's the point of telling him? He already knows.
Start with the Nine Planets for historical reasons. Add new planets to the list using a different rule.
Belz...
Fiend God
Not tremendous enough.
Ok I'll settle for partial following of the definition.
I just it pointless. Either follow the rule you establish, or have a different rule that results in the same list.
mumblethrax
Species traitor
- Joined
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- Messages
- 5,021
The third criterion of the IAU definition gets a lot of attention, because it's the Pluto-killer, and I'm sympathetic to the criticism--at the very least, it's vague. We shouldn't have undefined metaphors like "clearing the neighborhood" in an operational definition.
But the first criterion--that a planet must be in orbit around the Sun--is just plain wrong. Even the provided motivation for coming up with a new definition of planet works against that one. I watched a clip of NdGT on Colbert a little while ago, where he argued that we don't want to think of all these trans-Neptunian objects as planets, and that's what forced the new definition--fair enough, I guess? But the topic then shifts to exoplanets which both Tyson and Colbert (without correction) repeatedly refer to as...planets.
Anyway, it doesn't seem important to me that calling these things planets would explode the number of planets. We used to know about one moon, and then a small handful, now we've identified nearly 200. Doesn't seem to have forced a new definition of moon (even though we could probably use one--Phobos and Deimos are ******** moons).
But the first criterion--that a planet must be in orbit around the Sun--is just plain wrong. Even the provided motivation for coming up with a new definition of planet works against that one. I watched a clip of NdGT on Colbert a little while ago, where he argued that we don't want to think of all these trans-Neptunian objects as planets, and that's what forced the new definition--fair enough, I guess? But the topic then shifts to exoplanets which both Tyson and Colbert (without correction) repeatedly refer to as...planets.
Anyway, it doesn't seem important to me that calling these things planets would explode the number of planets. We used to know about one moon, and then a small handful, now we've identified nearly 200. Doesn't seem to have forced a new definition of moon (even though we could probably use one--Phobos and Deimos are ******** moons).
angrysoba
Philosophile
Yeah, some moons are potato-shaped. Others are ridiculously tiny.
I am now persuaded that they should just make Pluto a planet again with all the other bloody dwarf planets whether they be five more or five hundred more.
Belz...
Fiend God
That's a very good point. I'd call any natural sattelite without hydrostatic equilibrium a 'moonlet'.
Belz...
Fiend God
What if the number is 10,000? Just asking.
We manage sets with orders of magnitude higher already in astronomy / cosmology so can't see why a big number is a problem.
theprestige
Penultimate Amazing
How do 10,000 dwarf planets solve the "too many things!" problem?
Belz...
Fiend God
Even though it's been explained numerous times?
The idea is that planets would be named. Planetoids need not be.
Ziggurat
Penultimate Amazing
- Joined
- Jun 19, 2003
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- 61,789
Ziggurat
Penultimate Amazing
- Joined
- Jun 19, 2003
- Messages
- 61,789
If we consider exoplanets to be planets, then we have to discard that idea anyways.
Belz...
Fiend God
The proper phrasing is "Asking for a friend."
Obviously, that's what I meant!!
Then I invite you to read the thread again. I don't mind repeating myself once or twice, but this is ridiculous.
Again, read the thread, man. I don't have time to teach you the basics all the way from kindergarten just so you can keep up.
theprestige
Penultimate Amazing
I did not object to your wording, Belz...
I objected to your premise:
I think you're making an argument from feelings. I think that calling it "the reasonable thing to do" doesn't change the fact that it's an argument from feelings.
I also happen to think that it's not necessary to "move beyond how things 'feel'", so if you want to abandon that premise that's fine with me. But as long as that is your premise, I expect your arguments to be consistent with it. Certainly if you hope to change my mind on the basis of that premise, your arguments will need to be consistent with that premise.
I do, obviously. Deviating from the general case brings up questions of special pleading, and risks inconsistency and even incoherency of thought.
I have. It sounds stupid. And the convenience sources I've found are rather lacking in detail. Where is the debate? What happened to the guy who pointed out that we didn't "demote" the gas giants to make taxonomy easier; we just subcategorized them? What happened to the guy who pointed out that Hertzsprung and Russell didn't start "demoting" stars to make an their job easier; they just did their job?
At the rate we're finding exoplanets, we're going to have 10,000 planets relatively soon anyway. Where will your ease-of-use god be then?
It's unavoidable, though.
I acknowledge it. I don't agree with it.
theprestige
Penultimate Amazing
Which is kind of the point, I think. The IAU's position seems to be, in summary, "if we call Pluto a planet, we have to call a lot of other things planets, and that's too much work. So we need a rule that's tailored specifically to admit most of the traditional planets, but exclude Pluto and things like Pluto."
Belz...
Fiend God
Well, by that logic you could call _every_ human decision based on feelings, because even when you're making a call based on data and evidence, say in peer-reviewing an article or when deliberating as a juror, you're going to make that call based on how 'good' it feels to you. But then that makes the distinction pointless. My initial point about feelings was not that it had to be a robot-like decision, but one at least based on some argument and evidence rather than just "eh, it doesn't feel right to me".
You mean it "feels" stupid, right?
Exactly where it is now, actually. I don't plan on naming all exoplanets, either.
theprestige
Penultimate Amazing
Here's a thought:
Man is the measure of all things.
Therefore, the definition of a planet should be first and foremost: "Earth."
A planet is any rocky body that:
- is gravi-spherical (or whatever)
- orbits in the Goldilocks zone of a star (but can potentially orbit another body in the zone)
- has a breathable atmosphere
- has a strong magnetic field (for some value of "strong")
- has seasons (probably due to axial tilt, but other mechanisms may be possible)
This definition has several advantages:
It dramatically reduces the number of "planets" that astronomers have to wrap their heads around.
It makes it clear that when an astronomer is studying a "planet", they're studying something substantially like Earth, and leveraging all the body of knowledge already accumulated about such objects.
It excites the public, since now when we say we've discovered a "planet" orbiting another star, we mean we've discovered a suitable destination for human interstellar travel. This is way better than saying we've discovered an exoplanet, but it turns out to be a quasi-brown-dwarf spinning through a searing radiation hell on the fringes of the stellar corona.
Man is the measure of all things.
Therefore, the definition of a planet should be first and foremost: "Earth."
A planet is any rocky body that:
- is gravi-spherical (or whatever)
- orbits in the Goldilocks zone of a star (but can potentially orbit another body in the zone)
- has a breathable atmosphere
- has a strong magnetic field (for some value of "strong")
- has seasons (probably due to axial tilt, but other mechanisms may be possible)
This definition has several advantages:
It dramatically reduces the number of "planets" that astronomers have to wrap their heads around.
It makes it clear that when an astronomer is studying a "planet", they're studying something substantially like Earth, and leveraging all the body of knowledge already accumulated about such objects.
It excites the public, since now when we say we've discovered a "planet" orbiting another star, we mean we've discovered a suitable destination for human interstellar travel. This is way better than saying we've discovered an exoplanet, but it turns out to be a quasi-brown-dwarf spinning through a searing radiation hell on the fringes of the stellar corona.
Belz...
Fiend God
You know, for a time I thought we were having a pleasant conversation about real ideas and criteria, until you came up with your insulting strawman.
Good luck with that.